static DynamicCastFeasibility
classifyDynamicCastFromProtocol(ModuleDecl *M, CanType source, CanType target,
bool isWholeModuleOpts) {
assert(source.isExistentialType() &&
"source should be an existential type");
if (source == target)
return DynamicCastFeasibility::WillSucceed;
// Casts from class existential into a non-class can never succeed.
if (source->isClassExistentialType() &&
!target.isAnyExistentialType() &&
!target.getClassOrBoundGenericClass() &&
!isa<ArchetypeType>(target) &&
!mayBridgeToObjectiveC(M, target)) {
assert((target.getEnumOrBoundGenericEnum() ||
target.getStructOrBoundGenericStruct() ||
isa<TupleType>(target) ||
isa<SILFunctionType>(target) ||
isa<FunctionType>(target) ||
isa<MetatypeType>(target)) &&
"Target should be an enum, struct, tuple, metatype or function type");
return DynamicCastFeasibility::WillFail;
}
// TODO: maybe prove that certain conformances are impossible?
return DynamicCastFeasibility::MaySucceed;
}
/// Build an interface type substitution map for the given generic signature
/// from a type substitution function and conformance lookup function.
SubstitutionMap SubstitutionMap::get(GenericSignature *genericSig,
TypeSubstitutionFn subs,
LookupConformanceFn lookupConformance) {
if (!genericSig) {
return SubstitutionMap();
}
// Form the replacement types.
SmallVector<Type, 4> replacementTypes;
replacementTypes.reserve(genericSig->getGenericParams().size());
for (auto gp : genericSig->getGenericParams()) {
// Don't eagerly form replacements for non-canonical generic parameters.
if (!genericSig->isCanonicalTypeInContext(gp->getCanonicalType())) {
replacementTypes.push_back(Type());
continue;
}
// Record the replacement.
Type replacement = Type(gp).subst(subs, lookupConformance,
SubstFlags::UseErrorType);
replacementTypes.push_back(replacement);
}
// Form the stored conformances.
SmallVector<ProtocolConformanceRef, 4> conformances;
for (const auto &req : genericSig->getRequirements()) {
if (req.getKind() != RequirementKind::Conformance) continue;
CanType depTy = req.getFirstType()->getCanonicalType();
auto replacement = depTy.subst(subs, lookupConformance,
SubstFlags::UseErrorType);
auto protoType = req.getSecondType()->castTo<ProtocolType>();
auto proto = protoType->getDecl();
auto conformance = lookupConformance(depTy, replacement, proto)
.getValueOr(ProtocolConformanceRef(proto));
conformances.push_back(conformance);
}
return SubstitutionMap(genericSig, replacementTypes, conformances);
}
// Collect any builtin types referenced from this type.
void addBuiltinTypeRefs(CanType type) {
type.visit([&](Type t) {
if (t->is<BuiltinType>())
BuiltinTypes.insert(CanType(t));
// We need at least size/alignment information for types imported by
// clang, so we'll treat them as a builtin type, essentially an
// opaque blob.
if (auto Nominal = t->getAnyNominal())
if (Nominal->hasClangNode())
BuiltinTypes.insert(CanType(t));
});
}
/// Perform a foreign error check by testing whether the call result is zero.
/// The call result is otherwise ignored.
static void
emitResultIsZeroErrorCheck(SILGenFunction &gen, SILLocation loc,
ManagedValue result, ManagedValue errorSlot,
bool suppressErrorCheck, bool zeroIsError) {
// Just ignore the call result if we're suppressing the error check.
if (suppressErrorCheck) {
return;
}
SILValue resultValue =
emitUnwrapIntegerResult(gen, loc, result.getUnmanagedValue());
CanType resultType = resultValue->getType().getSwiftRValueType();
if (!resultType->isBuiltinIntegerType(1)) {
SILValue zero =
gen.B.createIntegerLiteral(loc, resultValue->getType(), 0);
ASTContext &ctx = gen.getASTContext();
resultValue =
gen.B.createBuiltinBinaryFunction(loc,
"cmp_ne",
resultValue->getType(),
SILType::getBuiltinIntegerType(1, ctx),
{resultValue, zero});
}
SILBasicBlock *errorBB = gen.createBasicBlock(FunctionSection::Postmatter);
SILBasicBlock *contBB = gen.createBasicBlock();
if (zeroIsError)
gen.B.createCondBranch(loc, resultValue, contBB, errorBB);
else
gen.B.createCondBranch(loc, resultValue, errorBB, contBB);
gen.emitForeignErrorBlock(loc, errorBB, errorSlot);
gen.B.emitBlock(contBB);
}
FormalLinkage swift::getTypeLinkage(CanType type) {
FormalLinkage result = FormalLinkage::Top;
// Merge all nominal types from the structural type.
(void) type.findIf([&](Type _type) {
CanType type = CanType(_type);
// For any nominal type reference, look at the type declaration.
if (auto nominal = type->getAnyNominal()) {
result ^= getDeclLinkage(nominal);
// For polymorphic function types, look at the generic parameters.
// FIXME: findIf should do this, once polymorphic function types can be
// canonicalized and re-formed properly.
} else if (auto polyFn = dyn_cast<PolymorphicFunctionType>(type)) {
result ^= getGenericClauseLinkage(polyFn->getGenericParameters());
}
return false; // continue searching
});
return result;
}
/// Return a value for an optional ".Some(x)" of the specified type. This only
/// works for loadable enum types.
ManagedValue SILGenFunction::
getOptionalSomeValue(SILLocation loc, ManagedValue value,
const TypeLowering &optTL) {
assert(optTL.isLoadable() && "Address-only optionals cannot use this");
SILType optType = optTL.getLoweredType();
CanType formalOptType = optType.getSwiftRValueType();
OptionalTypeKind OTK;
auto formalObjectType = formalOptType->getAnyOptionalObjectType(OTK)
->getCanonicalType();
assert(OTK != OTK_None);
auto someDecl = getASTContext().getOptionalSomeDecl(OTK);
AbstractionPattern origType = AbstractionPattern::getOpaque();
// Reabstract input value to the type expected by the enum.
value = emitSubstToOrigValue(loc, value, origType, formalObjectType);
SILValue result =
B.createEnum(loc, value.forward(*this), someDecl,
optTL.getLoweredType());
return emitManagedRValueWithCleanup(result, optTL);
}
bool DestructorAnalysis::isSafeType(CanType Ty) {
// Don't visit types twice.
auto CachedRes = Cached.find(Ty);
if (CachedRes != Cached.end()) {
return CachedRes->second;
}
// Before we recurse mark the type as safe i.e if we see it in a recursive
// position it is safe in the absence of another fact that proves otherwise.
// We will reset this value to the correct value once we return from the
// recursion below.
cacheResult(Ty, true);
// Trivial value types.
if (Ty->is<BuiltinIntegerType>())
return cacheResult(Ty, true);
if (Ty->is<BuiltinFloatType>())
return cacheResult(Ty, true);
// A struct is safe if
// * either it implements the _DestructorSafeContainer protocol and
// all the type parameters are safe types.
// * or all stored properties are safe types.
if (auto *Struct = Ty->getStructOrBoundGenericStruct()) {
if (implementsDestructorSafeContainerProtocol(Struct) &&
areTypeParametersSafe(Ty))
return cacheResult(Ty, true);
// Check the stored properties.
for (auto SP : Struct->getStoredProperties())
if (!isSafeType(SP->getInterfaceType()->getCanonicalType()))
return cacheResult(Ty, false);
return cacheResult(Ty, true);
}
// A tuple type is safe if its elements are safe.
if (auto Tuple = dyn_cast<TupleType>(Ty)) {
for (auto &Elt : Tuple->getElements())
if (!isSafeType(Elt.getType()->getCanonicalType()))
return cacheResult(Ty, false);
return cacheResult(Ty, true);
}
// TODO: enum types.
return cacheResult(Ty, false);
}
CanType swift::getNSBridgedClassOfCFClass(ModuleDecl *M, CanType type) {
if (auto classDecl = type->getClassOrBoundGenericClass()) {
if (classDecl->getForeignClassKind() == ClassDecl::ForeignKind::CFType) {
if (auto bridgedAttr =
classDecl->getAttrs().getAttribute<ObjCBridgedAttr>()) {
auto bridgedClass = bridgedAttr->getObjCClass();
// TODO: this should handle generic classes properly.
