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[GSB] Centralize lookup of nested types.

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We had two similar loops that performed name lookup for nested types on a
potential archetype, so consolidate those into a single implementation on
the equivalence class itself.
This commit is contained in:
Doug Gregor
2017-09-21 15:14:11 -07:00
parent da56cb33b8
commit 9bdeff2e3d
2 changed files with 151 additions and 130 deletions
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273
lib/AST/GenericSignatureBuilder.cpp
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@@ -1554,6 +1554,129 @@ bool EquivalenceClass::isConformanceSatisfiedBySuperclass(
return false;
}
/// Compare two associated types.
static int compareAssociatedTypes(AssociatedTypeDecl *assocType1,
AssociatedTypeDecl *assocType2) {
// - by name.
if (int result = assocType1->getName().str().compare(
assocType2->getName().str()))
return result;
// - by protocol, so t_n_m.`P.T` < t_n_m.`Q.T` (given P < Q)
auto proto1 = assocType1->getProtocol();
auto proto2 = assocType2->getProtocol();
if (int compareProtocols = ProtocolType::compareProtocols(&proto1, &proto2))
return compareProtocols;
// Error case: if we have two associated types with the same name in the
// same protocol, just tie-break based on address.
if (assocType1 != assocType2)
return assocType1 < assocType2 ? -1 : +1;
return 0;
}
TypeDecl *EquivalenceClass::lookupNestedType(
Identifier name,
SmallVectorImpl<TypeDecl *> *otherConcreteTypes) {
// Look for types with the given name in protocols that we know about.
AssociatedTypeDecl *bestAssocType = nullptr;
SmallVector<TypeDecl *, 4> concreteDecls;
for (const auto &conforms : conformsTo) {
ProtocolDecl *proto = conforms.first;
// Look for an associated type and/or concrete type with this name.
for (auto member : proto->lookupDirect(name,
/*ignoreNewExtensions=*/true)) {
// If this is an associated type, record whether it is the best
// associated type we've seen thus far.
if (auto assocType = dyn_cast<AssociatedTypeDecl>(member)) {
if (!bestAssocType ||
compareAssociatedTypes(assocType, bestAssocType) < 0)
bestAssocType = assocType;
continue;
}
// If this is another type declaration, determine whether we should
// record it.
if (auto type = dyn_cast<TypeDecl>(member)) {
// FIXME: Filter out type declarations that aren't in the same
// module as the protocol itself. This is an unprincipled hack, but
// provides consistent lookup semantics for the generic signature
// builder in all contents.
if (type->getDeclContext()->getParentModule()
!= proto->getParentModule())
continue;
// Resolve the signature of this type.
if (!type->hasInterfaceType()) {
type->getASTContext().getLazyResolver()->resolveDeclSignature(type);
if (!type->hasInterfaceType())
continue;
}
concreteDecls.push_back(type);
continue;
}
}
}
// If we haven't found anything yet but have a superclass, look for a type
// in the superclass.
// FIXME: Shouldn't we always look in the superclass?
if (!bestAssocType && concreteDecls.empty() && superclass) {
if (auto classDecl = superclass->getClassOrBoundGenericClass()) {
SmallVector<ValueDecl *, 2> superclassMembers;
classDecl->getParentModule()->lookupQualified(
superclass, name,
NL_QualifiedDefault | NL_OnlyTypes | NL_ProtocolMembers, nullptr,
superclassMembers);
for (auto member : superclassMembers) {
if (auto type = dyn_cast<TypeDecl>(member)) {
// Resolve the signature of this type.
if (!type->hasInterfaceType()) {
type->getASTContext().getLazyResolver()->resolveDeclSignature(type);
if (!type->hasInterfaceType())
continue;
}
concreteDecls.push_back(type);
}
}
}
}
// If we have an associated type, that's our result.
if (bestAssocType) {
// Populate the list of concrete types, if requested.
if (otherConcreteTypes)
otherConcreteTypes->assign(concreteDecls.begin(), concreteDecls.end());
return bestAssocType;
}
// If there were no concrete types either, lookup failed.
