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/*
* Copyright (C) 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 "DFGConstantHoistingPhase.h"
#if ENABLE(DFG_JIT)
#include "DFGGraph.h"
#include "DFGInsertionSet.h"
#include "DFGPhase.h"
#include "JSCJSValueInlines.h"
namespace JSC { namespace DFG {
namespace {
class ConstantHoistingPhase : public Phase {
public:
ConstantHoistingPhase(Graph& graph)
: Phase(graph, "constant hoisting")
{
}
bool run()
{
DFG_ASSERT(m_graph, nullptr, m_graph.m_form == SSA);
m_graph.clearReplacements();
HashMap<FrozenValue*, Node*> jsValues;
HashMap<FrozenValue*, Node*> doubleValues;
HashMap<FrozenValue*, Node*> int52Values;
auto valuesFor = [&] (NodeType op) -> HashMap<FrozenValue*, Node*>& {
// Use a roundabout approach because clang thinks that this closure returning a
// reference to a stack-allocated value in outer scope is a bug. It's not.
HashMap<FrozenValue*, Node*>* result;
switch (op) {
case JSConstant:
result = &jsValues;
break;
case DoubleConstant:
result = &doubleValues;
break;
case Int52Constant:
result = &int52Values;
break;
default:
DFG_CRASH(m_graph, nullptr, "Invalid node type in valuesFor()");
result = nullptr;
break;
}
return *result;
};
Vector<Node*> toFree;
for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {
unsigned sourceIndex = 0;
unsigned targetIndex = 0;
while (sourceIndex < block->size()) {
Node* node = block->at(sourceIndex++);
switch (node->op()) {
case JSConstant:
case DoubleConstant:
case Int52Constant: {
HashMap<FrozenValue*, Node*>& values = valuesFor(node->op());
auto result = values.add(node->constant(), node);
if (result.isNewEntry)
node->origin = m_graph.block(0)->at(0)->origin;
else {
node->setReplacement(result.iterator->value);
toFree.append(node);
}
break;
}
default:
block->at(targetIndex++) = node;
break;
}
}
block->resize(targetIndex);
}
// Insert the constants into the root block.
InsertionSet insertionSet(m_graph);
auto insertConstants = [&] (const HashMap<FrozenValue*, Node*>& values) {
for (auto& entry : values)
insertionSet.insert(0, entry.value);
};
insertConstants(jsValues);
insertConstants(doubleValues);
insertConstants(int52Values);
insertionSet.execute(m_graph.block(0));
// Perform all of the substitutions. We want all instances of the removed constants to
// point at their replacements.
for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {
for (Node* node : *block)
m_graph.performSubstitution(node);
}
// And finally free the constants that we removed.
m_graph.invalidateNodeLiveness();
for (Node* node : toFree)
m_graph.deleteNode(node);
return true;
}
};
} // anonymous namespace
bool performConstantHoisting(Graph& graph)
{
return runPhase<ConstantHoistingPhase>(graph);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)