if (!bridgedClass->isGenericContext()) {
return bridgedClass->getDeclaredInterfaceType()->getCanonicalType();
}
}
}
}
return CanType();
}
/// Add a 32-bit relative offset to a mangled typeref string
/// in the typeref reflection section.
void addTypeRef(Module *ModuleContext, CanType type) {
assert(type);
// Generic parameters should be written in terms of interface types
// for the purposes of reflection metadata
assert(!type->hasArchetype() && "Forgot to map typeref out of context");
Mangle::Mangler mangler(/*DWARFMangling*/false,
/*usePunyCode*/ true,
/*OptimizeProtocolNames*/ false);
mangler.setModuleContext(ModuleContext);
mangler.mangleType(type, 0);
auto mangledName = IGM.getAddrOfStringForTypeRef(mangler.finalize());
addRelativeAddress(mangledName);
}
CanType TypeConverter::getBridgedInputType(SILFunctionTypeRepresentation rep,
AbstractionPattern pattern,
CanType input) {
if (auto tuple = dyn_cast<TupleType>(input)) {
SmallVector<TupleTypeElt, 4> bridgedFields;
bool changed = false;
for (unsigned i : indices(tuple->getElements())) {
auto &elt = tuple->getElement(i);
Type bridged = getLoweredBridgedType(pattern.getTupleElementType(i),
elt.getType(), rep,
TypeConverter::ForArgument);
if (!bridged) {
Context.Diags.diagnose(SourceLoc(), diag::could_not_find_bridge_type,
elt.getType());
llvm::report_fatal_error("unable to set up the ObjC bridge!");
}
CanType canBridged = bridged->getCanonicalType();
if (canBridged != CanType(elt.getType())) {
changed = true;
bridgedFields.push_back(elt.getWithType(canBridged));
} else {
bridgedFields.push_back(elt);
}
}
if (!changed)
return input;
return CanType(TupleType::get(bridgedFields, input->getASTContext()));
}
auto loweredBridgedType = getLoweredBridgedType(pattern, input, rep,
TypeConverter::ForArgument);
if (!loweredBridgedType) {
Context.Diags.diagnose(SourceLoc(), diag::could_not_find_bridge_type,
input);
llvm::report_fatal_error("unable to set up the ObjC bridge!");
}
return loweredBridgedType->getCanonicalType();
}
Optional<ProtocolConformanceRef>
SubstitutionMap::forEachParent(CanType type, Fn fn) const {
auto foundParents = parentMap.find(type.getPointer());
if (foundParents != parentMap.end()) {
for (auto parent : foundParents->second) {
if (auto result = fn(parent.first, parent.second))
return result;
}
}
if (auto archetypeType = dyn_cast<ArchetypeType>(type))
if (auto *parent = archetypeType->getParent())
return fn(CanType(parent), archetypeType->getAssocType());
if (auto memberType = dyn_cast<DependentMemberType>(type))
return fn(CanType(memberType->getBase()), memberType->getAssocType());
return None;
}
// FIXME: With some changes to their callers, all of the below functions
// could be re-worked to use emitInjectEnum().
ManagedValue
SILGenFunction::emitInjectOptional(SILLocation loc,
ManagedValue v,
CanType inputFormalType,
CanType substFormalType,
const TypeLowering &expectedTL,
SGFContext ctxt) {
// Optional's payload is currently maximally abstracted. FIXME: Eventually
// it shouldn't be.
auto opaque = AbstractionPattern::getOpaque();
OptionalTypeKind substOTK;
auto substObjectType = substFormalType.getAnyOptionalObjectType(substOTK);
auto loweredTy = getLoweredType(opaque, substObjectType);
if (v.getType() != loweredTy)
v = emitTransformedValue(loc, v,
AbstractionPattern(inputFormalType), inputFormalType,
opaque, substObjectType);
auto someDecl = getASTContext().getOptionalSomeDecl(substOTK);
SILType optTy = getLoweredType(substFormalType);
if (v.getType().isAddress()) {
auto buf = getBufferForExprResult(loc, optTy.getObjectType(), ctxt);
auto payload = B.createInitEnumDataAddr(loc, buf, someDecl,
v.getType());
// FIXME: Is it correct to use IsTake here even if v doesn't have a cleanup?
B.createCopyAddr(loc, v.forward(*this), payload,
IsTake, IsInitialization);
B.createInjectEnumAddr(loc, buf, someDecl);
v = manageBufferForExprResult(buf, expectedTL, ctxt);
} else {
auto some = B.createEnum(loc, v.getValue(), someDecl, optTy);
v = ManagedValue(some, v.getCleanup());
}
return v;
}
/// Add a 32-bit relative offset to a mangled typeref string
/// in the typeref reflection section.
void addTypeRef(ModuleDecl *ModuleContext, CanType type,
CanGenericSignature Context = {}) {
assert(type);
// Generic parameters should be written in terms of interface types
// for the purposes of reflection metadata
assert(!type->hasArchetype() && "Forgot to map typeref out of context");
// TODO: As a compatibility hack, mangle single-field boxes with the legacy
// mangling in reflection metadata.
bool isSingleFieldOfBox = false;
auto boxTy = dyn_cast<SILBoxType>(type);
if (boxTy && boxTy->getLayout()->getFields().size() == 1) {
GenericContextScope scope(IGM, Context);
type = boxTy->getFieldLoweredType(IGM.getSILModule(), 0);
isSingleFieldOfBox = true;
}
IRGenMangler mangler;
std::string MangledStr = mangler.mangleTypeForReflection(type,
ModuleContext, isSingleFieldOfBox);
auto mangledName = IGM.getAddrOfStringForTypeRef(MangledStr);
addRelativeAddress(mangledName);
}
// Collect any builtin types referenced from this type.
void addBuiltinTypeRefs(CanType type) {
type.visit([&](Type t) {
if (t->is<BuiltinType>())
IGM.BuiltinTypes.insert(CanType(t));
// We need size/alignment information for imported value types,
// so emit builtin descriptors for them.
//
// In effect they're treated like an opaque blob, which is OK
// for now, at least until we want to import C++ types or
// something like that.
//
// Classes and protocols go down a different path.
if (auto Nominal = t->getAnyNominal())
if (Nominal->hasClangNode()) {
if (auto CD = dyn_cast<ClassDecl>(Nominal))
IGM.ImportedClasses.insert(CD);
else if (auto PD = dyn_cast<ProtocolDecl>(Nominal))
IGM.ImportedProtocols.insert(PD);
else
IGM.BuiltinTypes.insert(CanType(t));
}
});
}
/// Is metadata for the given type kind a "leaf", or does it possibly
/// store any other type metadata that we can statically extract?
///
/// It's okay to conservatively answer "no". It's more important for this
/// to be quick than for it to be accurate; don't recurse.
static bool isLeafTypeMetadata(CanType type) {
switch (type->getKind()) {
#define SUGARED_TYPE(ID, SUPER) \
case TypeKind::ID:
#define UNCHECKED_TYPE(ID, SUPER) \
case TypeKind::ID:
#define TYPE(ID, SUPER)
#include "swift/AST/TypeNodes.def"
llvm_unreachable("kind is invalid for a canonical type");
#define ARTIFICIAL_TYPE(ID, SUPER) \
case TypeKind::ID:
#define TYPE(ID, SUPER)
#include "swift/AST/TypeNodes.def"
case TypeKind::LValue:
case TypeKind::InOut:
case TypeKind::DynamicSelf:
llvm_unreachable("these types do not have metadata");
// All the builtin types are leaves.
#define BUILTIN_TYPE(ID, SUPER) \
case TypeKind::ID:
#define TYPE(ID, SUPER)
#include "swift/AST/TypeNodes.def"
case TypeKind::Module:
return true;
// Type parameters are statically opaque.
case TypeKind::Archetype:
case TypeKind::GenericTypeParam:
case TypeKind::DependentMember:
return true;
// Only the empty tuple is a leaf.
case TypeKind::Tuple:
return cast<TupleType>(type)->getNumElements() == 0;
// Nominal types might have parents.
case TypeKind::Class:
case TypeKind::Enum:
case TypeKind::Protocol:
case TypeKind::Struct:
return !cast<NominalType>(type)->getParent();
// Bound generic types have type arguments.
case TypeKind::BoundGenericClass:
case TypeKind::BoundGenericEnum:
case TypeKind::BoundGenericStruct:
return false;
// Functions have component types.
case TypeKind::Function:
case TypeKind::PolymorphicFunction:
case TypeKind::GenericFunction: // included for future-proofing
return false;
// Protocol compositions have component types.
case TypeKind::ProtocolComposition:
return false;
// Metatypes have instance types.
case TypeKind::Metatype:
case TypeKind::ExistentialMetatype:
return false;
}
llvm_unreachable("bad type kind");
}
// Start with the substitutions from the apply.
