Implement TypeSystemSwiftTypeRef::GetReferentType()

rdar://68171397

Author: adrian-prantl

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.cpp

@@ -2518,7 +2518,21 @@ CompilerType TypeSystemSwiftTypeRef::GetErrorType() {
 
 CompilerType
 TypeSystemSwiftTypeRef::GetReferentType(opaque_compiler_type_t type) {
-  return m_swift_ast_context->GetReferentType(ReconstructType(type));
+  auto impl = [&]() -> CompilerType {
+    using namespace swift::Demangle;
+    Demangler dem;
+    NodePointer node = GetDemangledType(dem, AsMangledName(type));
+    if (!node ||
+        (node->getKind() != Node::Kind::Unowned &&
+         node->getKind() != Node::Kind::Unmanaged) ||
+        !node->hasChildren())
+      return {this, type};
+    node = node->getFirstChild();
+    if (!node || node->getKind() != Node::Kind::Type || !node->hasChildren())
+      return {this, type};
+    return RemangleAsType(dem, node);
+  };
+  VALIDATE_AND_RETURN(impl, GetReferentType, type, (ReconstructType(type)));
 }
 
 CompilerType

lldb/source/Target/SwiftLanguageRuntimeDynamicTypeResolution.cpp

@@ -999,6 +999,7 @@ llvm::Optional<uint64_t> SwiftLanguageRuntimeImpl::GetMemberVariableOffset(
 
 static CompilerType GetWeakReferent(TypeSystemSwiftTypeRef &ts,
                                     CompilerType type) {
+  // FIXME: This is very similar to TypeSystemSwiftTypeRef::GetReferentType().
   using namespace swift::Demangle;
   Demangler dem;
   auto mangled = type.GetMangledTypeName().GetStringRef();