Files
swift-mirror/lib/AST/GenericEnvironment.cpp
Slava Pestov b36f37cc72 Serialization: Preserve identity of opened generic environments
We used to create a new environment for each opened archetype, which is
incorrect when deserializing a nested type of another opened archetype.
2022-08-15 13:59:12 -04:00

497 lines
17 KiB
C++

//===--- GenericEnvironment.cpp - GenericEnvironment AST ------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements the GenericEnvironment class.
//
//===----------------------------------------------------------------------===//
#include "swift/AST/GenericEnvironment.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/ExistentialLayout.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/Basic/Defer.h"
using namespace swift;
size_t GenericEnvironment::numTrailingObjects(
OverloadToken<OpaqueTypeDecl *>) const {
switch (getKind()) {
case Kind::Primary:
case Kind::OpenedExistential:
return 0;
case Kind::Opaque:
return 1;
}
}
size_t GenericEnvironment::numTrailingObjects(
OverloadToken<SubstitutionMap>) const {
switch (getKind()) {
case Kind::Primary:
case Kind::OpenedExistential:
return 0;
case Kind::Opaque:
return 1;
}
}
size_t GenericEnvironment::numTrailingObjects(
OverloadToken<OpenedGenericEnvironmentData>) const {
switch (getKind()) {
case Kind::Primary:
case Kind::Opaque:
return 0;
case Kind::OpenedExistential:
return 1;
}
}
size_t GenericEnvironment::numTrailingObjects(OverloadToken<Type>) const {
return getGenericParams().size();
}
/// Retrieve the array containing the context types associated with the
/// generic parameters, stored in parallel with the generic parameters of the
/// generic signature.
MutableArrayRef<Type> GenericEnvironment::getContextTypes() {
return MutableArrayRef<Type>(getTrailingObjects<Type>(),
getGenericParams().size());
}
/// Retrieve the array containing the context types associated with the
/// generic parameters, stored in parallel with the generic parameters of the
/// generic signature.
ArrayRef<Type> GenericEnvironment::getContextTypes() const {
return ArrayRef<Type>(getTrailingObjects<Type>(),
getGenericParams().size());
}
TypeArrayView<GenericTypeParamType>
GenericEnvironment::getGenericParams() const {
return getGenericSignature().getGenericParams();
}
OpaqueTypeDecl *GenericEnvironment::getOpaqueTypeDecl() const {
assert(getKind() == Kind::Opaque);
return *getTrailingObjects<OpaqueTypeDecl *>();
}
SubstitutionMap GenericEnvironment::getOpaqueSubstitutions() const {
assert(getKind() == Kind::Opaque);
return *getTrailingObjects<SubstitutionMap>();
}
Type GenericEnvironment::getOpenedExistentialType() const {
assert(getKind() == Kind::OpenedExistential);
return getTrailingObjects<OpenedGenericEnvironmentData>()->existential;
}
UUID GenericEnvironment::getOpenedExistentialUUID() const {
assert(getKind() == Kind::OpenedExistential);
return getTrailingObjects<OpenedGenericEnvironmentData>()->uuid;
}
GenericSignature
GenericEnvironment::getOpenedExistentialParentSignature() const {
assert(getKind() == Kind::OpenedExistential);
return getTrailingObjects<OpenedGenericEnvironmentData>()->parentSig;
}
GenericEnvironment::GenericEnvironment(GenericSignature signature)
: SignatureAndKind(signature, Kind::Primary)
{
// Clear out the memory that holds the context types.
std::uninitialized_fill(getContextTypes().begin(), getContextTypes().end(),
Type());
}
GenericEnvironment::GenericEnvironment(
GenericSignature signature,
Type existential, GenericSignature parentSig, UUID uuid)
: SignatureAndKind(signature, Kind::OpenedExistential)
{
new (getTrailingObjects<OpenedGenericEnvironmentData>())
OpenedGenericEnvironmentData{ existential, parentSig, uuid };
// Clear out the memory that holds the context types.
