mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
0184d9719b
We now have this information during parsing and throw it away during deserialization. This half-baked state works because all non-generic-extension clients only care about the module context. Swift SVN r20833
449 lines
18 KiB
C++
449 lines
18 KiB
C++
//===--- ProtocolConformance.cpp - AST Protocol Conformance -----*- C++ -*-===//
|
|
//
|
|
// This source file is part of the Swift.org open source project
|
|
//
|
|
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
|
|
// Licensed under Apache License v2.0 with Runtime Library Exception
|
|
//
|
|
// See http://swift.org/LICENSE.txt for license information
|
|
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the protocol conformance data structures.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
#include "swift/Basic/Fallthrough.h"
|
|
#include "swift/AST/ASTContext.h"
|
|
#include "swift/AST/ProtocolConformance.h"
|
|
#include "swift/AST/Decl.h"
|
|
#include "swift/AST/LazyResolver.h"
|
|
#include "swift/AST/Module.h"
|
|
#include "swift/AST/Substitution.h"
|
|
#include "swift/AST/Types.h"
|
|
#include "swift/AST/TypeWalker.h"
|
|
|
|
using namespace swift;
|
|
|
|
void *ProtocolConformance::operator new(size_t bytes, ASTContext &context,
|
|
AllocationArena arena,
|
|
unsigned alignment) {
|
|
return context.Allocate(bytes, alignment, arena);
|
|
|
|
}
|
|
|
|
#define CONFORMANCE_SUBCLASS_DISPATCH(Method, Args) \
|
|
switch (getKind()) { \
|
|
case ProtocolConformanceKind::Normal: \
|
|
static_assert(&ProtocolConformance::Method != \
|
|
&NormalProtocolConformance::Method, \
|
|
"Must override NormalProtocolConformance::" #Method); \
|
|
return cast<NormalProtocolConformance>(this)->Method Args; \
|
|
case ProtocolConformanceKind::Specialized: \
|
|
static_assert(&ProtocolConformance::Method != \
|
|
&SpecializedProtocolConformance::Method, \
|
|
"Must override SpecializedProtocolConformance::" #Method); \
|
|
return cast<SpecializedProtocolConformance>(this)->Method Args; \
|
|
case ProtocolConformanceKind::Inherited: \
|
|
static_assert(&ProtocolConformance::Method != \
|
|
&InheritedProtocolConformance::Method, \
|
|
"Must override InheritedProtocolConformance::" #Method); \
|
|
return cast<InheritedProtocolConformance>(this)->Method Args; \
|
|
}
|
|
|
|
/// Get the protocol being conformed to.
|
|
ProtocolDecl *ProtocolConformance::getProtocol() const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(getProtocol, ())
|
|
}
|
|
|
|
DeclContext *ProtocolConformance::getDeclContext() const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(getDeclContext, ())
|
|
}
|
|
|
|
/// Retrieve the state of this conformance.
|
|
ProtocolConformanceState ProtocolConformance::getState() const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(getState, ())
|
|
}
|
|
|
|
const Substitution &
|
|
ProtocolConformance::getTypeWitness(AssociatedTypeDecl *assocType,
|
|
LazyResolver *resolver) const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(getTypeWitness, (assocType, resolver))
|
|
}
|
|
|
|
ConcreteDeclRef ProtocolConformance::getWitness(ValueDecl *requirement,
|
|
LazyResolver *resolver) const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(getWitness, (requirement, resolver))
|
|
}
|
|
|
|
const InheritedConformanceMap &
|
|
ProtocolConformance::getInheritedConformances() const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(getInheritedConformances, ())
|
|
}
|
|
|
|
/// Determine whether the witness for the given requirement
|
|
/// is either the default definition or was otherwise deduced.
|
|
bool ProtocolConformance::usesDefaultDefinition(ValueDecl *requirement) const {
|
|
CONFORMANCE_SUBCLASS_DISPATCH(usesDefaultDefinition, (requirement))
|
|
}
|
|
|
|
/// FIXME: This should be an independent property of the conformance.
|
|
/// Assuming a BoundGenericType conformance is always for the
|
|
/// DeclaredTypeInContext is unsound if we ever add constrained extensions.
|
|
static GenericParamList *genericParamListForType(Type ty) {
|
|
while (ty) {
|
|
if (auto nt = ty->getAs<NominalType>())
|
|
ty = nt->getParent();
|
|
else
|
|
break;
|
|
}
|
|
|
|
if (!ty)
|
|
return nullptr;
|
|
|
|
if (auto bgt = ty->getAs<BoundGenericType>()) {
|
|
auto decl = bgt->getDecl();
|
|
assert(bgt->isEqual(decl->getDeclaredTypeInContext()) &&
|
|
"conformance for constrained generic type not implemented");
|
|
return decl->getGenericParams();
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
/// Return the list of generic params that were substituted if this conformance
|
|
/// was specialized somewhere along the inheritence chain.