// Try to propagate them to find out the real substitutions required
// to invoke the method.
static ArrayRef<Substitution>
getSubstitutionsForCallee(SILModule &M, CanSILFunctionType GenCalleeType,
SILType ClassInstanceType, FullApplySite AI) {
// *NOTE*:
// Apply instruction substitutions are for the Member from a protocol or
// class B, where this member was first defined, before it got overridden by
// derived classes.
//
// The implementation F (the implementing method) which was found may have
// a different set of generic parameters, e.g. because it is implemented by a
// class D1 derived from B.
//
// ClassInstanceType may have a type different from both the type B
// the Member belongs to and from the ClassInstanceType, e.g. if
// ClassInstance is of a class D2, which is derived from D1, but does not
// override the Member.
//
// As a result, substitutions provided by AI are for Member, whereas
// substitutions in ClassInstanceType are for D2. And substitutions for D1
// are not available directly in a general case. Therefore, they have to
// be computed.
//
// What we know for sure:
// B is a superclass of D1
// D1 is a superclass of D2.
// D1 can be the same as D2. D1 can be the same as B.
//
// So, substitutions from AI are for class B.
// Substitutions for class D1 by means of bindSuperclass(), which starts
// with a bound type ClassInstanceType and checks its superclasses until it
// finds a bound superclass matching D1 and returns its substitutions.
// Class F belongs to.
CanType FSelfClass = GenCalleeType->getSelfParameter().getType();
SILType FSelfSubstType;
Module *Module = M.getSwiftModule();
ArrayRef<Substitution> ClassSubs;
if (GenCalleeType->isPolymorphic()) {
// Declaration of the class F belongs to.
if (auto *FSelfTypeDecl = FSelfClass.getNominalOrBoundGenericNominal()) {
// Get the unbound generic type F belongs to.
CanType FSelfGenericType =
FSelfTypeDecl->getDeclaredType()->getCanonicalType();
assert((isa<BoundGenericType>(ClassInstanceType.getSwiftRValueType()) ||
isa<NominalType>(ClassInstanceType.getSwiftRValueType())) &&
"Self type should be either a bound generic type"
"or a non-generic type");
assert((isa<UnboundGenericType>(FSelfGenericType) ||
isa<NominalType>(FSelfGenericType)) &&
"Method implementation self type should be generic");
if (isa<BoundGenericType>(ClassInstanceType.getSwiftRValueType())) {
auto BoundBaseType = bindSuperclass(FSelfGenericType,
ClassInstanceType);
if (auto BoundTy = BoundBaseType->getAs<BoundGenericType>()) {
ClassSubs = BoundTy->getSubstitutions(Module, nullptr);
}
}
}
} else {
// If the callee is not polymorphic, no substitutions are required.
return {};
}
if (ClassSubs.empty())
return AI.getSubstitutions();
auto AISubs = AI.getSubstitutions();
CanSILFunctionType AIGenCalleeType =
AI.getCallee().getType().castTo<SILFunctionType>();
CanType AISelfClass = AIGenCalleeType->getSelfParameter().getType();
unsigned NextMethodParamIdx = 0;
unsigned NumMethodParams = 0;
if (AIGenCalleeType->isPolymorphic()) {
NextMethodParamIdx = 0;
// Generic parameters of the method start after generic parameters
// of the instance class.
if (auto AISelfClassSig =
AISelfClass.getClassBound()->getGenericSignature()) {
NextMethodParamIdx = AISelfClassSig->getGenericParams().size();
}
NumMethodParams = AISubs.size() - NextMethodParamIdx;
}
unsigned NumSubs = ClassSubs.size() + NumMethodParams;
if (ClassSubs.size() == NumSubs)
return ClassSubs;
// Mix class subs with method specific subs from the AI substitutions.
// Assumptions: AI substitutions contain first the substitutions for
// a class of the method being invoked and then the substitutions
// for a method being invoked.
auto Subs = M.getASTContext().Allocate<Substitution>(NumSubs);
unsigned i = 0;
for (auto &S : ClassSubs) {
Subs[i++] = S;
}
for (; i < NumSubs; ++i, ++NextMethodParamIdx) {
Subs[i] = AISubs[NextMethodParamIdx];
}
return Subs;
}
void LocalTypeDataCache::
addAbstractForFulfillments(IRGenFunction &IGF, FulfillmentMap &&fulfillments,
llvm::function_ref<AbstractSource()> createSource) {
// Add the source lazily.
Optional<unsigned> sourceIndex;
auto getSourceIndex = [&]() -> unsigned {
if (!sourceIndex) {
AbstractSources.emplace_back(createSource());
sourceIndex = AbstractSources.size() - 1;
}
return *sourceIndex;
};
for (auto &fulfillment : fulfillments) {
CanType type = CanType(fulfillment.first.first);
LocalTypeDataKind localDataKind;
// For now, ignore witness-table fulfillments when they're not for
// archetypes.
if (ProtocolDecl *protocol = fulfillment.first.second) {
if (auto archetype = dyn_cast<ArchetypeType>(type)) {
auto conformsTo = archetype->getConformsTo();
auto it = std::find(conformsTo.begin(), conformsTo.end(), protocol);
if (it == conformsTo.end()) continue;
localDataKind = LocalTypeDataKind::forAbstractProtocolWitnessTable(*it);
} else {
continue;
}
} else {
// Ignore type metadata fulfillments for non-dependent types that
// we can produce very cheaply. We don't want to end up emitting
// the type metadata for Int by chasing through N layers of metadata
// just because that path happens to be in the cache.
if (!type->hasArchetype() &&
isTypeMetadataAccessTrivial(IGF.IGM, type)) {
continue;
}
localDataKind = LocalTypeDataKind::forTypeMetadata();
}
// Find the chain for the key.
auto key = getKey(type, localDataKind);
auto &chain = Map[key];
// Check whether there's already an entry that's at least as good as the
// fulfillment.
Optional<unsigned> fulfillmentCost;
auto getFulfillmentCost = [&]() -> unsigned {
if (!fulfillmentCost)
fulfillmentCost = fulfillment.second.Path.cost();
return *fulfillmentCost;
};
bool isConditional = IGF.isConditionalDominancePoint();
bool foundBetter = false;
for (CacheEntry *cur = chain.Root, *last = nullptr; cur;
last = cur, cur = cur->getNext()) {
// Ensure the entry is acceptable.
if (!IGF.isActiveDominancePointDominatedBy(cur->DefinitionPoint))
continue;
// Ensure that the entry isn't better than the fulfillment.
auto curCost = cur->cost();
if (curCost == 0 || curCost <= getFulfillmentCost()) {
foundBetter = true;
break;
}
// If the entry is defined at the current point, (1) we know there
// won't be a better entry and (2) we should remove it.
if (cur->DefinitionPoint == IGF.getActiveDominancePoint() &&
!isConditional) {
// Splice it out of the chain.
assert(!cur->isConditional());
chain.eraseEntry(last, cur);
break;
}
}
if (foundBetter) continue;
// Okay, make a new entry.
// Register with the conditional dominance scope if necessary.
if (isConditional) {
IGF.registerConditionalLocalTypeDataKey(key);
}
// Allocate the new entry.
auto newEntry = new AbstractCacheEntry(IGF.getActiveDominancePoint(),
isConditional,
getSourceIndex(),
std::move(fulfillment.second.Path));
// Add it to the front of the chain.
chain.push_front(newEntry);
}
}
/// Emit a single protocol witness table reference.
llvm::Value *irgen::emitArchetypeWitnessTableRef(IRGenFunction &IGF,
CanArchetypeType archetype,
ProtocolDecl *protocol) {
assert(Lowering::TypeConverter::protocolRequiresWitnessTable(protocol) &&
"looking up witness table for protocol that doesn't have one");
// The following approach assumes that a protocol will only appear in
// an archetype's conformsTo array if the archetype is either explicitly
// constrained to conform to that protocol (in which case we should have
// a cache entry for it) or there's an associated type declaration with
// that protocol listed as a direct requirement.
auto localDataKind =
LocalTypeDataKind::forAbstractProtocolWitnessTable(protocol);
// Check immediately for an existing cache entry.
