int ConformanceLookupTable::compareProtocolConformances(
ProtocolConformance * const *lhsPtr,
ProtocolConformance * const *rhsPtr) {
ProtocolConformance *lhs = *lhsPtr;
ProtocolConformance *rhs = *rhsPtr;
// If the two conformances are normal conformances with locations,
// sort by location.
if (auto lhsNormal = dyn_cast<NormalProtocolConformance>(lhs)) {
if (auto rhsNormal = dyn_cast<NormalProtocolConformance>(rhs)) {
if (lhsNormal->getLoc().isValid() && rhsNormal->getLoc().isValid()) {
ASTContext &ctx = lhs->getDeclContext()->getASTContext();
unsigned lhsBuffer
= ctx.SourceMgr.findBufferContainingLoc(lhsNormal->getLoc());
unsigned rhsBuffer
= ctx.SourceMgr.findBufferContainingLoc(rhsNormal->getLoc());
// If the buffers are the same, use source location ordering.
if (lhsBuffer == rhsBuffer) {
return ctx.SourceMgr.isBeforeInBuffer(lhsNormal->getLoc(),
rhsNormal->getLoc());
}
// Otherwise, order by buffer identifier.
return StringRef(ctx.SourceMgr.getIdentifierForBuffer(lhsBuffer))
.compare(ctx.SourceMgr.getIdentifierForBuffer(rhsBuffer));
}
}
}
// Otherwise, sort by protocol.
ProtocolDecl *lhsProto = lhs->getProtocol();
ProtocolDecl *rhsProto = rhs->getProtocol();
return ProtocolType::compareProtocols(&lhsProto, &rhsProto);
}
void layout() {
// If the conforming type is generic, we just want to emit the
// unbound generic type here.
auto *Nominal = Conformance->getInterfaceType()->getAnyNominal();
assert(Nominal && "Structural conformance?");
PrettyStackTraceDecl DebugStack("emitting associated type metadata",
Nominal);
auto *M = IGM.getSILModule().getSwiftModule();
addTypeRef(M, Nominal->getDeclaredType()->getCanonicalType());
auto ProtoTy = Conformance->getProtocol()->getDeclaredType();
addTypeRef(M, ProtoTy->getCanonicalType());
addConstantInt32(AssociatedTypes.size());
addConstantInt32(AssociatedTypeRecordSize);
for (auto AssocTy : AssociatedTypes) {
auto NameGlobal = IGM.getAddrOfStringForTypeRef(AssocTy.first);
addRelativeAddress(NameGlobal);
addBuiltinTypeRefs(AssocTy.second);
addTypeRef(M, AssocTy.second);
}
}
/// Compare two declarations to determine whether one is a witness of the other.
static Comparison compareWitnessAndRequirement(TypeChecker &tc, DeclContext *dc,
ValueDecl *decl1,
ValueDecl *decl2) {
// We only have a witness/requirement pair if exactly one of the declarations
// comes from a protocol.
auto proto1 = dyn_cast<ProtocolDecl>(decl1->getDeclContext());
auto proto2 = dyn_cast<ProtocolDecl>(decl2->getDeclContext());
if ((bool)proto1 == (bool)proto2)
return Comparison::Unordered;
// Figure out the protocol, requirement, and potential witness.
ProtocolDecl *proto;
ValueDecl *req;
ValueDecl *potentialWitness;
if (proto1) {
proto = proto1;
req = decl1;
potentialWitness = decl2;
} else {
proto = proto2;
req = decl2;
potentialWitness = decl1;
}
// Cannot compare type declarations this way.
// FIXME: Use the same type-substitution approach as lookupMemberType.
if (isa<TypeDecl>(req))
return Comparison::Unordered;
if (!potentialWitness->getDeclContext()->isTypeContext())
return Comparison::Unordered;
// Determine whether the type of the witness's context conforms to the
// protocol.
auto owningType
= potentialWitness->getDeclContext()->getDeclaredTypeInContext();
ProtocolConformance *conformance = nullptr;
if (!tc.conformsToProtocol(owningType, proto, dc,
ConformanceCheckFlags::InExpression, &conformance) ||
!conformance)
return Comparison::Unordered;
// If the witness and the potential witness are not the same, there's no
// ordering here.
if (conformance->getWitness(req, &tc).getDecl() != potentialWitness)
return Comparison::Unordered;
// We have a requirement/witness match.
return proto1? Comparison::Worse : Comparison::Better;
}
void layout() override {
// If the conforming type is generic, we just want to emit the
// unbound generic type here.
auto *Nominal = Conformance->getType()->getAnyNominal();
assert(Nominal && "Structural conformance?");
PrettyStackTraceDecl DebugStack("emitting associated type metadata",
Nominal);
addTypeRef(Nominal->getDeclaredType()->getCanonicalType());
addNominalRef(Conformance->getProtocol());
B.addInt32(AssociatedTypes.size());
B.addInt32(AssociatedTypeRecordSize);
for (auto AssocTy : AssociatedTypes) {
auto NameGlobal = IGM.getAddrOfFieldName(AssocTy.first);
B.addRelativeAddress(NameGlobal);
addBuiltinTypeRefs(AssocTy.second);
addTypeRef(AssocTy.second);
}
}
LookupTypeResult TypeChecker::lookupMemberType(DeclContext *dc,
Type type, Identifier name,
NameLookupOptions options) {
LookupTypeResult result;
// Look through an inout type.
if (auto inout = type->getAs<InOutType>())
type = inout->getObjectType();
// Look through the metatype.
if (auto metaT = type->getAs<AnyMetatypeType>())
type = metaT->getInstanceType();
// Callers must cope with dependent types directly.
assert(!type->isTypeParameter());
// Look for members with the given name.
