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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 "DFGMaximalFlushInsertionPhase.h"
#if ENABLE(DFG_JIT)
#include "DFGBasicBlockInlines.h"
#include "DFGGraph.h"
#include "DFGInsertionSet.h"
#include "DFGPhase.h"
#include "JSCInlines.h"
namespace JSC { namespace DFG {
class MaximalFlushInsertionPhase : public Phase {
public:
MaximalFlushInsertionPhase(Graph& graph)
: Phase(graph, "maximal flush insertion phase")
{
}
bool run()
{
DFG_ASSERT(m_graph, nullptr, m_graph.m_form == LoadStore);
InsertionSet insertionSet(m_graph);
for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {
treatRegularBlock(block, insertionSet);
insertionSet.execute(block);
}
treatRootBlock(m_graph.block(0), insertionSet);
insertionSet.execute(m_graph.block(0));
return true;
}
void treatRegularBlock(BasicBlock* block, InsertionSet& insertionSet)
{
Operands<VariableAccessData*> currentBlockAccessData(block->variablesAtTail.numberOfArguments(), block->variablesAtTail.numberOfLocals(), nullptr);
// Insert a Flush before every SetLocal to properly pattern the graph such that
// any range between SetLocal and Flush has access to the local on the stack.
{
for (unsigned i = 0; i < block->size(); i++) {
Node* node = block->at(i);
bool isPrimordialSetArgument = node->op() == SetArgument && node->local().isArgument() && node == m_graph.m_arguments[node->local().toArgument()];
if (node->op() == SetLocal || (node->op() == SetArgument && !isPrimordialSetArgument)) {
VirtualRegister operand = node->local();
VariableAccessData* flushAccessData = currentBlockAccessData.operand(operand);
if (!flushAccessData)
flushAccessData = newVariableAccessData(operand);
insertionSet.insertNode(i, SpecNone,
Flush, node->origin, OpInfo(flushAccessData));
}
if (node->accessesStack(m_graph))
currentBlockAccessData.operand(node->local()) = node->variableAccessData();
}
}
// Flush everything at the end of the block.
{
NodeOrigin origin = block->at(block->size() - 1)->origin;
auto insertFlushAtEnd = [&] (VirtualRegister operand) {
VariableAccessData* accessData = currentBlockAccessData.operand(operand);
if (!accessData)
accessData = newVariableAccessData(operand);
currentBlockAccessData.operand(operand) = accessData;
insertionSet.insertNode(block->size(), SpecNone,
Flush, origin, OpInfo(accessData));
};
for (unsigned i = 0; i < block->variablesAtTail.numberOfLocals(); i++)
insertFlushAtEnd(virtualRegisterForLocal(i));
for (unsigned i = 0; i < block->variablesAtTail.numberOfArguments(); i++)
insertFlushAtEnd(virtualRegisterForArgument(i));
}
}
void treatRootBlock(BasicBlock* block, InsertionSet& insertionSet)
{
Operands<VariableAccessData*> initialAccessData(block->variablesAtTail.numberOfArguments(), block->variablesAtTail.numberOfLocals(), nullptr);
Operands<Node*> initialAccessNodes(block->variablesAtTail.numberOfArguments(), block->variablesAtTail.numberOfLocals(), nullptr);
for (auto* node : *block) {
if (!node->accessesStack(m_graph))
continue;
VirtualRegister operand = node->local();
if (initialAccessData.operand(operand))
continue;
DFG_ASSERT(m_graph, node, node->op() != SetLocal); // We should have inserted a Flush before this!
initialAccessData.operand(operand) = node->variableAccessData();
initialAccessNodes.operand(operand) = node;
}
// We want every Flush to be able to reach backwards to
// a SetLocal. Doing this in the root block achieves this goal.
NodeOrigin origin = block->at(0)->origin;
Node* undefined = insertionSet.insertConstant(0, origin, jsUndefined());
for (unsigned i = 0; i < block->variablesAtTail.numberOfLocals(); i++) {
VirtualRegister operand = virtualRegisterForLocal(i);
VariableAccessData* accessData;
DFG_ASSERT(m_graph, nullptr, initialAccessNodes.operand(operand)->op() == Flush); // We should have inserted a Flush before any SetLocal/SetArgument for the local that we are analyzing now.
accessData = initialAccessData.operand(operand);
DFG_ASSERT(m_graph, nullptr, accessData);
insertionSet.insertNode(0, SpecNone,
SetLocal, origin, OpInfo(accessData), Edge(undefined));
}
}
VariableAccessData* newVariableAccessData(VirtualRegister operand)
{
ASSERT(!operand.isConstant());
m_graph.m_variableAccessData.append(VariableAccessData(operand));
return &m_graph.m_variableAccessData.last();
}
};
bool performMaximalFlushInsertion(Graph& graph)
{
return runPhase<MaximalFlushInsertionPhase>(graph);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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