// TODO: don't give this absolute precedence over other access paths.
auto wtable = IGF.tryGetLocalTypeData(archetype, localDataKind);
if (wtable) return wtable;
// If we don't have an environment, this must be an implied witness table
// reference.
// FIXME: eliminate this path when opened types have generic environments.
auto environment = archetype->getGenericEnvironment();
if (!environment) {
assert(archetype->isOpenedExistential() &&
"non-opened archetype lacking generic environment?");
SmallVector<ProtocolEntry, 4> entries;
for (auto p : archetype->getConformsTo()) {
const ProtocolInfo &impl =
IGF.IGM.getProtocolInfo(p, ProtocolInfoKind::RequirementSignature);
entries.push_back(ProtocolEntry(p, impl));
}
return emitImpliedWitnessTableRef(IGF, entries, protocol,
[&](unsigned index) -> llvm::Value* {
auto localDataKind =
LocalTypeDataKind::forAbstractProtocolWitnessTable(
entries[index].getProtocol());
auto wtable = IGF.tryGetLocalTypeData(archetype, localDataKind);
assert(wtable &&
"opened type without local type data for direct conformance?");
return wtable;
});
}
// Otherwise, ask the generic signature for the environment for the best
// path to the conformance.
// TODO: this isn't necessarily optimal if the direct conformance isn't
// concretely available; we really ought to be comparing the full paths
// to this conformance from concrete sources.
auto signature = environment->getGenericSignature()->getCanonicalSignature();
auto archetypeDepType = archetype->getInterfaceType();
auto astPath = signature->getConformanceAccessPath(archetypeDepType,
protocol);
auto i = astPath.begin(), e = astPath.end();
assert(i != e && "empty path!");
// The first entry in the path is a direct requirement of the signature,
// for which we should always have local type data available.
CanType rootArchetype =
environment->mapTypeIntoContext(i->first)->getCanonicalType();
ProtocolDecl *rootProtocol = i->second;
// Turn the rest of the path into a MetadataPath.
auto lastProtocol = rootProtocol;
MetadataPath path;
while (++i != e) {
auto &entry = *i;
CanType depType = CanType(entry.first);
ProtocolDecl *requirement = entry.second;
const ProtocolInfo &lastPI =
IGF.IGM.getProtocolInfo(lastProtocol,
ProtocolInfoKind::RequirementSignature);
// If it's a type parameter, it's self, and this is a base protocol
// requirement.
if (isa<GenericTypeParamType>(depType)) {
assert(depType->isEqual(lastProtocol->getSelfInterfaceType()));
WitnessIndex index = lastPI.getBaseIndex(requirement);
path.addInheritedProtocolComponent(index);
// Otherwise, it's an associated conformance requirement.
} else {
AssociatedConformance association(lastProtocol, depType, requirement);
WitnessIndex index = lastPI.getAssociatedConformanceIndex(association);
path.addAssociatedConformanceComponent(index);
}
lastProtocol = requirement;
}
assert(lastProtocol == protocol);
auto rootWTable = IGF.tryGetLocalTypeData(rootArchetype,
LocalTypeDataKind::forAbstractProtocolWitnessTable(rootProtocol));
assert(rootWTable && "root witness table not bound in local context!");
wtable = path.followFromWitnessTable(IGF, rootArchetype,
ProtocolConformanceRef(rootProtocol),
MetadataResponse::forComplete(rootWTable),
/*request*/ MetadataState::Complete,
nullptr).getMetadata();
return wtable;
}
Optional<T> SubstitutionMap::forEachConformance(
CanType type,
llvm::SmallPtrSetImpl<CanType> &visitedParents,
llvm::function_ref<Optional<T>(ProtocolConformanceRef)> fn) const{
// Check for conformances for the type that apply to the original
// substituted archetype.
auto foundReplacement = conformanceMap.find(type.getPointer());
if (foundReplacement != conformanceMap.end()) {
for (auto conformance : foundReplacement->second) {
if (auto found = fn(conformance))
return found;
}
}
// Local function to performance a (recursive) search for an associated type
// of the given name in the given conformance and all inherited conformances.
std::function<Optional<T>(ProtocolConformanceRef, DeclName,
llvm::SmallPtrSetImpl<ProtocolDecl *> &)>
searchInConformance;
searchInConformance =
[&](ProtocolConformanceRef conformance,
DeclName associatedTypeName,
llvm::SmallPtrSetImpl<ProtocolDecl *> &visited) -> Optional<T> {
// Only visit a particular protocol once.
auto proto = conformance.getRequirement();
if (!visited.insert(proto).second) return None;
// Check whether this protocol has an associated type with the
// same name as the one we're looking for.
AssociatedTypeDecl *protoAssocType = nullptr;
for (auto member : proto->lookupDirect(associatedTypeName)) {
protoAssocType = dyn_cast<AssociatedTypeDecl>(member);
if (protoAssocType) break;
}
if (protoAssocType) {
if (conformance.isAbstract()) {
for (auto assocProto : protoAssocType->getConformingProtocols()) {
if (auto found = fn(ProtocolConformanceRef(assocProto)))
return found;
}
} else {
auto sub = conformance.getConcrete()->getTypeWitnessSubstAndDecl(
protoAssocType, nullptr).first;
for (auto subConformance : sub.getConformances()) {
if (auto found = fn(subConformance))
return found;
}
}
}
// Search inherited conformances.
for (auto inherited : proto->getInheritedProtocols(nullptr)) {
if (auto found = searchInConformance(conformance.getInherited(inherited),
associatedTypeName,
visited))
return found;
}
return None;
};
// Check if we have conformances from one of our parent types.
return forEachParent<ProtocolConformanceRef>(type, visitedParents,
[&](CanType parent, AssociatedTypeDecl *assocType)
-> Optional<ProtocolConformanceRef> {
return forEachConformance<T>(parent, visitedParents,
[&](ProtocolConformanceRef conformance) -> Optional<T> {
llvm::SmallPtrSet<ProtocolDecl *, 4> visited;
return searchInConformance(conformance, assocType->getFullName(),
visited);
});
});
}
void SubstitutionMap::
addParent(CanType type, CanType parent, AssociatedTypeDecl *assocType) {
assert(type && parent && assocType);
parentMap[type.getPointer()].push_back(std::make_pair(parent, assocType));
}
ArrayRef<ProtocolConformanceRef> SubstitutionMap::
getConformances(CanType type) const {
auto known = conformanceMap.find(type.getPointer());
if (known == conformanceMap.end()) return { };
return known->second;
}
/// Given that a type is not statically known to be an optional type, check whether
/// it might dynamically be an optional type.
static bool canDynamicallyBeOptionalType(CanType type) {
assert(!type.getAnyOptionalObjectType());
return (isa<ArchetypeType>(type) || type.isExistentialType())
&& !type.isAnyClassReferenceType();
}
ManagedValue SILGenFunction::emitExistentialErasure(
SILLocation loc,
CanType concreteFormalType,
const TypeLowering &concreteTL,
const TypeLowering &existentialTL,
ArrayRef<ProtocolConformanceRef> conformances,
SGFContext C,
llvm::function_ref<ManagedValue (SGFContext)> F,
bool allowEmbeddedNSError) {
// Mark the needed conformances as used.
for (auto conformance : conformances)
SGM.useConformance(conformance);
// If we're erasing to the 'Error' type, we might be able to get an NSError
// representation more efficiently.
auto &ctx = getASTContext();
auto nsError = ctx.getNSErrorDecl();
if (allowEmbeddedNSError && nsError &&
existentialTL.getSemanticType().getSwiftRValueType()->getAnyNominal() ==
ctx.getErrorDecl()) {
// Check whether the concrete type conforms to the _BridgedStoredNSError
// protocol. In that case, call the _nsError witness getter to extract the
// NSError directly.
auto conformance =
SGM.getConformanceToBridgedStoredNSError(loc, concreteFormalType);
CanType nsErrorType =
nsError->getDeclaredInterfaceType()->getCanonicalType();
ProtocolConformanceRef nsErrorConformances[1] = {
ProtocolConformanceRef(SGM.getNSErrorConformanceToError())
};
if (conformance && nsError && SGM.getNSErrorConformanceToError()) {
if (auto witness =
conformance->getWitness(SGM.getNSErrorRequirement(loc), nullptr)) {
// Create a reference to the getter witness.
SILDeclRef getter =
getGetterDeclRef(cast<VarDecl>(witness.getDecl()),
/*isDirectAccessorUse=*/true);
// Compute the substitutions.
