#include "config.h"
#include "DFGDominators.h"
#if ENABLE(DFG_JIT)
#include "DFGGraph.h"
#include "JSCInlines.h"
namespace JSC { namespace DFG {
Dominators::Dominators()
{
}
Dominators::~Dominators()
{
}
void Dominators::compute(Graph& graph)
{
ASSERT(graph.block(0)->predecessors.isEmpty());
unsigned numBlocks = graph.numBlocks();
if (numBlocks > m_results.size()) {
m_results.grow(numBlocks);
for (unsigned i = numBlocks; i--;)
m_results[i].resize(numBlocks);
m_scratch.resize(numBlocks);
}
m_results[0].clearAll();
m_results[0].set(0);
m_scratch.clearAll();
for (unsigned i = numBlocks; i--;) {
if (!graph.block(i))
continue;
m_scratch.set(i);
}
for (unsigned i = numBlocks; i-- > 1;) {
if (!graph.block(i) || graph.block(i)->predecessors.isEmpty())
m_results[i].clearAll();
else
m_results[i].set(m_scratch);
}
bool changed;
do {
changed = false;
for (unsigned i = 1; i < numBlocks; ++i)
changed |= pruneDominators(graph, i);
if (!changed)
break;
changed = false;
for (unsigned i = numBlocks; i-- > 1;)
changed |= pruneDominators(graph, i);
} while (changed);
}
bool Dominators::pruneDominators(Graph& graph, BlockIndex idx)
{
BasicBlock* block = graph.block(idx);
if (!block || block->predecessors.isEmpty())
return false;
m_scratch.set(m_results[block->predecessors[0]->index]);
for (unsigned j = block->predecessors.size(); j-- > 1;)
m_scratch.filter(m_results[block->predecessors[j]->index]);
m_scratch.set(idx);
return m_results[idx].setAndCheck(m_scratch);
}
void Dominators::dump(Graph& graph, PrintStream& out) const
{
for (BlockIndex blockIndex = 0; blockIndex < graph.numBlocks(); ++blockIndex) {
BasicBlock* block = graph.block(blockIndex);
if (!block)
continue;
out.print(" Block ", *block, ":");
for (BlockIndex otherIndex = 0; otherIndex < graph.numBlocks(); ++otherIndex) {
if (!dominates(block->index, otherIndex))
continue;
out.print(" #", otherIndex);
}
out.print("\n");
}
}
} }
#endif // ENABLE(DFG_JIT)