std::uninitialized_fill(getContextTypes().begin(), getContextTypes().end(),
Type());
}
GenericEnvironment::GenericEnvironment(
GenericSignature signature, OpaqueTypeDecl *opaque, SubstitutionMap subs)
: SignatureAndKind(signature, Kind::Opaque)
{
*getTrailingObjects<OpaqueTypeDecl *>() = opaque;
new (getTrailingObjects<SubstitutionMap>()) SubstitutionMap(subs);
// Clear out the memory that holds the context types.
std::uninitialized_fill(getContextTypes().begin(), getContextTypes().end(),
Type());
}
void GenericEnvironment::addMapping(GenericParamKey key,
Type contextType) {
// Find the index into the parallel arrays of generic parameters and
// context types.
auto genericParams = getGenericParams();
unsigned index = key.findIndexIn(genericParams);
assert(genericParams[index] == key && "Bad generic parameter");
// Add the mapping from the generic parameter to the context type.
assert(getContextTypes()[index].isNull() ||
getContextTypes()[index]->is<ErrorType>() &&
"Already recoded this mapping");
getContextTypes()[index] = contextType;
}
Optional<Type> GenericEnvironment::getMappingIfPresent(
GenericParamKey key) const {
// Find the index into the parallel arrays of generic parameters and
// context types.
auto genericParams = getGenericParams();
unsigned index = key.findIndexIn(genericParams);
assert(genericParams[index] == key && "Bad generic parameter");
if (auto type = getContextTypes()[index])
return type;
return None;
}
namespace {
/// Substitute the outer generic parameters from a substitution map, ignoring
/// innter generic parameters with a given depth.
struct SubstituteOuterFromSubstitutionMap {
SubstitutionMap subs;
unsigned depth;
/// Whether this is a type parameter that should not be substituted.
bool isUnsubstitutedTypeParameter(Type type) const {
if (!type->isTypeParameter())
return false;
if (auto depMemTy = type->getAs<DependentMemberType>())
return isUnsubstitutedTypeParameter(depMemTy->getBase());
if (auto genericParam = type->getAs<GenericTypeParamType>())
return genericParam->getDepth() >= depth;
return false;
}
Type operator()(SubstitutableType *type) const {
if (isUnsubstitutedTypeParameter(type))
return Type(type);
return QuerySubstitutionMap{subs}(type);
}
ProtocolConformanceRef operator()(CanType dependentType,
Type conformingReplacementType,
ProtocolDecl *conformedProtocol) const {
if (isUnsubstitutedTypeParameter(dependentType))
return ProtocolConformanceRef(conformedProtocol);
return LookUpConformanceInSubstitutionMap(subs)(
dependentType, conformingReplacementType, conformedProtocol);
}
};
}
Type GenericEnvironment::maybeApplyOpaqueTypeSubstitutions(Type type) const {
switch (getKind()) {
case Kind::Primary:
case Kind::OpenedExistential:
return type;
case Kind::Opaque: {
// Substitute outer generic parameters of an opaque archetype environment.
unsigned opaqueDepth =
getOpaqueTypeDecl()->getOpaqueGenericParams().front()->getDepth();
SubstituteOuterFromSubstitutionMap replacer{
getOpaqueSubstitutions(), opaqueDepth};
return type.subst(replacer, replacer);
}
}
}
Type GenericEnvironment::mapTypeIntoContext(GenericEnvironment *env,
Type type) {
assert((!type->hasArchetype() || type->hasOpenedExistential()) &&
"already have a contextual type");
assert((env || !type->hasTypeParameter()) &&
"no generic environment provided for type with type parameters");
if (!env) {
return type;
}
return env->mapTypeIntoContext(type);
}
Type MapTypeOutOfContext::operator()(SubstitutableType *type) const {
auto archetype = cast<ArchetypeType>(type);
if (isa<OpaqueTypeArchetypeType>(archetype->getRoot()))
return Type();
// Leave opened archetypes alone; they're handled contextually.
