DFGCriticalEdgeBreakingPhase.cpp [plain text]
#include "config.h"
#include "DFGCriticalEdgeBreakingPhase.h"
#if ENABLE(DFG_JIT)
#include "DFGBasicBlockInlines.h"
#include "DFGBlockInsertionSet.h"
#include "DFGGraph.h"
#include "DFGPhase.h"
#include "JSCJSValueInlines.h"
namespace JSC { namespace DFG {
class CriticalEdgeBreakingPhase : public Phase {
public:
CriticalEdgeBreakingPhase(Graph& graph)
: Phase(graph, "critical edge breaking")
, m_insertionSet(graph)
{
}
bool run()
{
for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
if (block->numSuccessors() <= 1)
continue;
HashMap<BasicBlock*, BasicBlock*> successorPads;
for (unsigned i = block->numSuccessors(); i--;) {
BasicBlock** successor = &block->successor(i);
if ((*successor)->predecessors.size() <= 1)
continue;
BasicBlock* pad = nullptr;
auto iter = successorPads.find(*successor);
if (iter == successorPads.end()) {
pad = m_insertionSet.insertBefore(*successor, (*successor)->executionCount);
pad->appendNode(
m_graph, SpecNone, Jump, (*successor)->at(0)->origin, OpInfo(*successor));
pad->predecessors.append(block);
(*successor)->replacePredecessor(block, pad);
successorPads.set(*successor, pad);
} else
pad = iter->value;
*successor = pad;
}
}
return m_insertionSet.execute();
}
private:
BlockInsertionSet m_insertionSet;
};
bool performCriticalEdgeBreaking(Graph& graph)
{
return runPhase<CriticalEdgeBreakingPhase>(graph);
}
} }
#endif // ENABLE(DFG_JIT)