ArrayRef<Substitution> substitutions =
concreteFormalType->gatherAllSubstitutions(
SGM.SwiftModule, nullptr);
// Emit the erasure, through the getter to _nsError.
return emitExistentialErasure(
loc, nsErrorType,
getTypeLowering(nsErrorType),
existentialTL,
ctx.AllocateCopy(nsErrorConformances),
C,
[&](SGFContext innerC) -> ManagedValue {
// Call the getter.
return emitGetAccessor(loc, getter, substitutions,
ArgumentSource(loc,
RValue(*this, loc,
concreteFormalType,
F(SGFContext()))),
/*isSuper=*/false,
/*isDirectAccessorUse=*/true,
RValue(), innerC)
.getAsSingleValue(*this, loc);
});
}
}
// Check whether the concrete type is an archetype. If so, call the
// _getEmbeddedNSError() witness to try to dig out the embedded NSError.
if (auto archetypeType = concreteFormalType->getAs<ArchetypeType>()) {
if (std::find(archetypeType->getConformsTo().begin(),
archetypeType->getConformsTo().end(),
ctx.getErrorDecl())
!= archetypeType->getConformsTo().end()) {
auto contBB = createBasicBlock();
auto isNotPresentBB = createBasicBlock();
auto isPresentBB = createBasicBlock();
SILValue existentialResult =
contBB->createBBArg(existentialTL.getLoweredType());
ProtocolConformanceRef trivialErrorConformances[1] = {
ProtocolConformanceRef(ctx.getErrorDecl())
};
Substitution substitutions[1] = {
Substitution(concreteFormalType,
ctx.AllocateCopy(trivialErrorConformances))
};
// Call swift_stdlib_getErrorEmbeddedNSError to attempt to extract an
// NSError from the value.
ManagedValue concreteValue = F(SGFContext());
ManagedValue potentialNSError =
emitApplyOfLibraryIntrinsic(loc,
SGM.getGetErrorEmbeddedNSError(loc),
ctx.AllocateCopy(substitutions),
{ concreteValue },
SGFContext())
.getAsSingleValue(*this, loc);
// Check whether we got an NSError back.
SILValue hasNSError =
emitDoesOptionalHaveValue(loc, potentialNSError.getValue());
B.createCondBranch(loc, hasNSError, isPresentBB, isNotPresentBB);
// If we did get an NSError, emit the existential erasure from that
// NSError.
B.emitBlock(isPresentBB);
SILValue branchArg;
{
// Don't allow cleanups to escape the conditional block.
FullExpr presentScope(Cleanups, CleanupLocation::get(loc));
// Emit the existential erasure from the NSError.
branchArg = emitExistentialErasure(
loc, nsErrorType,
getTypeLowering(nsErrorType),
existentialTL,
ctx.AllocateCopy(nsErrorConformances),
C,
[&](SGFContext innerC) -> ManagedValue {
// Pull the NSError object out of the optional result.
auto &inputTL = getTypeLowering(potentialNSError.getType());
auto nsErrorValue =
emitUncheckedGetOptionalValueFrom(loc, potentialNSError,
inputTL);
// Perform an unchecked cast down to NSError, because it was typed
// as 'AnyObject' for layering reasons.
return ManagedValue(B.createUncheckedRefCast(
loc,
nsErrorValue.getValue(),
getLoweredType(nsErrorType)),
nsErrorValue.getCleanup());
}).forward(*this);
}
B.createBranch(loc, contBB, branchArg);
// If we did not get an NSError, just directly emit the existential
// (recursively).
B.emitBlock(isNotPresentBB);
branchArg = emitExistentialErasure(loc, concreteFormalType, concreteTL,
existentialTL, conformances,
SGFContext(), F,
/*allowEmbeddedNSError=*/false)
.forward(*this);
B.createBranch(loc, contBB, branchArg);
// Continue.
B.emitBlock(contBB);
return emitManagedRValueWithCleanup(existentialResult, existentialTL);
}
}
}
switch (existentialTL.getLoweredType().getObjectType()
.getPreferredExistentialRepresentation(SGM.M, concreteFormalType)) {
case ExistentialRepresentation::None:
llvm_unreachable("not an existential type");
case ExistentialRepresentation::Metatype: {
assert(existentialTL.isLoadable());
SILValue metatype = F(SGFContext()).getUnmanagedValue();
assert(metatype->getType().castTo<AnyMetatypeType>()->getRepresentation()
== MetatypeRepresentation::Thick);
auto upcast =
B.createInitExistentialMetatype(loc, metatype,
existentialTL.getLoweredType(),
conformances);
return ManagedValue::forUnmanaged(upcast);
}
case ExistentialRepresentation::Class: {
assert(existentialTL.isLoadable());
ManagedValue sub = F(SGFContext());
SILValue v = B.createInitExistentialRef(loc,
existentialTL.getLoweredType(),
concreteFormalType,
sub.getValue(),
conformances);
return ManagedValue(v, sub.getCleanup());
}
case ExistentialRepresentation::Boxed: {
// Allocate the existential.
auto *existential = B.createAllocExistentialBox(loc,
existentialTL.getLoweredType(),
concreteFormalType,
conformances);
auto *valueAddr = B.createProjectExistentialBox(loc,
concreteTL.getLoweredType(),
existential);
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Boxed,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return emitManagedRValueWithCleanup(existential);
}
case ExistentialRepresentation::Opaque: {
// Allocate the existential.
SILValue existential =
getBufferForExprResult(loc, existentialTL.getLoweredType(), C);
// Allocate the concrete value inside the container.
SILValue valueAddr = B.createInitExistentialAddr(
loc, existential,
concreteFormalType,
concreteTL.getLoweredType(),
conformances);
// Initialize the concrete value in-place.
InitializationPtr init(
new ExistentialInitialization(existential, valueAddr, concreteFormalType,
ExistentialRepresentation::Opaque,
*this));
ManagedValue mv = F(SGFContext(init.get()));
if (!mv.isInContext()) {
mv.forwardInto(*this, loc, init->getAddress());
init->finishInitialization(*this);
}
return manageBufferForExprResult(existential, existentialTL, C);
}
}
}
/// Try to classify a conversion from non-existential type
/// into an existential type by performing a static check
/// of protocol conformances if it is possible.
static DynamicCastFeasibility
classifyDynamicCastToProtocol(ModuleDecl *M, CanType source, CanType target,
bool isWholeModuleOpts) {
assert(target.isExistentialType() &&
"target should be an existential type");
if (source == target)
return DynamicCastFeasibility::WillSucceed;
auto *TargetProtocol = cast_or_null<ProtocolDecl>(target.getAnyNominal());
if (!TargetProtocol)
return DynamicCastFeasibility::MaySucceed;
auto conformance = M->lookupConformance(source, TargetProtocol);
if (conformance) {
// A conditional conformance can have things that need to be evaluated
// dynamically.
if (conformance->getConditionalRequirements().empty())
return DynamicCastFeasibility::WillSucceed;
return DynamicCastFeasibility::MaySucceed;
}
auto *SourceNominalTy = source.getAnyNominal();
if (!SourceNominalTy)
return DynamicCastFeasibility::MaySucceed;
// If we are casting a protocol, then the cast will fail
// as we have not found any conformances and protocols cannot
// be extended currently.
// NOTE: If we allow protocol extensions in the future, this
// conditional statement should be removed.
if (isa<ProtocolType>(source)) {
return DynamicCastFeasibility::WillFail;
}
// If it is a class and it can be proven that this class and its
// superclasses cannot be extended, then it is safe to proceed.
// No need to check this for structs, as they do not have any
// superclasses.
if (auto *CD = source.getClassOrBoundGenericClass()) {
if (canClassOrSuperclassesHaveExtensions(CD, isWholeModuleOpts))
return DynamicCastFeasibility::MaySucceed;
// Derived types may conform to the protocol.
if (!CD->isFinal()) {
// TODO: If it is a private type or internal type and we
// can prove that there are no derived types conforming to a
// protocol, then we can still return WillFail.
return DynamicCastFeasibility::MaySucceed;
}
}
// If the source type is file-private or target protocol is file-private,
// then conformances cannot be changed at run-time, because only this
// file could have implemented them, but no conformances were found.
