DFGConstantHoistingPhase.cpp [plain text]
#include "config.h"
#include "DFGConstantHoistingPhase.h"
#if ENABLE(DFG_JIT)
#include "DFGGraph.h"
#include "DFGInsertionSet.h"
#include "DFGPhase.h"
#include "DFGPredictionPropagationPhase.h"
#include "DFGVariableAccessDataDump.h"
#include "JSCInlines.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*>& {
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 = NodeOrigin();
else {
node->setReplacement(result.iterator->value);
toFree.append(node);
}
break;
}
default:
block->at(targetIndex++) = node;
break;
}
}
block->resize(targetIndex);
}
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));
for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {
for (Node* node : *block)
m_graph.performSubstitution(node);
}
for (Node* node : toFree)
m_graph.m_allocator.free(node);
return true;
}
};
}
bool performConstantHoisting(Graph& graph)
{
SamplingRegion samplingRegion("DFG Constant Hoisting Phase");
return runPhase<ConstantHoistingPhase>(graph);
}
} }
#endif // ENABLE(DFG_JIT)