|
|
GenericParamList *ProtocolConformance::getSubstitutedGenericParams() const {
|
|
const ProtocolConformance *C = this;
|
|
|
|
bool FoundSpecializedConformance = false;
|
|
while (true) {
|
|
switch (C->getKind()) {
|
|
case ProtocolConformanceKind::Inherited:
|
|
// If we have an inherited protocol conformance, grab our inherited
|
|
// conformance and continue. Inheritence in it of itself does not yield
|
|
// additional type variables.
|
|
C = cast<InheritedProtocolConformance>(C)->getInheritedConformance();
|
|
continue;
|
|
case ProtocolConformanceKind::Specialized:
|
|
// If we have a specialized protocol conformance, since we do not support
|
|
// currently partial specialization, we know that it can not have any open
|
|
// type variables.
|
|
C = cast<SpecializedProtocolConformance>(C)->getGenericConformance();
|
|
FoundSpecializedConformance = true;
|
|
continue;
|
|
case ProtocolConformanceKind::Normal: {
|
|
// If we have a normal protocol conformance and we have not seen a
|
|
// specialized protocol conformance yet, we know that the normal protocol
|
|
// conformance can only contain open types. Bail.
|
|
if (!FoundSpecializedConformance)
|
|
return nullptr;
|
|
|
|
|
|
// Otherwise, this must be the original conformance containing the
|
|
// specialized generic parameters. Attempt to create the param list.
|
|
auto normal = cast<NormalProtocolConformance>(C);
|
|
if (auto ext = dyn_cast<ExtensionDecl>(normal->getDeclContext()))
|
|
return ext->getGenericParams();
|
|
|
|
return genericParamListForType(C->getType());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
GenericParamList *ProtocolConformance::getGenericParams() const {
|
|
const ProtocolConformance *C = this;
|
|
|
|
while (true) {
|
|
switch (C->getKind()) {
|
|
case ProtocolConformanceKind::Inherited:
|
|
// If we have an inherited protocol conformance, grab our inherited
|
|
// conformance and continue.
|
|
C = cast<InheritedProtocolConformance>(C)->getInheritedConformance();
|
|
continue;
|
|
case ProtocolConformanceKind::Specialized:
|
|
// If we have a specialized protocol conformance, since we do not support
|
|
// currently partial specialization, we know that it can not have any open
|
|
// type variables.
|
|
return nullptr;
|
|
case ProtocolConformanceKind::Normal: {
|
|
// If we have a normal protocol conformance, attempt to look up its open
|
|
// generic type variables.
|
|
auto normal = cast<NormalProtocolConformance>(C);
|
|
if (auto ext = dyn_cast<ExtensionDecl>(normal->getDeclContext()))
|
|
return ext->getGenericParams();
|
|
|
|
return genericParamListForType(C->getType());
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
Type ProtocolConformance::getInterfaceType() const {
|
|
switch (getKind()) {
|
|
case ProtocolConformanceKind::Normal:
|
|
// FIXME: This should be the type stored in the protocol conformance.
|
|
// Assuming a generic conformance is always for the DeclaredTypeInContext
|
|
// is unsound if we ever add constrained extensions.
|
|
return getType()->getNominalOrBoundGenericNominal()
|
|
->getDeclaredInterfaceType();
|
|
|
|
case ProtocolConformanceKind::Inherited:
|
|
return cast<InheritedProtocolConformance>(this)->getInheritedConformance()
|
|
->getInterfaceType();
|
|
|
|
case ProtocolConformanceKind::Specialized:
|
|
// Assume a specialized conformance is fully applied.
|
|
return getType();
|
|
}
|
|
}
|
|
|
|
GenericSignature *ProtocolConformance::getGenericSignature() const {
|
|
// FIXME: Should be an independent property of the conformance.
|
|
// Assuming a BoundGenericType conformance is always for the
|
|
// DeclaredTypeInContext is unsound if we ever add constrained extensions.