if (isa<OpenedArchetypeType>(archetype))
return Type(type);
return archetype->getInterfaceType();
}
Type TypeBase::mapTypeOutOfContext() {
assert(!hasTypeParameter() && "already have an interface type");
return Type(this).subst(MapTypeOutOfContext(),
MakeAbstractConformanceForGenericType(),
SubstFlags::AllowLoweredTypes);
}
class GenericEnvironment::NestedTypeStorage
: public llvm::DenseMap<CanType, Type> { };
auto GenericEnvironment::getOrCreateNestedTypeStorage() -> NestedTypeStorage & {
if (nestedTypeStorage)
return *nestedTypeStorage;
nestedTypeStorage = new NestedTypeStorage();
ASTContext &ctx = getGenericParams().front()->getASTContext();
ctx.addCleanup([nestedTypeStorage=this->nestedTypeStorage]() {
delete nestedTypeStorage;
});
return *nestedTypeStorage;
}
Type
GenericEnvironment::getOrCreateArchetypeFromInterfaceType(Type depType) {
auto genericSig = getGenericSignature();
LookUpConformanceInSignature conformanceLookupFn(genericSig.getPointer());
auto requirements = genericSig->getLocalRequirements(depType);
/// Substitute a type for the purpose of requirements.
auto substForRequirements = [&](Type type) {
switch (getKind()) {
case Kind::Primary:
case Kind::OpenedExistential:
if (type->hasTypeParameter()) {
return mapTypeIntoContext(type, conformanceLookupFn);
} else {
return type;
}
case Kind::Opaque:
return maybeApplyOpaqueTypeSubstitutions(type);
}
};
if (requirements.concreteType) {
return substForRequirements(requirements.concreteType);
}
assert(requirements.anchor && "No anchor or concrete type?");
auto &ctx = genericSig->getASTContext();
// First, write an ErrorType to the location where this type is cached,
// to catch re-entrant lookups that might arise from an invalid generic
// signature (eg, <X where X == Array<X>>).
CanDependentMemberType nestedType;
GenericTypeParamType *genericParam = nullptr;
if (auto depMemTy = requirements.anchor->getAs<DependentMemberType>()) {
nestedType = cast<DependentMemberType>(depMemTy->getCanonicalType());
auto &entry = getOrCreateNestedTypeStorage()[nestedType];
if (entry)
return entry;
entry = ErrorType::get(ctx);
} else {
genericParam = requirements.anchor->castTo<GenericTypeParamType>();
if (auto type = getMappingIfPresent(genericParam))
return *type;
addMapping(genericParam, ErrorType::get(ctx));
}
// Substitute into the superclass.
Type superclass = requirements.superclass;
if (superclass && superclass->hasTypeParameter()) {
superclass = substForRequirements(superclass);
if (superclass->is<ErrorType>())
superclass = Type();
}
Type result;
auto rootGP = requirements.anchor->getRootGenericParam();
if (rootGP->isTypeSequence()) {
assert(getKind() == Kind::Primary);
result = SequenceArchetypeType::get(ctx, this, requirements.anchor,
requirements.protos, superclass,
requirements.layout);
} else {
switch (getKind()) {
case Kind::Primary:
result = PrimaryArchetypeType::getNew(ctx, this, requirements.anchor,
requirements.protos, superclass,
requirements.layout);
break;
case Kind::OpenedExistential: {
// FIXME: The existential layout's protocols might differ from the
// canonicalized set of protocols determined by the generic signature.
// Before NestedArchetypeType was removed, we used the former when
// building a root OpenedArchetypeType, and the latter when building
// nested archetypes.
// For compatibility, continue using the existential layout's version when
// the interface type is a generic parameter. We should align these at
// some point.
if (depType->is<GenericTypeParamType>()) {
auto layout = getOpenedExistentialType()->getExistentialLayout();
SmallVector<ProtocolDecl *, 2> protos;
for (auto proto : layout.getProtocols())
protos.push_back(proto);
result = OpenedArchetypeType::getNew(this, requirements.anchor, protos,
superclass, requirements.layout);
} else {
result = OpenedArchetypeType::getNew(this, requirements.anchor,
requirements.protos, superclass,
requirements.layout);
}
break;
}
case Kind::Opaque: {
// If the anchor type isn't rooted in a generic parameter that
// represents an opaque declaration, then apply the outer substitutions.
