/*
* Compute the stack and local type postconditions for a
* single-entry/single-exit tracelet.
*/
std::vector<RegionDesc::TypePred> IRBuilder::getKnownTypes() {
// This function is only correct when given a single-exit region, as
// in TransProfile. Furthermore, its output is only used to guide
// formation of profile-driven regions.
assert(tx->mode() == TransProfile);
// We want the state for the last block on the "main trace". Figure
// out which that is.
Block* mainExit = nullptr;
for (auto* b : rpoSortCfg(m_unit)) {
if (isMainExit(b)) {
assert(mainExit == nullptr);
mainExit = b;
}
}
assert(mainExit != nullptr);
// Load state for mainExit. This feels hacky.
FTRACE(1, "mainExit: B{}\n", mainExit->id());
m_state.startBlock(mainExit);
// Now use the current state to get all the types.
std::vector<RegionDesc::TypePred> result;
auto const curFunc = m_state.func();
auto const sp = m_state.sp();
auto const spOffset = m_state.spOffset();
for (unsigned i = 0; i < curFunc->maxStackCells(); ++i) {
auto t = getStackValue(sp, i).knownType;
if (!t.equals(Type::StackElem)) {
result.push_back({ RegionDesc::Location::Stack{i, spOffset - i}, t });
}
}
for (unsigned i = 0; i < curFunc->numLocals(); ++i) {
auto t = m_state.localType(i);
if (!t.equals(Type::Gen)) {
FTRACE(1, "Local {}: {}\n", i, t.toString());
result.push_back({ RegionDesc::Location::Local{i}, t });
}
}
return result;
}
/*
* Intended to be called after all optimizations are finished on a
* single-entry, single-exit tracelet, this collects the types of all stack
* slots and locals at the end of the main exit.
*/
void IRUnit::collectPostConditions() {
// This function is only correct when given a single-exit region, as in
// TransKind::Profile. Furthermore, its output is only used to guide
// formation of profile-driven regions.
assert(mcg->tx().mode() == TransKind::Profile);
assert(m_postConds.empty());
Timer _t(Timer::collectPostConditions);
// We want the state for the last block on the "main trace". Figure
// out which that is.
Block* mainExit = nullptr;
Block* lastMainBlock = nullptr;
FrameStateMgr state{*this, entry()->front().marker()};
// TODO(#5678127): this code is wrong for HHIRBytecodeControlFlow
state.setLegacyReoptimize();
ITRACE(2, "collectPostConditions starting\n");
Trace::Indent _i;
for (auto* block : rpoSortCfg(*this)) {
state.startBlock(block, block->front().marker());
for (auto& inst : *block) {
state.update(&inst);
}
if (isMainBlock(block)) lastMainBlock = block;
if (isMainExit(block)) {
mainExit = block;
break;
}
state.finishBlock(block);
}
// If we didn't find an obvious exit, then use the last block in the region.
always_assert(lastMainBlock != nullptr);
if (mainExit == nullptr) mainExit = lastMainBlock;
FTRACE(1, "mainExit: B{}\n", mainExit->id());
// state currently holds the state at the end of mainExit
auto const curFunc = state.func();
auto const sp = state.sp();
auto const spOffset = state.spOffset();
for (unsigned i = 0; i < spOffset; ++i) {
auto t = getStackValue(sp, i).knownType;
if (!t.equals(Type::StackElem)) {
m_postConds.push_back({ RegionDesc::Location::Stack{i, spOffset - i},
t });
}
}
for (unsigned i = 0; i < curFunc->numLocals(); ++i) {
auto t = state.localType(i);
if (!t.equals(Type::Gen)) {
FTRACE(1, "Local {}: {}\n", i, t.toString());
m_postConds.push_back({ RegionDesc::Location::Local{i}, t });
}
}
}