|
|
|
|
return getType()->getNominalOrBoundGenericNominal()
|
|
->getGenericSignatureOfContext();
|
|
}
|
|
|
|
const Substitution &NormalProtocolConformance::getTypeWitness(
|
|
AssociatedTypeDecl *assocType,
|
|
LazyResolver *resolver) const {
|
|
auto known = TypeWitnesses.find(assocType);
|
|
if (known == TypeWitnesses.end()) {
|
|
assert(resolver && "Unable to resolve type witness");
|
|
resolver->resolveTypeWitness(this, assocType);
|
|
known = TypeWitnesses.find(assocType);
|
|
assert(known != TypeWitnesses.end() && "Didn't resolve witness?");
|
|
}
|
|
|
|
return known->second;
|
|
}
|
|
|
|
void NormalProtocolConformance::setTypeWitness(
|
|
AssociatedTypeDecl *assocType,
|
|
const Substitution &substitution) const {
|
|
assert(getProtocol() == cast<ProtocolDecl>(assocType->getDeclContext()) &&
|
|
"associated type in wrong protocol");
|
|
assert(TypeWitnesses.count(assocType) == 0 && "Type witness already known");
|
|
assert(!isComplete() && "Conformance already complete?");
|
|
TypeWitnesses[assocType] = substitution;
|
|
}
|
|
|
|
/// Retrieve the value witness corresponding to the given requirement.
|
|
ConcreteDeclRef NormalProtocolConformance::getWitness(
|
|
ValueDecl *requirement,
|
|
LazyResolver *resolver) const {
|
|
assert(!isa<AssociatedTypeDecl>(requirement) && "Request type witness");
|
|
auto known = Mapping.find(requirement);
|
|
if (known == Mapping.end()) {
|
|
assert(resolver && "Unable to resolve witness without resolver");
|
|
resolver->resolveWitness(this, requirement);
|
|
known = Mapping.find(requirement);
|
|
assert(known != Mapping.end() && "Resolver did not resolve requirement");
|
|
}
|
|
|
|
return known->second;
|
|
}
|
|
|
|
void NormalProtocolConformance::setWitness(ValueDecl *requirement,
|
|
ConcreteDeclRef witness) const {
|
|
assert(!isa<AssociatedTypeDecl>(requirement) && "Request type witness");
|
|
assert(getProtocol() == cast<ProtocolDecl>(requirement->getDeclContext()) &&
|
|
"requirement in wrong protocol");
|
|
assert(Mapping.count(requirement) == 0 && "Witness already known");
|
|
assert(!isComplete() && "Conformance already complete?");
|
|
Mapping[requirement] = witness;
|
|
}
|
|
|
|
SpecializedProtocolConformance::SpecializedProtocolConformance(
|
|
Type conformingType,
|
|
ProtocolConformance *genericConformance,
|
|
ArrayRef<Substitution> substitutions)
|
|
: ProtocolConformance(ProtocolConformanceKind::Specialized, conformingType),
|
|
GenericConformance(genericConformance),
|
|
GenericSubstitutions(substitutions)
|
|
{
|
|
assert(genericConformance->getKind() != ProtocolConformanceKind::Specialized);
|
|
}
|
|
|
|
const Substitution &SpecializedProtocolConformance::getTypeWitness(
|
|
AssociatedTypeDecl *assocType,
|
|
LazyResolver *resolver) const {
|
|
// If we've already created this type witness, return it.
|
|
auto known = TypeWitnesses.find(assocType);
|
|
if (known != TypeWitnesses.end()) {
|
|
return known->second;
|
|
}
|
|
|
|
// Otherwise, perform substitutions to create this witness now.
|
|
TypeSubstitutionMap substitutionMap = GenericConformance->getGenericParams()
|
|
->getSubstitutionMap(GenericSubstitutions);
|
|
|
|
auto &genericWitness
|
|
= GenericConformance->getTypeWitness(assocType, resolver);
|
|
auto conformingDC = getDeclContext();
|
|
auto conformingModule = conformingDC->getParentModule();
|
|
auto specializedType
|
|
= genericWitness.getReplacement().subst(conformingModule,
|
|
substitutionMap,
|
|
/*ignoreMissing=*/false,
|
|
resolver);
|
|
|
|
// If the type witness was unchanged, just copy it directly.
|
|
if (specializedType.getPointer() == genericWitness.getReplacement().getPointer()) {
|
|
TypeWitnesses[assocType] = genericWitness;
|
|
return TypeWitnesses[assocType];
|
|
}
|
|
|
|
// Gather the conformances for the type witness. These should never fail.
|
|
SmallVector<ProtocolConformance *, 4> conformances;
|
|
auto archetype = genericWitness.getArchetype();
|
|
for (auto proto : archetype->getConformsTo()) {
|
|
auto conforms = conformingModule->lookupConformance(specializedType, proto,
|
|
resolver);
|
|
assert((conforms.getInt() == ConformanceKind::Conforms ||
|
|
specializedType->is<TypeVariableType>() ||
|
|
specializedType->is<DependentMemberType>()) &&
|
|
"Improperly checked substitution");
|
|
conformances.push_back(conforms.getPointer());
|
|
}
|
|
|
|
// Form the substitution.
