bool run()
{
ASSERT(m_graph.m_form != SSA);
BlockSet blocksThatNeedInvalidationPoints;
for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
for (unsigned nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex)
handle(nodeIndex, block->at(nodeIndex));
// Note: this assumes that control flow occurs at bytecode instruction boundaries.
if (m_originThatHadFire.isSet()) {
for (unsigned i = block->numSuccessors(); i--;)
blocksThatNeedInvalidationPoints.add(block->successor(i));
}
m_insertionSet.execute(block);
}
for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
BasicBlock* block = m_graph.block(blockIndex);
if (!blocksThatNeedInvalidationPoints.contains(block))
continue;
insertInvalidationCheck(0, block->at(0));
m_insertionSet.execute(block);
}
return true;
}
bool isValidFlushLocation(BasicBlock* startingBlock, unsigned index, VirtualRegister operand)
{
// This code is not meant to be fast. We just use it for assertions. If we got liveness wrong,
// this function would return false for a Flush that we insert.
Vector<BasicBlock*, 4> worklist;
BlockSet seen;
auto addPredecessors = [&] (BasicBlock* block) {
for (BasicBlock* predecessor : block->predecessors) {
bool isNewEntry = seen.add(predecessor);
if (isNewEntry)
worklist.append(predecessor);
}
};
auto flushIsDefinitelyInvalid = [&] (BasicBlock* block, unsigned index) {
bool allGood = false;
for (unsigned i = index; i--; ) {
if (block->at(i)->accessesStack(m_graph) && block->at(i)->local() == operand) {
allGood = true;
break;
}
}
if (allGood)
return false;
if (block->predecessors.isEmpty()) {
// This is a root block. We proved we reached here, therefore we can't Flush, as
// it'll make this local live at the start of a root block, which is invalid IR.
return true;
}
addPredecessors(block);
return false;
};
if (flushIsDefinitelyInvalid(startingBlock, index))
return false;
while (!worklist.isEmpty()) {
BasicBlock* block = worklist.takeLast();
if (flushIsDefinitelyInvalid(block, block->size()))
return false;
}
return true;
}