Revert "[metadata prespecialization] Support for classes."

include/swift/ABI/Metadata.h

@@ -1025,7 +1025,7 @@ struct TargetAnyClassMetadata : public TargetHeapMetadata<Runtime> {
   using TargetMetadata<Runtime>::setClassISA;
 #endif
 
-  // Note that ObjC classes do not have a metadata header.
+  // Note that ObjC classes does not have a metadata header.
 
   /// The metadata for the superclass.  This is null for the root class.
   ConstTargetMetadataPointer<Runtime, swift::TargetClassMetadata> Superclass;

include/swift/AST/Types.h

@@ -852,17 +852,7 @@ class alignas(1 << TypeAlignInBits) TypeBase {
   /// \returns The superclass of this type, or a null type if it has no
   ///          superclass.
   Type getSuperclass(bool useArchetypes = true);
-
-  /// Retrieve the root class of this type by repeatedly retrieving the
-  /// superclass.
-  ///
-  /// \param useArchetypes Whether to use context archetypes for outer generic
-  /// parameters if the class is nested inside a generic function.
-  ///
-  /// \returns The base class of this type, or this type itself if it has no
-  ///          superclasses.
-  Type getRootClass(bool useArchetypes = true);
-
+
   /// True if this type is the exact superclass of another type.
   ///
   /// \param ty       The potential subclass.

include/swift/Demangling/DemangleNodes.def

@@ -287,9 +287,5 @@ NODE(OpaqueTypeDescriptorAccessorVar)
 NODE(OpaqueReturnType)
 CONTEXT_NODE(OpaqueReturnTypeOf)
 
-// Added in Swift 5.3
-NODE(CanonicalSpecializedGenericMetaclass)
-NODE(CanonicalSpecializedGenericTypeMetadataAccessFunction)
-
 #undef CONTEXT_NODE
 #undef NODE

include/swift/IRGen/Linking.h

@@ -193,7 +193,7 @@ class LinkEntity {
     /// The nominal type descriptor for a nominal type.
     /// The pointer is a NominalTypeDecl*.
     NominalTypeDescriptor,
-
+    
     /// The descriptor for an opaque type.
     /// The pointer is an OpaqueTypeDecl*.
     OpaqueTypeDescriptor,
@@ -295,12 +295,12 @@ class LinkEntity {
     /// The descriptor for an extension.
     /// The pointer is an ExtensionDecl*.
     ExtensionDescriptor,
-
+    
     /// The descriptor for a runtime-anonymous context.
     /// The pointer is the DeclContext* of a child of the context that should
     /// be considered private.
     AnonymousDescriptor,
-
+    
     /// A SIL global variable. The pointer is a SILGlobalVariable*.
     SILGlobalVariable,
 
@@ -384,15 +384,6 @@ class LinkEntity {
 
     /// A global function pointer for dynamically replaceable functions.
     DynamicallyReplaceableFunctionVariable,
-
-    /// A reference to a metaclass-stub for a statically specialized generic
-    /// class.
-    /// The pointer is a canonical TypeBase*.
-    CanonicalSpecializedGenericSwiftMetaclassStub,
-
-    /// An access function for prespecialized type metadata.
-    /// The pointer is a canonical TypeBase*.
-    CanonicalSpecializedGenericTypeMetadataAccessFunction,
   };
   friend struct llvm::DenseMapInfo<LinkEntity>;
 
@@ -1029,22 +1020,6 @@ class LinkEntity {
     return entity;
   }
 
-  static LinkEntity
-  forSpecializedGenericSwiftMetaclassStub(CanType concreteType) {
-    LinkEntity entity;
-    entity.setForType(Kind::CanonicalSpecializedGenericSwiftMetaclassStub,
-                      concreteType);
-    return entity;
-  }
-
-  static LinkEntity
-  forPrespecializedTypeMetadataAccessFunction(CanType theType) {
-    LinkEntity entity;
-    entity.setForType(
-        Kind::CanonicalSpecializedGenericTypeMetadataAccessFunction, theType);
-    return entity;
-  }
-
   void mangle(llvm::raw_ostream &out) const;
   void mangle(SmallVectorImpl<char> &buffer) const;
   std::string mangleAsString() const;

lib/AST/Type.cpp

@@ -1552,17 +1552,6 @@ Type TypeBase::getSuperclass(bool useArchetypes) {
   return superclassTy.subst(subMap);
 }
 
