SSATmp* TraceBuilder::preOptimizeAssertLoc(IRInstruction* inst) {
auto const locId = inst->extra<AssertLoc>()->locId;
auto const prevType = localType(locId, DataTypeGeneric);
auto const typeParam = inst->typeParam();
if (prevType.not(typeParam)) {
/* Task #2553746
* This is triggering for a case where the tracked state says the local is
* InitNull but the AssertLoc says it's Str. */
static auto const error =
makeStaticString("Internal error: static analysis was "
"wrong about a local variable's type.");
auto* errorInst = m_unit.gen(RaiseError, inst->marker(), cns(error));
inst->become(m_unit, errorInst);
// It's not a disaster to generate this in unreachable code for
// now. t2590033.
if (false) {
assert_log(false, [&]{
return folly::format("\npreOptimizeAssertLoc: prevType: {} "
"typeParam: {}\nin instr: {}\nin trace: {}\n",
prevType.toString(),
typeParam.toString(),
inst->toString(),
m_unit.main()->toString()).str();
});
}
} else if (shouldElideAssertType(prevType, typeParam, nullptr)) {
// The type we're asserting is worse than the last known type.
return inst->src(0);
}
return nullptr;
}
SSATmp* TraceBuilder::preOptimizeAssertLoc(IRInstruction* inst) {
auto const locId = inst->extra<AssertLoc>()->locId;
auto const prevType = localType(locId, DataTypeGeneric);
auto const typeParam = inst->typeParam();
if (prevType.not(typeParam)) {
TRACE_PUNT("Invalid AssertLoc");
}
if (shouldElideAssertType(prevType, typeParam, nullptr)) {
return inst->src(0);
}
if (filterAssertType(inst, prevType)) {
constrainLocal(locId, categoryForType(prevType), "AssertLoc");
}
return nullptr;
}