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/*
* Copyright (C) 2013, 2014 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 "DFGOSREntrypointCreationPhase.h"
#if ENABLE(DFG_JIT)
#include "DFGBasicBlockInlines.h"
#include "DFGBlockInsertionSet.h"
#include "DFGGraph.h"
#include "DFGLoopPreHeaderCreationPhase.h"
#include "DFGPhase.h"
#include "JSCInlines.h"
namespace JSC { namespace DFG {
class OSREntrypointCreationPhase : public Phase {
public:
OSREntrypointCreationPhase(Graph& graph)
: Phase(graph, "OSR entrypoint creation")
{
}
bool run()
{
RELEASE_ASSERT(m_graph.m_plan.mode == FTLForOSREntryMode);
RELEASE_ASSERT(m_graph.m_form == ThreadedCPS);
unsigned bytecodeIndex = m_graph.m_plan.osrEntryBytecodeIndex;
RELEASE_ASSERT(bytecodeIndex);
RELEASE_ASSERT(bytecodeIndex != UINT_MAX);
// Needed by createPreHeader().
m_graph.m_dominators.computeIfNecessary(m_graph);
CodeBlock* baseline = m_graph.m_profiledBlock;
BasicBlock* target = 0;
for (unsigned blockIndex = m_graph.numBlocks(); blockIndex--;) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
unsigned nodeIndex = 0;
Node* firstNode = block->at(0);
while (firstNode->isSemanticallySkippable())
firstNode = block->at(++nodeIndex);
if (firstNode->op() == LoopHint
&& firstNode->origin.semantic == CodeOrigin(bytecodeIndex)) {
target = block;
break;
}
}
if (!target) {
// This is a terrible outcome. It shouldn't often happen but it might
// happen and so we should defend against it. If it happens, then this
// compilation is a failure.
return false;
}
BlockInsertionSet insertionSet(m_graph);
// We say that the execution count of the entry block is 1, because we know for sure
// that this must be the case. Under our definition of executionCount, "1" means "once
// per invocation". We could have said NaN here, since that would ask any clients of
// executionCount to use best judgement - but that seems unnecessary since we know for
// sure what the executionCount should be in this case.
BasicBlock* newRoot = insertionSet.insert(0, 1);
NodeOrigin origin = target->at(0)->origin;
Vector<Node*> locals(baseline->m_numCalleeRegisters);
for (int local = 0; local < baseline->m_numCalleeRegisters; ++local) {
Node* previousHead = target->variablesAtHead.local(local);
if (!previousHead)
continue;
VariableAccessData* variable = previousHead->variableAccessData();
locals[local] = newRoot->appendNode(
m_graph, variable->prediction(), ExtractOSREntryLocal, origin,
OpInfo(variable->local().offset()));
newRoot->appendNode(
m_graph, SpecNone, MovHint, origin, OpInfo(variable->local().offset()),
Edge(locals[local]));
}
for (int argument = 0; argument < baseline->numParameters(); ++argument) {
Node* oldNode = target->variablesAtHead.argument(argument);
if (!oldNode) {
// Just for sanity, always have a SetArgument even if it's not needed.
oldNode = m_graph.m_arguments[argument];
}
Node* node = newRoot->appendNode(
m_graph, SpecNone, SetArgument, origin,
OpInfo(oldNode->variableAccessData()));
m_graph.m_arguments[argument] = node;
}
for (int local = 0; local < baseline->m_numCalleeRegisters; ++local) {
Node* previousHead = target->variablesAtHead.local(local);
if (!previousHead)
continue;
VariableAccessData* variable = previousHead->variableAccessData();
Node* node = locals[local];
newRoot->appendNode(
m_graph, SpecNone, SetLocal, origin, OpInfo(variable), Edge(node));
}
newRoot->appendNode(
m_graph, SpecNone, Jump, origin,
OpInfo(createPreHeader(m_graph, insertionSet, target)));
insertionSet.execute();
m_graph.resetReachability();
m_graph.killUnreachableBlocks();
return true;
}
};
bool performOSREntrypointCreation(Graph& graph)
{
SamplingRegion samplingRegion("DFG OSR Entrypoint Creation");
return runPhase<OSREntrypointCreationPhase>(graph);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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