// Therefore it is safe to make a negative decision at compile-time.
if (SourceNominalTy->getEffectiveAccess() <= AccessLevel::FilePrivate ||
TargetProtocol->getEffectiveAccess() <= AccessLevel::FilePrivate) {
// This cast is always false. Replace it with a branch to the
// failure block.
return DynamicCastFeasibility::WillFail;
}
// AnyHashable is a special case: although it's a struct, there maybe another
// type conforming to it and to the TargetProtocol at the same time.
if (SourceNominalTy == SourceNominalTy->getASTContext().getAnyHashableDecl())
return DynamicCastFeasibility::MaySucceed;
// If we are in a whole-module compilation and
// if the source type is internal or target protocol is internal,
// then conformances cannot be changed at run-time, because only this
// module could have implemented them, but no conformances were found.
// Therefore it is safe to make a negative decision at compile-time.
if (isWholeModuleOpts &&
(SourceNominalTy->getEffectiveAccess() <= AccessLevel::Internal ||
TargetProtocol->getEffectiveAccess() <= AccessLevel::Internal)) {
return DynamicCastFeasibility::WillFail;
}
return DynamicCastFeasibility::MaySucceed;
}
/// Try to classify the dynamic-cast relationship between two types.
DynamicCastFeasibility
swift::classifyDynamicCast(ModuleDecl *M,
CanType source,
CanType target,
bool isSourceTypeExact,
bool isWholeModuleOpts) {
if (source == target) return DynamicCastFeasibility::WillSucceed;
auto sourceObject = source.getOptionalObjectType();
auto targetObject = target.getOptionalObjectType();
// A common level of optionality doesn't affect the feasibility,
// except that we can't fold things to failure because nil inhabits
// both types.
if (sourceObject && targetObject) {
return atWorst(classifyDynamicCast(M, sourceObject, targetObject),
DynamicCastFeasibility::MaySucceed);
// Casting to a more optional type follows the same rule unless we
// know that the source cannot dynamically be an optional value,
// in which case we'll always just cast and inject into an optional.
} else if (targetObject) {
auto result = classifyDynamicCast(M, source, targetObject,
/* isSourceTypeExact */ false,
isWholeModuleOpts);
if (canDynamicallyStoreOptional(source))
result = atWorst(result, DynamicCastFeasibility::MaySucceed);
return result;
// Casting to a less-optional type can always fail.
} else if (sourceObject) {
return atBest(classifyDynamicCast(M, sourceObject, target,
/* isSourceTypeExact */ false,
isWholeModuleOpts),
DynamicCastFeasibility::MaySucceed);
}
assert(!sourceObject && !targetObject);
// Assume that casts to or from existential types or involving
// dependent types can always succeed. This is over-conservative.
if (source->hasArchetype() || source.isExistentialType() ||
target->hasArchetype() || target.isExistentialType()) {
// Check conversions from non-protocol types into protocol types.
if (!source.isExistentialType() &&
target.isExistentialType())
return classifyDynamicCastToProtocol(M, source, target,
isWholeModuleOpts);
// Check conversions from protocol types to non-protocol types.
if (source.isExistentialType() &&
!target.isExistentialType())
return classifyDynamicCastFromProtocol(M, source, target,
isWholeModuleOpts);
return DynamicCastFeasibility::MaySucceed;
}
// Casts from AnyHashable.
if (auto sourceStruct = dyn_cast<StructType>(source)) {
if (sourceStruct->getDecl() == M->getASTContext().getAnyHashableDecl()) {
if (auto hashable = getHashableExistentialType(M)) {
// Succeeds if Hashable can be cast to the target type.
return classifyDynamicCastFromProtocol(M, hashable, target,
isWholeModuleOpts);
}
}
}
// Casts to AnyHashable.
if (auto targetStruct = dyn_cast<StructType>(target)) {
if (targetStruct->getDecl() == M->getASTContext().getAnyHashableDecl()) {
// Succeeds if the source type can be dynamically cast to Hashable.
// Hashable is not actually a legal existential type right now, but
// the check doesn't care about that.
if (auto hashable = getHashableExistentialType(M)) {
return classifyDynamicCastToProtocol(M, source, hashable,
isWholeModuleOpts);
}
}
}
// Metatype casts.
if (auto sourceMetatype = dyn_cast<AnyMetatypeType>(source)) {
auto targetMetatype = dyn_cast<AnyMetatypeType>(target);
if (!targetMetatype) return DynamicCastFeasibility::WillFail;
source = sourceMetatype.getInstanceType();
target = targetMetatype.getInstanceType();
if (source == target &&
targetMetatype.isAnyExistentialType() ==
sourceMetatype.isAnyExistentialType())
return DynamicCastFeasibility::WillSucceed;
// If the source and target are the same existential type, but the source is
// P.Protocol and the dest is P.Type, then we need to consider whether the
// protocol is self-conforming.
// The only cases where a protocol self-conforms are objc protocols, but
// we're going to expect P.Type to hold a class object. And this case
// doesn't matter since for a self-conforming protocol type there can't be
// any type-level methods.
// Thus we consider this kind of cast to always fail. The only exception
// from this rule is when the target is Any.Type, because *.Protocol
// can always be casted to Any.Type.
if (source->isAnyExistentialType() && isa<MetatypeType>(sourceMetatype) &&
isa<ExistentialMetatypeType>(targetMetatype)) {
return target->isAny() ? DynamicCastFeasibility::WillSucceed
: DynamicCastFeasibility::WillFail;
}
if (targetMetatype.isAnyExistentialType() &&
(isa<ProtocolType>(target) || isa<ProtocolCompositionType>(target))) {
auto Feasibility =
classifyDynamicCastToProtocol(M, source, target, isWholeModuleOpts);
// Cast from existential metatype to existential metatype may still
// succeed, even if we cannot prove anything statically.
if (Feasibility != DynamicCastFeasibility::WillFail ||
!sourceMetatype.isAnyExistentialType())
return Feasibility;
}
// If isSourceTypeExact is true, we know we are casting the result of a
// MetatypeInst instruction.
if (isSourceTypeExact) {
// If source or target are existentials, then it can be cast
// successfully only into itself.
if ((target.isAnyExistentialType() || source.isAnyExistentialType()) &&
target != source)
return DynamicCastFeasibility::WillFail;
}
// Casts from class existential metatype into a concrete non-class metatype
// can never succeed.
if (source->isClassExistentialType() &&
!target.isAnyExistentialType() &&
!target.getClassOrBoundGenericClass())
return DynamicCastFeasibility::WillFail;
// TODO: prove that some conversions to existential metatype will
// obviously succeed/fail.
// TODO: prove that some conversions from class existential metatype
// to a concrete non-class metatype will obviously fail.
// TODO: class metatype to/from AnyObject
// TODO: protocol concrete metatype to/from ObjCProtocol
if (isa<ExistentialMetatypeType>(sourceMetatype) ||
isa<ExistentialMetatypeType>(targetMetatype))
return (getAnyMetatypeDepth(source) == getAnyMetatypeDepth(target)
? DynamicCastFeasibility::MaySucceed
: DynamicCastFeasibility::WillFail);
// If both metatypes are class metatypes, check if classes can be
// cast.
if (source.getClassOrBoundGenericClass() &&
target.getClassOrBoundGenericClass())
return classifyClassHierarchyCast(source, target);
// Different structs cannot be cast to each other.
if (source.getStructOrBoundGenericStruct() &&
target.getStructOrBoundGenericStruct() &&
source != target)
return DynamicCastFeasibility::WillFail;
// Different enums cannot be cast to each other.
if (source.getEnumOrBoundGenericEnum() &&
target.getEnumOrBoundGenericEnum() &&
source != target)
return DynamicCastFeasibility::WillFail;
// If we don't know any better, assume that the cast may succeed.
return DynamicCastFeasibility::MaySucceed;
}
// Function casts.
if (auto sourceFunction = dyn_cast<FunctionType>(source)) {
if (auto targetFunction = dyn_cast<FunctionType>(target)) {
// A function cast can succeed if the function types can be identical,
// or if the target type is throwier than the original.