if (concreteDecls.empty())
return nullptr;
// Find the best concrete type.
auto bestConcreteTypeIter =
std::min_element(concreteDecls.begin(), concreteDecls.end(),
[](TypeDecl *type1, TypeDecl *type2) {
return TypeDecl::compare(type1, type2) < 0;
});
// If were asked to provide all of the concrete types, do so now.
if (otherConcreteTypes) {
otherConcreteTypes->assign(concreteDecls.begin(), bestConcreteTypeIter);
otherConcreteTypes->insert(otherConcreteTypes->end(),
bestConcreteTypeIter + 1, concreteDecls.end());
}
return *bestConcreteTypeIter;
}
void EquivalenceClass::dump(llvm::raw_ostream &out) const {
out << "Equivalence class represented by "
<< members.front()->getRepresentative()->getDebugName() << ":\n";
@@ -1961,28 +2084,6 @@ auto PotentialArchetype::getRepresentative() const -> PotentialArchetype * {
return result;
}
/// Compare two associated types.
static int compareAssociatedTypes(AssociatedTypeDecl *assocType1,
AssociatedTypeDecl *assocType2) {
// - by name.
if (int result = assocType1->getName().str().compare(
assocType2->getName().str()))
return result;
// - by protocol, so t_n_m.`P.T` < t_n_m.`Q.T` (given P < Q)
auto proto1 = assocType1->getProtocol();
auto proto2 = assocType2->getProtocol();
if (int compareProtocols = ProtocolType::compareProtocols(&proto1, &proto2))
return compareProtocols;
// Error case: if we have two associated types with the same name in the
// same protocol, just tie-break based on address.
if (assocType1 != assocType2)
return assocType1 < assocType2 ? -1 : +1;
return 0;
}
/// Whether there are any concrete type declarations in the potential archetype.
static bool hasConcreteDecls(const PotentialArchetype *pa) {
auto parent = pa->getParent();
@@ -2227,94 +2328,21 @@ PotentialArchetype *PotentialArchetype::getNestedArchetypeAnchor(
Identifier name,
GenericSignatureBuilder &builder,
ArchetypeResolutionKind kind) {
// Look for the best associated type or concrete type within the protocols
// we know about.
AssociatedTypeDecl *bestAssocType = nullptr;
TypeDecl *bestConcreteDecl = nullptr;
SmallVector<TypeDecl *, 4> concreteDecls;
auto rep = getRepresentative();
for (auto proto : rep->getConformsTo()) {
// Look for an associated type and/or concrete type with this name.
AssociatedTypeDecl *assocType = nullptr;
TypeDecl *concreteDecl = nullptr;
for (auto member : proto->lookupDirect(name,
/*ignoreNewExtensions=*/true)) {
if (!assocType)
assocType = dyn_cast<AssociatedTypeDecl>(member);
auto bestType =
getOrCreateEquivalenceClass()->lookupNestedType(name, &concreteDecls);
// FIXME: Filter out type declarations that aren't in the protocol itself?
if (!concreteDecl && !isa<AssociatedTypeDecl>(member)) {
if (!member->hasInterfaceType())
builder.getLazyResolver()->resolveDeclSignature(member);
if (member->hasInterfaceType())
concreteDecl = dyn_cast<TypeDecl>(member);
}
}
// We didn't find any type with this name.
if (!bestType) return nullptr;
if (assocType &&
(!bestAssocType ||
compareAssociatedTypes(assocType, bestAssocType) < 0))
bestAssocType = assocType;
if (concreteDecl) {
// Record every concrete type.
concreteDecls.push_back(concreteDecl);
// Track the best concrete type.
if (!bestConcreteDecl ||
TypeDecl::compare(concreteDecl, bestConcreteDecl) < 0)
bestConcreteDecl = concreteDecl;
}
}
// If we found an associated type, use it.
PotentialArchetype *resultPA = nullptr;
if (bestAssocType) {
resultPA = updateNestedTypeForConformance(bestAssocType, kind);
}
// If we have an associated type, drop any concrete decls that aren't in
// the same module as the protocol.