SmallVector<ValueDecl *, 4> decls;
NLOptions subOptions = NL_QualifiedDefault | NL_OnlyTypes;
if (options.contains(NameLookupFlags::KnownPrivate))
subOptions |= NL_KnownNonCascadingDependency;
if (options.contains(NameLookupFlags::ProtocolMembers))
subOptions |= NL_ProtocolMembers;
if (options.contains(NameLookupFlags::IgnoreAccessibility))
subOptions |= NL_IgnoreAccessibility;
if (!dc->lookupQualified(type, name, subOptions, this, decls))
return result;
// Look through the declarations, keeping only the unique type declarations.
llvm::SmallPtrSet<CanType, 4> types;
SmallVector<AssociatedTypeDecl *, 4> inferredAssociatedTypes;
for (auto decl : decls) {
auto *typeDecl = cast<TypeDecl>(decl);
// FIXME: This should happen before we attempt shadowing checks.
validateDecl(typeDecl);
if (!typeDecl->hasType()) // FIXME: recursion-breaking hack
continue;
// If we're looking up a member of a protocol, we must take special care.
if (typeDecl->getDeclContext()->getAsProtocolOrProtocolExtensionContext()) {
// We don't allow lookups of an associated type or typealias of an
// existential type, because we have no way to represent such types.
//
// This is diagnosed further on down in resolveNestedIdentTypeComponent().
if (type->isExistentialType()) {
auto memberType = typeDecl->getInterfaceType()->getRValueInstanceType();
if (memberType->hasTypeParameter()) {
// If we haven't seen this type result yet, add it to the result set.
if (types.insert(memberType->getCanonicalType()).second)
result.Results.push_back({typeDecl, memberType});
continue;
}
}
// If we're looking up an associated type of a concrete type,
// record it later for conformance checking; we might find a more
// direct typealias with the same name later.
if (auto assocType = dyn_cast<AssociatedTypeDecl>(typeDecl)) {
if (!type->is<ArchetypeType>()) {
inferredAssociatedTypes.push_back(assocType);
continue;
}
}
// We are looking up an associated type of an archetype, or a
// protocol typealias or an archetype or concrete type.
//
// Proceed with the usual path below.
}
// Substitute the base into the member's type.
auto memberType = substMemberTypeWithBase(dc->getParentModule(),
typeDecl, type,
/*isTypeReference=*/true);
// FIXME: It is not clear why this substitution can fail, but the
// standard library won't build without this check.
if (!memberType)
continue;
// If we haven't seen this type result yet, add it to the result set.
if (types.insert(memberType->getCanonicalType()).second)
result.Results.push_back({typeDecl, memberType});
}
if (result.Results.empty()) {
// We couldn't find any normal declarations. Let's try inferring
// associated types.
ConformanceCheckOptions conformanceOptions;
if (options.contains(NameLookupFlags::KnownPrivate))
conformanceOptions |= ConformanceCheckFlags::InExpression;
for (AssociatedTypeDecl *assocType : inferredAssociatedTypes) {
// If the type does not actually conform to the protocol, skip this
// member entirely.
auto *protocol = cast<ProtocolDecl>(assocType->getDeclContext());
ProtocolConformance *conformance = nullptr;
if (!conformsToProtocol(type, protocol, dc, conformanceOptions,
&conformance) ||
!conformance) {
// FIXME: This is an error path. Should we try to recover?
continue;
}
// Use the type witness.
Type memberType =
conformance->getTypeWitness(assocType, this).getReplacement();
assert(memberType && "Missing type witness?");
// If we haven't seen this type result yet, add it to the result set.
if (types.insert(memberType->getCanonicalType()).second)
result.Results.push_back({assocType, memberType});
}
}
return result;
}
LookupTypeResult TypeChecker::lookupMemberType(DeclContext *dc,
Type type, Identifier name,
NameLookupOptions options) {
LookupTypeResult result;
// Look through an inout type.
if (auto inout = type->getAs<InOutType>())
type = inout->getObjectType();
// Look through the metatype.
if (auto metaT = type->getAs<AnyMetatypeType>())
type = metaT->getInstanceType();
// Callers must cope with dependent types directly.
assert(!type->isTypeParameter());
// Look for members with the given name.
