void checkOperand(
BlockIndex blockIndex, Operands<size_t>& getLocalPositions,
Operands<size_t>& setLocalPositions, int operand)
{
if (getLocalPositions.operand(operand) == notSet)
return;
if (setLocalPositions.operand(operand) == notSet)
return;
BasicBlock* block = m_graph.m_blocks[blockIndex].get();
VALIDATE(
(block->at(getLocalPositions.operand(operand)),
block->at(setLocalPositions.operand(operand)),
blockIndex),
getLocalPositions.operand(operand) < setLocalPositions.operand(operand));
}
bool run()
{
ASSERT(m_graph.m_form == SSA);
for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
block->ssa->availabilityAtHead.fill(Availability());
block->ssa->availabilityAtTail.fill(Availability());
}
BasicBlock* root = m_graph.block(0);
for (unsigned argument = root->ssa->availabilityAtHead.numberOfArguments(); argument--;) {
root->ssa->availabilityAtHead.argument(argument) =
Availability::unavailable().withFlush(
FlushedAt(FlushedJSValue, virtualRegisterForArgument(argument)));
}
for (unsigned local = root->ssa->availabilityAtHead.numberOfLocals(); local--;)
root->ssa->availabilityAtHead.local(local) = Availability::unavailable();
if (m_graph.m_plan.mode == FTLForOSREntryMode) {
for (unsigned local = m_graph.m_profiledBlock->m_numCalleeRegisters; local--;) {
root->ssa->availabilityAtHead.local(local) =
Availability::unavailable().withFlush(
FlushedAt(FlushedJSValue, virtualRegisterForLocal(local)));
}
}
// This could be made more efficient by processing blocks in reverse postorder.
Operands<Availability> availability;
bool changed;
do {
changed = false;
for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
availability = block->ssa->availabilityAtHead;
for (unsigned nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex) {
Node* node = block->at(nodeIndex);
switch (node->op()) {
case SetLocal: {
VariableAccessData* variable = node->variableAccessData();
availability.operand(variable->local()) =
Availability(node->child1().node(), variable->flushedAt());
break;
}
case GetArgument: {
VariableAccessData* variable = node->variableAccessData();
availability.operand(variable->local()) =
Availability(node, variable->flushedAt());
break;
}
case MovHint:
case MovHintAndCheck: {
VariableAccessData* variable = node->variableAccessData();
availability.operand(variable->local()) =
Availability(node->child1().node());
break;
}
case ZombieHint: {
VariableAccessData* variable = node->variableAccessData();
availability.operand(variable->local()) = Availability::unavailable();
break;
}
default:
break;
}
}
if (availability == block->ssa->availabilityAtTail)
continue;
block->ssa->availabilityAtTail = availability;
changed = true;
for (unsigned successorIndex = block->numSuccessors(); successorIndex--;) {
BasicBlock* successor = block->successor(successorIndex);
for (unsigned i = availability.size(); i--;) {
successor->ssa->availabilityAtHead[i] = availability[i].merge(
successor->ssa->availabilityAtHead[i]);
}
}
}
} while (changed);
return true;
}