// FIXME: This is an unprincipled hack for an unprincipled feature.
concreteDecls.erase(
std::remove_if(concreteDecls.begin(), concreteDecls.end(),
[&](TypeDecl *concreteDecl) {
return concreteDecl->getDeclContext()->getParentModule() !=
concreteDecl->getDeclContext()
->getAsNominalTypeOrNominalTypeExtensionContext()->getParentModule();
}),
concreteDecls.end());
// If we haven't found anything yet but have a superclass, look for a type
// in the superclass.
if (!resultPA && concreteDecls.empty()) {
if (auto superclass = getSuperclass()) {
if (auto classDecl = superclass->getClassOrBoundGenericClass()) {
SmallVector<ValueDecl *, 2> superclassMembers;
classDecl->getParentModule()->lookupQualified(superclass, name, NL_QualifiedDefault | NL_OnlyTypes | NL_ProtocolMembers, nullptr,
superclassMembers);
for (auto member : superclassMembers) {
if (auto concreteDecl = dyn_cast<TypeDecl>(member)) {
// Track the best concrete type.
if (!bestConcreteDecl ||
TypeDecl::compare(concreteDecl, bestConcreteDecl) < 0)
bestConcreteDecl = concreteDecl;
concreteDecls.push_back(concreteDecl);
}
}
}
}
}
// Resolve the nested type.
auto resultPA = updateNestedTypeForConformance(bestType, kind);
// Update for all of the concrete decls with this name, which will introduce
// various same-type constraints.
for (auto concreteDecl : concreteDecls) {
auto concreteDeclPA = updateNestedTypeForConformance(
concreteDecl,
ArchetypeResolutionKind::WellFormed);
if (!resultPA && concreteDecl == bestConcreteDecl)
resultPA = concreteDeclPA;
(void)updateNestedTypeForConformance(concreteDecl,
ArchetypeResolutionKind::WellFormed);
}
return resultPA;
@@ -2325,34 +2353,13 @@ PotentialArchetype *PotentialArchetype::updateNestedTypeForConformance(
Identifier name,
ProtocolDecl *proto,
ArchetypeResolutionKind kind) {
/// Determine whether there is an associated type or concrete type with this
/// name in this protocol. If not, there's nothing to do.
AssociatedTypeDecl *assocType = nullptr;
TypeDecl *concreteDecl = nullptr;
for (auto member : proto->lookupDirect(name, /*ignoreNewExtensions=*/true)) {
if (!assocType)
assocType = dyn_cast<AssociatedTypeDecl>(member);
// Lookup the best type for this name.
auto bestType =
getOrCreateEquivalenceClass()->lookupNestedType(name, nullptr);
if (!bestType) return nullptr;
// FIXME: Filter out concrete types that aren't in the protocol itself?
if (!concreteDecl && !isa<AssociatedTypeDecl>(member)) {
if (!member->hasInterfaceType())
proto->getASTContext().getLazyResolver()->resolveDeclSignature(member);
if (member->hasInterfaceType())
concreteDecl = dyn_cast<TypeDecl>(member);
}
}
// There is no associated type or concrete type with this name in this
// protocol
if (!assocType && !concreteDecl)
return nullptr;
// If we had both an associated type and a concrete type, ignore the latter.
// This is for ill-formed code.
if (assocType)
return updateNestedTypeForConformance(assocType, kind);
return updateNestedTypeForConformance(concreteDecl, kind);
// Form the potential archetype.
return updateNestedTypeForConformance(bestType, kind);
}
PotentialArchetype *PotentialArchetype::updateNestedTypeForConformance(
@@ -2363,6 +2370,12 @@ PotentialArchetype *PotentialArchetype::updateNestedTypeForConformance(
if (!assocType && !concreteDecl)
return nullptr;
// FIXME: Silly hack for a bad interface.
if (concreteDecl && isa<AssociatedTypeDecl>(concreteDecl)) {
assocType = cast<AssociatedTypeDecl>(concreteDecl);
concreteDecl = nullptr;
}
// If we were asked for a complete, well-formed archetype, make sure we
// process delayed requirements if anything changed.
SWIFT_DEFER {