-Type TypeBase::getRootClass(bool useArchetypes) {
-  Type iterator = this;
-  assert(iterator);
-
-  while (auto superclass = iterator->getSuperclass(useArchetypes)) {
-    iterator = superclass;
-  }
-
-  return iterator;
-}
-
 bool TypeBase::isExactSuperclassOf(Type ty) {
   // For there to be a superclass relationship, we must be a class, and
   // the potential subtype must be a class, superclass-bounded archetype,

lib/Demangling/Demangler.cpp

@@ -1874,9 +1874,6 @@ NodePointer Demangler::demangleMetatype() {
     case 'A':
       return createWithChild(Node::Kind::ReflectionMetadataAssocTypeDescriptor,
                              popProtocolConformance());
-    case 'b':
-      return createWithPoppedType(
-          Node::Kind::CanonicalSpecializedGenericTypeMetadataAccessFunction);
     case 'B':
       return createWithChild(Node::Kind::ReflectionMetadataBuiltinDescriptor,
                                popNode(Node::Kind::Type));
@@ -1920,9 +1917,6 @@ NodePointer Demangler::demangleMetatype() {
       return createWithPoppedType(Node::Kind::TypeMetadataLazyCache);
     case 'm':
       return createWithPoppedType(Node::Kind::Metaclass);
-    case 'M':
-      return createWithPoppedType(
-          Node::Kind::CanonicalSpecializedGenericMetaclass);
     case 'n':
       return createWithPoppedType(Node::Kind::NominalTypeDescriptor);
     case 'o':

lib/Demangling/NodePrinter.cpp

@@ -540,8 +540,6 @@ class NodePrinter {
     case Node::Kind::OpaqueTypeDescriptorSymbolicReference:
     case Node::Kind::OpaqueReturnType:
     case Node::Kind::OpaqueReturnTypeOf:
-    case Node::Kind::CanonicalSpecializedGenericMetaclass:
-    case Node::Kind::CanonicalSpecializedGenericTypeMetadataAccessFunction:
       return false;
     }
     printer_unreachable("bad node kind");
@@ -2420,14 +2418,6 @@ NodePointer NodePrinter::print(NodePointer Node, bool asPrefixContext) {
   case Node::Kind::AccessorFunctionReference:
     Printer << "accessor function at " << Node->getIndex();
     return nullptr;
-  case Node::Kind::CanonicalSpecializedGenericMetaclass:
-    Printer << "specialized generic metaclass for ";
-    print(Node->getFirstChild());
-    return nullptr;
-  case Node::Kind::CanonicalSpecializedGenericTypeMetadataAccessFunction:
-    Printer << "canonical specialized generic type metadata accessor for ";
-    print(Node->getChild(0));
-    return nullptr;
   }
   printer_unreachable("bad node kind!");
 }

lib/Demangling/OldRemangler.cpp

@@ -2133,17 +2133,6 @@ void Remangler::mangleAccessorFunctionReference(Node *node) {
   unreachable("can't remangle");
 }
 
-void Remangler::mangleCanonicalSpecializedGenericMetaclass(Node *node) {
-  Buffer << "MM";
-  mangleSingleChildNode(node); // type
-}
-
-void Remangler::mangleCanonicalSpecializedGenericTypeMetadataAccessFunction(
-    Node *node) {
-  mangleSingleChildNode(node);
-  Buffer << "Mb";
-}
-
 /// The top-level interface to the remangler.
 std::string Demangle::mangleNodeOld(NodePointer node) {
   if (!node) return "";

lib/Demangling/Remangler.cpp

@@ -2533,17 +2533,6 @@ void Remangler::mangleAccessorFunctionReference(Node *node) {
   unreachable("can't remangle");
 }
 
-void Remangler::mangleCanonicalSpecializedGenericMetaclass(Node *node) {
-  mangleChildNodes(node);
-  Buffer << "MM";
-}
-
-void Remangler::mangleCanonicalSpecializedGenericTypeMetadataAccessFunction(
-    Node *node) {
-  mangleSingleChildNode(node);
-  Buffer << "Mb";
-}
-
 } // anonymous namespace
 
 /// The top-level interface to the remangler.