// Eagerly visiting all used conformances leads to a large blowup
// in the amount of SIL we read in. For optimization purposes we can defer
// reading in most conformances until we need them for devirtualization.
// However, we *must* pull in shared clang-importer-derived conformances
// we potentially use, since we may not otherwise have a local definition.
static bool mustDeserializeProtocolConformance(SILModule &M,
ProtocolConformanceRef c) {
if (!c.isConcrete())
return false;
auto conformance = c.getConcrete()->getRootNormalConformance();
return M.Types.protocolRequiresWitnessTable(conformance->getProtocol())
&& isa<ClangModuleUnit>(conformance->getDeclContext()
->getModuleScopeContext());
}
std::pair<SILWitnessTable *, ArrayRef<Substitution>>
SILModule::
lookUpWitnessTable(ProtocolConformanceRef C, bool deserializeLazily) {
// If we have an abstract conformance passed in (a legal value), just return
// nullptr.
if (!C.isConcrete())
return {nullptr, {}};
return lookUpWitnessTable(C.getConcrete());
}
Type TypeChecker::getWitnessType(Type type, ProtocolDecl *protocol,
ProtocolConformanceRef conformance,
Identifier name,
Diag<> brokenProtocolDiag) {
Type ty = ProtocolConformance::getTypeWitnessByName(type, conformance,
name, this);
if (!ty &&
!(conformance.isConcrete() && conformance.getConcrete()->isInvalid()))
diagnose(protocol->getLoc(), brokenProtocolDiag);
return ty;
}