// It would be incorrect to build an opaque type archetype here.
unsigned opaqueDepth =
getOpaqueTypeDecl()->getOpaqueGenericParams().front()->getDepth();
if (rootGP->getDepth() < opaqueDepth) {
result = maybeApplyOpaqueTypeSubstitutions(requirements.anchor);
break;
}
result = OpaqueTypeArchetypeType::getNew(this, requirements.anchor,
requirements.protos, superclass,
requirements.layout);
break;
}
}
}
if (genericParam)
addMapping(genericParam, result);
else
getOrCreateNestedTypeStorage()[nestedType] = result;
return result;
}
Type QueryInterfaceTypeSubstitutions::operator()(SubstitutableType *type) const{
if (auto gp = type->getAs<GenericTypeParamType>()) {
// Find the index into the parallel arrays of generic parameters and
// context types.
auto genericParams = self->getGenericParams();
GenericParamKey key(gp);
// Make sure that this generic parameter is from this environment.
unsigned index = key.findIndexIn(genericParams);
if (index == genericParams.size() || genericParams[index] != key)
return Type();
// If the context type isn't already known, lazily create it.
auto mutableSelf = const_cast<GenericEnvironment *>(self);
Type &contextType = mutableSelf->getContextTypes()[index];
if (contextType)
return contextType;
auto result = mutableSelf->getOrCreateArchetypeFromInterfaceType(type);
assert (!contextType ||
contextType->isEqual(result) ||
contextType->is<ErrorType>());
contextType = result;
return result;
}
return Type();
}
Type GenericEnvironment::mapTypeIntoContext(
Type type,
LookupConformanceFn lookupConformance) const {
assert((!type->hasArchetype() || type->hasOpenedExistential()) &&
"already have a contextual type");
type = maybeApplyOpaqueTypeSubstitutions(type);
Type result = type.subst(QueryInterfaceTypeSubstitutions(this),
lookupConformance,
SubstFlags::AllowLoweredTypes);
assert((!result->hasTypeParameter() || result->hasError() ||
getKind() == Kind::Opaque) &&
"not fully substituted");
return result;
}
Type GenericEnvironment::mapTypeIntoContext(Type type) const {
auto sig = getGenericSignature();
return mapTypeIntoContext(type, LookUpConformanceInSignature(sig.getPointer()));
}
Type GenericEnvironment::mapTypeIntoContext(GenericTypeParamType *type) const {
auto self = const_cast<GenericEnvironment *>(this);
Type result = QueryInterfaceTypeSubstitutions(self)(type);
if (!result)
return ErrorType::get(type);
return result;
}
SubstitutionMap GenericEnvironment::getForwardingSubstitutionMap() const {
auto genericSig = getGenericSignature();
return SubstitutionMap::get(genericSig,
QueryInterfaceTypeSubstitutions(this),
MakeAbstractConformanceForGenericType());
}
std::pair<Type, ProtocolConformanceRef>
GenericEnvironment::mapConformanceRefIntoContext(GenericEnvironment *genericEnv,
Type conformingType,
ProtocolConformanceRef conformance) {
if (!genericEnv)
return {conformingType, conformance};
return genericEnv->mapConformanceRefIntoContext(conformingType, conformance);
}
std::pair<Type, ProtocolConformanceRef>
GenericEnvironment::mapConformanceRefIntoContext(
Type conformingInterfaceType,
ProtocolConformanceRef conformance) const {
auto contextConformance = conformance.subst(conformingInterfaceType,
QueryInterfaceTypeSubstitutions(this),
LookUpConformanceInSignature(getGenericSignature().getPointer()));
auto contextType = mapTypeIntoContext(conformingInterfaceType);
return {contextType, contextConformance};
}