// A non-throwing source function can be cast to a throwing target type,
// but not vice versa.
if (sourceFunction->throws() && !targetFunction->throws())
return DynamicCastFeasibility::WillFail;
// The cast can't change the representation at runtime.
if (targetFunction->getRepresentation()
!= sourceFunction->getRepresentation())
return DynamicCastFeasibility::WillFail;
if (sourceFunction.getInput() == targetFunction.getInput()
&& sourceFunction.getResult() == targetFunction.getResult())
return DynamicCastFeasibility::WillSucceed;
auto isSubstitutable = [](CanType a, CanType b) -> bool {
// FIXME: Unnecessarily conservative; should structurally check for
// substitutability.
return a == b || a->hasArchetype() || b->hasArchetype();
};
if (isSubstitutable(sourceFunction.getInput(), targetFunction.getInput())
&& isSubstitutable(targetFunction.getInput(),
targetFunction.getResult()))
return DynamicCastFeasibility::MaySucceed;
return DynamicCastFeasibility::WillFail;
}
}
// Tuple casts.
if (auto sourceTuple = dyn_cast<TupleType>(source)) {
if (auto targetTuple = dyn_cast<TupleType>(target)) {
// # of elements must coincide.
if (sourceTuple->getNumElements() != targetTuple->getNumElements())
return DynamicCastFeasibility::WillFail;
DynamicCastFeasibility result = DynamicCastFeasibility::WillSucceed;
for (unsigned i : range(sourceTuple->getNumElements())) {
const auto &sourceElt = sourceTuple->getElement(i);
const auto &targetElt = targetTuple->getElement(i);
// If both have names and the names mismatch, the cast will fail.
if (sourceElt.hasName() && targetElt.hasName() &&
sourceElt.getName() != targetElt.getName())
return DynamicCastFeasibility::WillFail;
// Combine the result of prior elements with this element type.
result = std::max(result,
classifyDynamicCast(M,
sourceElt.getType()->getCanonicalType(),
targetElt.getType()->getCanonicalType(),
isSourceTypeExact,
isWholeModuleOpts));
// If this element failed, we're done.
if (result == DynamicCastFeasibility::WillFail)
break;
}
return result;
}
}
// Class casts.
auto sourceClass = source.getClassOrBoundGenericClass();
auto targetClass = target.getClassOrBoundGenericClass();
if (sourceClass) {
if (targetClass) {
// Imported Objective-C generics don't check the generic parameters, which
// are lost at runtime.
if (sourceClass->usesObjCGenericsModel()) {
if (sourceClass == targetClass)
return DynamicCastFeasibility::WillSucceed;
if (targetClass->usesObjCGenericsModel()) {
// If both classes are ObjC generics, the cast may succeed if the
// classes are related, irrespective of their generic parameters.
auto isDeclSuperclass = [&](ClassDecl *proposedSuper,
ClassDecl *proposedSub) -> bool {
do {
if (proposedSuper == proposedSub)
return true;
} while ((proposedSub = proposedSub->getSuperclassDecl()));
return false;
};
if (isDeclSuperclass(sourceClass, targetClass))
return DynamicCastFeasibility::MaySucceed;
if (isDeclSuperclass(targetClass, sourceClass)) {
return DynamicCastFeasibility::WillSucceed;
}
return DynamicCastFeasibility::WillFail;
}
}
// Try a hierarchy cast. If that isn't failure, we can report it.
auto hierarchyResult = classifyClassHierarchyCast(source, target);
if (hierarchyResult != DynamicCastFeasibility::WillFail)
return hierarchyResult;
// As a backup, consider whether either type is a CF class type
// with an NS bridged equivalent.
CanType bridgedSource = getNSBridgedClassOfCFClass(M, source);
CanType bridgedTarget = getNSBridgedClassOfCFClass(M, target);
// If neither type qualifies, we're done.
if (!bridgedSource && !bridgedTarget)
return DynamicCastFeasibility::WillFail;
// Otherwise, map over to the bridged types and try to answer the
// question there.
if (bridgedSource) source = bridgedSource;
if (bridgedTarget) target = bridgedTarget;
return classifyDynamicCast(M, source, target, false, isWholeModuleOpts);
}
// Casts from a class into a non-class can never succeed if the target must
// be bridged to a SwiftValueBox. You would need an AnyObject source for
// that.
if (!target.isAnyExistentialType() &&
!target.getClassOrBoundGenericClass() &&
!isa<ArchetypeType>(target) &&
mustBridgeToSwiftValueBox(M, target)) {
assert((target.getEnumOrBoundGenericEnum() ||
target.getStructOrBoundGenericStruct() ||
isa<TupleType>(target) ||
isa<SILFunctionType>(target) ||
isa<FunctionType>(target) ||
isa<MetatypeType>(target)) &&
"Target should be an enum, struct, tuple, metatype or function type");
return DynamicCastFeasibility::WillFail;
}
// In the Objective-C runtime, class metatypes are also class instances.
// The cast may succeed if the target type can be inhabited by a class
// metatype.
// TODO: Narrow this to the sourceClass being exactly NSObject.
if (M->getASTContext().LangOpts.EnableObjCInterop) {
if (auto targetMeta = dyn_cast<MetatypeType>(target)) {
if (isa<ArchetypeType>(targetMeta.getInstanceType())
|| targetMeta.getInstanceType()->mayHaveSuperclass())
return DynamicCastFeasibility::MaySucceed;
} else if (isa<ExistentialMetatypeType>(target)) {
return DynamicCastFeasibility::MaySucceed;
}
}
}
// If the source is not existential, an archetype, or (under the ObjC runtime)
// a class, and the destination is a metatype, there is no way the cast can
// succeed.
if (target->is<AnyMetatypeType>()) return DynamicCastFeasibility::WillFail;
// FIXME: Be more careful with bridging conversions from
// NSArray, NSDictionary and NSSet as they may fail?
// We know that a cast from Int -> class foobar will fail.
if (targetClass &&
!source.isAnyExistentialType() &&
!source.getClassOrBoundGenericClass() &&
!isa<ArchetypeType>(source) &&
mustBridgeToSwiftValueBox(M, source)) {
assert((source.getEnumOrBoundGenericEnum() ||
source.getStructOrBoundGenericStruct() ||
isa<TupleType>(source) ||
isa<SILFunctionType>(source) ||
isa<FunctionType>(source) ||
isa<MetatypeType>(source)) &&
"Source should be an enum, struct, tuple, metatype or function type");
return DynamicCastFeasibility::WillFail;
}
// Check if there might be a bridging conversion.
if (source->isBridgeableObjectType() && mayBridgeToObjectiveC(M, target)) {
// Try to get the ObjC type which is bridged to target type.
assert(!target.isAnyExistentialType());
// ObjC-to-Swift casts may fail. And in most cases it is impossible to
// statically predict the outcome. So, let's be conservative here.
return DynamicCastFeasibility::MaySucceed;
}
if (target->isBridgeableObjectType() && mayBridgeToObjectiveC(M, source)) {
// Try to get the ObjC type which is bridged to source type.
assert(!source.isAnyExistentialType());
if (Type ObjCTy = M->getASTContext().getBridgedToObjC(M, source)) {
// If the bridged ObjC type is known, check if
// this type can be cast into target type.
return classifyDynamicCast(M,
ObjCTy->getCanonicalType(),
target,
/* isSourceTypeExact */ false, isWholeModuleOpts);
}
return DynamicCastFeasibility::MaySucceed;
}
// Check if it is a cast between bridged error types.
if (isError(M, source) && isError(M, target)) {
// TODO: Cast to NSError succeeds always.
return DynamicCastFeasibility::MaySucceed;
}
// Check for a viable collection cast.
if (auto sourceStruct = dyn_cast<BoundGenericStructType>(source)) {
if (auto targetStruct = dyn_cast<BoundGenericStructType>(target)) {
// Both types have to be the same kind of collection.
auto typeDecl = sourceStruct->getDecl();
if (typeDecl == targetStruct->getDecl()) {
auto sourceArgs = sourceStruct.getGenericArgs();
auto targetArgs = targetStruct.getGenericArgs();
// Note that we can never say that a collection cast is impossible:
// a cast can always succeed on an empty collection.
// Arrays and sets.
if (typeDecl == M->getASTContext().getArrayDecl() ||
typeDecl == M->getASTContext().getSetDecl()) {
auto valueFeasibility =
classifyDynamicCast(M, sourceArgs[0], targetArgs[0]);
return atWorst(valueFeasibility,
DynamicCastFeasibility::MaySucceed);
// Dictionaries.
