DFGSSALoweringPhase.cpp [plain text]
#include "config.h"
#include "DFGSSALoweringPhase.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 SSALoweringPhase : public Phase {
static const bool verbose = false;
public:
SSALoweringPhase(Graph& graph)
: Phase(graph, "SSA lowering")
, m_insertionSet(graph)
{
}
bool run()
{
RELEASE_ASSERT(m_graph.m_form == SSA);
for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
m_block = m_graph.block(blockIndex);
if (!m_block)
continue;
for (m_nodeIndex = 0; m_nodeIndex < m_block->size(); ++m_nodeIndex) {
m_node = m_block->at(m_nodeIndex);
handleNode();
}
m_insertionSet.execute(m_block);
}
return true;
}
private:
void handleNode()
{
switch (m_node->op()) {
case GetByVal:
lowerBoundsCheck(m_node->child1(), m_node->child2(), m_node->child3());
break;
case PutByVal:
case PutByValDirect: {
Edge base = m_graph.varArgChild(m_node, 0);
Edge index = m_graph.varArgChild(m_node, 1);
Edge storage = m_graph.varArgChild(m_node, 3);
if (lowerBoundsCheck(base, index, storage))
break;
if (m_node->arrayMode().typedArrayType() != NotTypedArray && m_node->arrayMode().isOutOfBounds()) {
Node* length = m_insertionSet.insertNode(
m_nodeIndex, SpecInt32, GetArrayLength, m_node->origin,
OpInfo(m_node->arrayMode().asWord()), base, storage);
m_graph.varArgChild(m_node, 4) = Edge(length, KnownInt32Use);
break;
}
break;
}
default:
break;
}
}
bool lowerBoundsCheck(Edge base, Edge index, Edge storage)
{
if (!m_node->arrayMode().permitsBoundsCheckLowering())
return false;
if (!m_node->arrayMode().lengthNeedsStorage())
storage = Edge();
Node* length = m_insertionSet.insertNode(
m_nodeIndex, SpecInt32, GetArrayLength, m_node->origin,
OpInfo(m_node->arrayMode().asWord()), base, storage);
m_insertionSet.insertNode(
m_nodeIndex, SpecInt32, CheckInBounds, m_node->origin,
index, Edge(length, KnownInt32Use));
return true;
}
InsertionSet m_insertionSet;
BasicBlock* m_block;
unsigned m_nodeIndex;
Node* m_node;
};
bool performSSALowering(Graph& graph)
{
SamplingRegion samplingRegion("DFG SSA Lowering Phase");
return runPhase<SSALoweringPhase>(graph);
}
} }
#endif // ENABLE(DFG_JIT)