ASTDemangler: Implement DynamicSelfType

Author: slavapestov

include/swift/AST/ASTDemangler.h

@@ -104,6 +104,8 @@ class ASTBuilder {
 
   ProtocolDecl *createObjCProtocolDecl(StringRef name);
 
+  Type createDynamicSelfType(Type selfType);
+
   Type createForeignClassType(StringRef mangledName);
 
   Type getUnnamedForeignClassType();

include/swift/Demangling/TypeDecoder.h

@@ -288,7 +288,16 @@ class TypeDecoder {
 
       return BuiltType();
     }
+    case NodeKind::DynamicSelf: {
+      if (Node->getNumChildren() != 1)
+        return BuiltType();
+
+      auto selfType = decodeMangledType(Node->getChild(0));
+      if (!selfType)
+        return BuiltType();
 
+      return Builder.createDynamicSelfType(selfType);
+    }
     case NodeKind::DependentGenericParamType: {
       auto depth = Node->getChild(0)->getIndex();
       auto index = Node->getChild(1)->getIndex();

include/swift/Reflection/TypeRefBuilder.h

@@ -329,6 +329,11 @@ class TypeRefBuilder {
     return SILBoxTypeRef::create(*this, base);
   }
 
+  const TypeRef *createDynamicSelfType(const TypeRef *selfType) {
+    // TypeRefs should not contain DynamicSelfType.
+    return nullptr;
+  }
+
   const ObjCClassTypeRef *getUnnamedObjCClassType() {
     return createObjCClassType("");
   }

lib/AST/ASTDemangler.cpp

@@ -316,6 +316,10 @@ ProtocolDecl *ASTBuilder::createObjCProtocolDecl(StringRef name) {
   return nullptr;
 }
 
+Type ASTBuilder::createDynamicSelfType(Type selfType) {
+  return DynamicSelfType::get(selfType, Ctx);
+}
+
 Type ASTBuilder::createForeignClassType(StringRef mangledName) {
   auto typeDecl = createNominalTypeDecl(mangledName);
   if (!typeDecl) return Type();

stdlib/public/runtime/MetadataLookup.cpp

@@ -1120,6 +1120,11 @@ class DecodedMetadataBuilder {
                                             protocols.size(), protocols.data());
   }
 
+  BuiltType createDynamicSelfType(BuiltType selfType) const {
+    // Free-standing mangled type strings should not contain DynamicSelfType.
+    return BuiltType();
+  }
+
   BuiltType createGenericTypeParameterType(unsigned depth,
                                            unsigned index) const {
     // Use the callback, when provided.

test/TypeDecoder/dynamic_self.swift

@@ -0,0 +1,17 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-build-swift -emit-executable %s -g -o %t/dynamic_self -emit-module
+// RUN: sed -ne '/\/\/ *DEMANGLE: /s/\/\/ *DEMANGLE: *//p' < %s > %t/input
+// RUN: %lldb-moduleimport-test %t/dynamic_self -type-from-mangled=%t/input | %FileCheck %s
+
+class Me {
+  func mine() -> Self {
+    let metatype = type(of: self)
+    return metatype.init()
+  }
+
+  required init() {}
+}
+
+// DEMANGLE: $s12dynamic_self2MeCXDXMTD
+// CHECK: Self.Type