} else if (typeDecl == M->getASTContext().getDictionaryDecl()) {
auto keyFeasibility =
classifyDynamicCast(M, sourceArgs[0], targetArgs[0]);
auto valueFeasibility =
classifyDynamicCast(M, sourceArgs[1], targetArgs[1]);
return atWorst(atBest(keyFeasibility, valueFeasibility),
DynamicCastFeasibility::MaySucceed);
}
}
}
}
return DynamicCastFeasibility::WillFail;
}
/// Given that a type is not statically known to be an optional type, check
/// whether it might dynamically be able to store an optional.
static bool canDynamicallyStoreOptional(CanType type) {
assert(!type.getOptionalObjectType());
return type->canDynamicallyBeOptionalType(/* includeExistential */ true);
}
/// Can the given cast be performed by the scalar checked-cast
/// instructions?
bool swift::canUseScalarCheckedCastInstructions(SILModule &M,
CanType sourceType,
CanType targetType) {
// Look through one level of optionality on the source.
auto objectType = sourceType;
if (auto type = objectType.getOptionalObjectType())
objectType = type;
// Casting to NSError needs to go through the indirect-cast case,
// since it may conform to Error and require Error-to-NSError
// bridging, unless we can statically see that the source type inherits
// NSError.
// A class-constrained archetype may be bound to NSError, unless it has a
// non-NSError superclass constraint. Casts to archetypes thus must always be
// indirect.
if (auto archetype = targetType->getAs<ArchetypeType>()) {
// Only ever permit this if the source type is a reference type.
if (!objectType.isAnyClassReferenceType())
return false;
if (M.getASTContext().LangOpts.EnableObjCInterop) {
auto super = archetype->getSuperclass();
if (super.isNull())
return false;
// A base class constraint that isn't NSError rules out the archetype being
// bound to NSError.
if (auto nserror = M.Types.getNSErrorType())
return !super->isEqual(nserror);
// If NSError wasn't loaded, any base class constraint must not be NSError.
return true;
} else {
// If ObjC bridging isn't enabled, we can do a scalar cast from any
// reference type to any class-constrained archetype.
return archetype->requiresClass();
}
}
if (M.getASTContext().LangOpts.EnableObjCInterop
&& targetType == M.Types.getNSErrorType()) {
// If we statically know the source is an NSError subclass, then the cast
// can go through the scalar path (and it's trivially true so can be
// killed).
return targetType->isExactSuperclassOf(objectType);
}
// Three supported cases:
// - metatype to metatype
// - metatype to object
// - object to object
if ((objectType.isAnyClassReferenceType() || isa<AnyMetatypeType>(objectType))
&& targetType.isAnyClassReferenceType())
return true;
if (isa<AnyMetatypeType>(objectType) && isa<AnyMetatypeType>(targetType))
return true;
// Otherwise, we need to use the general indirect-cast functions.
return false;
}
/// Propagate information about a concrete type from init_existential_addr
/// or init_existential_ref into witness_method conformances and into
/// apply instructions.
/// This helps the devirtualizer to replace witness_method by
/// class_method instructions and then devirtualize.
SILInstruction *
SILCombiner::propagateConcreteTypeOfInitExistential(FullApplySite AI,
ProtocolDecl *Protocol,
llvm::function_ref<void(CanType , ProtocolConformanceRef)> Propagate) {
// Get the self argument.
SILValue Self;
if (auto *Apply = dyn_cast<ApplyInst>(AI)) {
if (Apply->hasSelfArgument())
Self = Apply->getSelfArgument();
} else if (auto *Apply = dyn_cast<TryApplyInst>(AI)) {
if (Apply->hasSelfArgument())
Self = Apply->getSelfArgument();
}
assert(Self && "Self argument should be present");
// Try to find the init_existential, which could be used to
// determine a concrete type of the self.
CanType OpenedArchetype;
SILValue OpenedArchetypeDef;
SILInstruction *InitExistential =
findInitExistential(AI, Self, OpenedArchetype, OpenedArchetypeDef);
if (!InitExistential)
return nullptr;
// Try to derive the concrete type of self and a related conformance from
// the found init_existential.
ArrayRef<ProtocolConformanceRef> Conformances;
auto NewSelf = SILValue();
auto ConformanceAndConcreteType =
getConformanceAndConcreteType(AI, InitExistential,
Protocol, NewSelf, Conformances);
if (!ConformanceAndConcreteType)
return nullptr;
ProtocolConformanceRef Conformance = std::get<0>(*ConformanceAndConcreteType);
CanType ConcreteType = std::get<1>(*ConformanceAndConcreteType);
SILValue ConcreteTypeDef = std::get<2>(*ConformanceAndConcreteType);
SILOpenedArchetypesTracker *OldOpenedArchetypesTracker =
Builder.getOpenedArchetypesTracker();
SILOpenedArchetypesTracker OpenedArchetypesTracker(*AI.getFunction());
if (ConcreteType->isOpenedExistential()) {
// Prepare a mini-mapping for opened archetypes.
// SILOpenedArchetypesTracker OpenedArchetypesTracker(*AI.getFunction());
OpenedArchetypesTracker.addOpenedArchetypeDef(ConcreteType, ConcreteTypeDef);
Builder.setOpenedArchetypesTracker(&OpenedArchetypesTracker);
}
// Propagate the concrete type into the callee-operand if required.
Propagate(ConcreteType, Conformance);
// Create a new apply instruction that uses the concrete type instead
// of the existential type.
auto *NewAI = createApplyWithConcreteType(AI, NewSelf, Self, ConcreteType,
ConcreteTypeDef, Conformance,
OpenedArchetype);
if (ConcreteType->isOpenedExistential())
Builder.setOpenedArchetypesTracker(OldOpenedArchetypesTracker);
return NewAI;
}
clang::CanQualType
ClangTypeConverter::reverseBuiltinTypeMapping(IRGenModule &IGM,
CanStructType type) {
// Handle builtin types by adding entries to the cache that reverse
// the mapping done by the importer. We could try to look at the
// members of the struct instead, but even if that's ABI-equivalent
// (which it had better be!), it might erase interesting semantic
// differences like integers vs. characters. This is important
// because CC lowering isn't the only purpose of this conversion.
//
// The importer maps builtin types like 'int' to named types like
// 'CInt', which are generally typealiases. So what we do here is
// map the underlying types of those typealiases back to the builtin
// type. These typealiases frequently create a many-to-one mapping,
// so just use the first type that mapped to a particular underlying
// type.
//
// This is the last thing that happens before asserting that the
// struct type doesn't have a mapping. Furthermore, all of the
// builtin types are pre-built in the clang ASTContext. So it's not
// really a significant performance problem to just cache all them
// right here; it makes making a few more entries in the cache than
// we really need, but it also means we won't end up repeating these
// stdlib lookups multiple times, and we have to perform multiple
// lookups anyway because the MAP_BUILTIN_TYPE database uses
// typealias names (like 'CInt') that aren't obviously associated
// with the underlying C library type.
auto stdlib = IGM.Context.getStdlibModule();
assert(stdlib && "translating stdlib type to C without stdlib module?");
auto &ctx = IGM.getClangASTContext();
auto cacheStdlibType = [&](StringRef swiftName,
clang::BuiltinType::Kind builtinKind) {
CanType swiftType = getNamedSwiftType(stdlib, swiftName);
if (!swiftType) return;
auto &sema = IGM.Context.getClangModuleLoader()->getClangSema();
// Handle Int and UInt specially. On Apple platforms, these correspond to
// the NSInteger and NSUInteger typedefs, so map them back to those typedefs
// if they're available, to ensure we get consistent ObjC @encode strings.
if (swiftType->getAnyNominal() == IGM.Context.getIntDecl()) {
if (auto NSIntegerTy = getClangBuiltinTypeFromTypedef(sema, "NSInteger")) {
Cache.insert({swiftType, NSIntegerTy});
return;
}
} else if (swiftType->getAnyNominal() == IGM.Context.getUIntDecl()) {
if (auto NSUIntegerTy =
getClangBuiltinTypeFromTypedef(sema, "NSUInteger")) {
Cache.insert({swiftType, NSUIntegerTy});
return;
}
}
Cache.insert({swiftType, getClangBuiltinTypeFromKind(ctx, builtinKind)});
};
#define MAP_BUILTIN_TYPE(CLANG_BUILTIN_KIND, SWIFT_TYPE_NAME) \
cacheStdlibType(#SWIFT_TYPE_NAME, clang::BuiltinType::CLANG_BUILTIN_KIND);
#include "swift/ClangImporter/BuiltinMappedTypes.def"
// The above code sets up a bunch of mappings in the cache; just
// assume that we hit one of them.
auto it = Cache.find(type);
assert(it != Cache.end() &&
"cannot translate Swift type to C! type is not specially known");
return it->second;
}
void SubstitutionMap::
addConformance(CanType type, ProtocolConformanceRef conformance) {
conformanceMap[type.getPointer()].push_back(conformance);
}