|
|
auto &ctx = assocType->getASTContext();
|
|
TypeWitnesses[assocType] = Substitution{archetype, specializedType,
|
|
ctx.AllocateCopy(conformances)};
|
|
return TypeWitnesses[assocType];
|
|
}
|
|
|
|
ConcreteDeclRef
|
|
SpecializedProtocolConformance::getWitness(ValueDecl *requirement,
|
|
LazyResolver *resolver) const {
|
|
// FIXME: Apply substitutions here!
|
|
return GenericConformance->getWitness(requirement, resolver);
|
|
}
|
|
|
|
const NormalProtocolConformance *
|
|
ProtocolConformance::getRootNormalConformance() const {
|
|
const ProtocolConformance *C = this;
|
|
while (!isa<NormalProtocolConformance>(C)) {
|
|
switch (C->getKind()) {
|
|
case ProtocolConformanceKind::Normal:
|
|
llvm_unreachable("should have broken out of loop");
|
|
case ProtocolConformanceKind::Inherited:
|
|
C = cast<InheritedProtocolConformance>(C)
|
|
->getInheritedConformance();
|
|
break;
|
|
case ProtocolConformanceKind::Specialized:
|
|
C = cast<SpecializedProtocolConformance>(C)
|
|
->getGenericConformance();
|
|
break;
|
|
}
|
|
}
|
|
return cast<NormalProtocolConformance>(C);
|
|
}
|
|
|
|
ProtocolConformance *ProtocolConformance::subst(Module *module,
|
|
Type substType,
|
|
ArrayRef<Substitution> subs,
|
|
TypeSubstitutionMap &subMap,
|
|
ArchetypeConformanceMap &conformanceMap) {
|
|
if (getType()->isEqual(substType))
|
|
return this;
|
|
|
|
switch (getKind()) {
|
|
case ProtocolConformanceKind::Normal:
|
|
if (substType->isSpecialized()) {
|
|
assert(getType()->isSpecialized()
|
|
&& "substitution mapped non-specialized to specialized?!");
|
|
assert(getType()->getNominalOrBoundGenericNominal()
|
|
== substType->getNominalOrBoundGenericNominal()
|
|
&& "substitution mapped to different nominal?!");
|
|
return module->getASTContext()
|
|
.getSpecializedConformance(substType, this,
|
|
substType->gatherAllSubstitutions(module, nullptr));
|
|
}
|
|
assert(substType->isEqual(getType())
|
|
&& "substitution changed non-specialized type?!");
|
|
return this;
|
|
|
|
case ProtocolConformanceKind::Inherited: {
|
|
// Substitute the base.
|
|
ProtocolConformance *newBase
|
|
= cast<InheritedProtocolConformance>(this)->getInheritedConformance()
|
|
->subst(module, substType, subs, subMap, conformanceMap);
|
|
return module->getASTContext()
|
|
.getInheritedConformance(substType, newBase);
|
|
}
|
|
case ProtocolConformanceKind::Specialized: {
|
|
// Substitute the substitutions in the specialized conformance.
|
|
auto spec = cast<SpecializedProtocolConformance>(this);
|
|
SmallVector<Substitution, 8> newSubs;
|
|
newSubs.reserve(spec->getGenericSubstitutions().size());
|
|
for (auto &sub : spec->getGenericSubstitutions())
|
|
newSubs.push_back(sub.subst(module, subs, subMap, conformanceMap));
|
|
|
|
auto ctxNewSubs = module->getASTContext().AllocateCopy(newSubs);
|
|
|
|
return module->getASTContext()
|
|
.getSpecializedConformance(substType, spec->getGenericConformance(),
|
|
ctxNewSubs);
|
|
}
|
|
}
|
|
}
|
|
|
|
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;
|
|
ArrayRef<Substitution> subs;
|
|
switch (getKind()) {
|
|
case ProtocolConformanceKind::Specialized: {
|
|
auto spec = cast<SpecializedProtocolConformance>(this);
|
|
unspecialized = spec->getGenericConformance();
|
|
subs = spec->getGenericSubstitutions();
|
|
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()) {
|
|
return getType()->getASTContext()
|
|
.getSpecializedConformance(getType(), foundInherited, subs);
|
|
}
|
|
assert(getType()->isEqual(foundInherited->getType())
|
|
&& "inherited conformance does not match type");
|
|
return foundInherited;
|
|
}
|