/// 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");
}