SmallVector<ValueDecl *, 4> decls;
NLOptions subOptions = NL_QualifiedDefault;
if (options.contains(NameLookupFlags::KnownPrivate))
subOptions |= NL_KnownNonCascadingDependency;
if (options.contains(NameLookupFlags::ProtocolMembers))
subOptions |= NL_ProtocolMembers;
if (options.contains(NameLookupFlags::IgnoreAccessibility))
subOptions |= NL_IgnoreAccessibility;
if (!dc->lookupQualified(type, name, subOptions, this, decls))
return result;
// Look through the declarations, keeping only the unique type declarations.
llvm::SmallPtrSet<CanType, 4> types;
SmallVector<AssociatedTypeDecl *, 4> inferredAssociatedTypes;
for (auto decl : decls) {
// Ignore non-types found by name lookup.
auto typeDecl = dyn_cast<TypeDecl>(decl);
if (!typeDecl)
continue;
// FIXME: This should happen before we attempt shadowing checks.
validateDecl(typeDecl);
if (!typeDecl->hasType()) // FIXME: recursion-breaking hack
continue;
// If we found a member of a protocol type when looking into a non-protocol,
// non-archetype type, only include this member in the result set if
// this member was used as the default definition or otherwise inferred.
if (auto assocType = dyn_cast<AssociatedTypeDecl>(typeDecl)) {
if (!type->is<ArchetypeType>() && !type->isExistentialType()) {
inferredAssociatedTypes.push_back(assocType);
continue;
}
}
// Ignore typealiases found in protocol members.
if (auto alias = dyn_cast<TypeAliasDecl>(typeDecl)) {
auto aliasParent = alias->getParent();
if (aliasParent != dc && isa<ProtocolDecl>(aliasParent))
continue;
}
// Substitute the base into the member's type.
if (Type memberType = substMemberTypeWithBase(dc->getParentModule(),
typeDecl, type,
/*isTypeReference=*/true)) {
// If we haven't seen this type result yet, add it to the result set.
if (types.insert(memberType->getCanonicalType()).second)
result.Results.push_back({typeDecl, memberType});
}
}
if (result.Results.empty()) {
// We couldn't find any normal declarations. Let's try inferring
// associated types.
ConformanceCheckOptions conformanceOptions;
if (options.contains(NameLookupFlags::KnownPrivate))
conformanceOptions |= ConformanceCheckFlags::InExpression;
for (AssociatedTypeDecl *assocType : inferredAssociatedTypes) {
// If the type does not actually conform to the protocol, skip this
// member entirely.
auto *protocol = cast<ProtocolDecl>(assocType->getDeclContext());
ProtocolConformance *conformance = nullptr;
if (!conformsToProtocol(type, protocol, dc, conformanceOptions,
&conformance) ||
!conformance) {
// FIXME: This is an error path. Should we try to recover?
continue;
}
// Use the type witness.
Type memberType =
conformance->getTypeWitness(assocType, this).getReplacement();
assert(memberType && "Missing type witness?");
// If we haven't seen this type result yet, add it to the result set.
if (types.insert(memberType->getCanonicalType()).second)
result.Results.push_back({assocType, memberType});
}
}
return result;
}
ProtocolConformance *
ProtocolConformance::getInheritedConformance(ProtocolDecl *protocol) const {
// Preserve specialization through this operation by peeling off the
// substitutions from a specialized conformance so we can apply them later.
const ProtocolConformance *unspecialized;
SubstitutionIterator subs;
switch (getKind()) {
case ProtocolConformanceKind::Specialized: {
auto spec = cast<SpecializedProtocolConformance>(this);
unspecialized = spec->getGenericConformance();
subs = spec->getGenericSubstitutionIterator();
break;
}
case ProtocolConformanceKind::Normal:
case ProtocolConformanceKind::Inherited:
unspecialized = this;
break;
}
ProtocolConformance *foundInherited;
// Search for the inherited conformance among our immediate parents.
auto &inherited = unspecialized->getInheritedConformances();
auto known = inherited.find(protocol);
if (known != inherited.end()) {
foundInherited = known->second;
goto found_inherited;
}
// If not there, the inherited conformance must be available through one of
// our parents.
for (auto &inheritedMapping : inherited)
if (inheritedMapping.first->inheritsFrom(protocol)) {
foundInherited = inheritedMapping.second->
getInheritedConformance(protocol);
goto found_inherited;
}
llvm_unreachable("Can't find the inherited conformance.");
found_inherited:
// Specialize the inherited conformance, if necessary.
if (!subs.empty()) {
TypeSubstitutionMap subMap;
ArchetypeConformanceMap conformanceMap;
// Fill in the substitution and conformance maps.
for (auto archAndSub : subs) {
auto arch = archAndSub.first;
auto sub = archAndSub.second;
conformanceMap[arch] = sub.getConformances();
if (arch->isPrimary())
subMap[arch] = sub.getReplacement();
}
return foundInherited->subst(getDeclContext()->getParentModule(),
getType(), subs.getSubstitutions(),
subMap, conformanceMap);
}
assert((getType()->isEqual(foundInherited->getType()) ||
foundInherited->getType()->isSuperclassOf(getType(), nullptr))
&& "inherited conformance does not match type");
return foundInherited;
}
