-ms-extensions: Implement __super scope specifier (PR13236).

We build a NestedNameSpecifier that records the CXXRecordDecl in which
__super appeared. Name lookup is performed in all base classes of the
recorded CXXRecordDecl. Use of __super is allowed only inside class and
member function scope.

llvm-svn: 218484

32 files changed, 307 insertions, 33 deletions

diff --git a/clang/include/clang/AST/DataRecursiveASTVisitor.h b/clang/include/clang/AST/DataRecursiveASTVisitor.h
index 8bb5a0fd25e..0d470891fa7 100644
--- a/clang/include/clang/AST/DataRecursiveASTVisitor.h
+++ b/clang/include/clang/AST/DataRecursiveASTVisitor.h
@@ -624,6 +624,7 @@ bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifier(
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     return true;
 
   case NestedNameSpecifier::TypeSpec:
@@ -648,6 +649,7 @@ bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifierLoc(
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     return true;
 
   case NestedNameSpecifier::TypeSpec:
diff --git a/clang/include/clang/AST/NestedNameSpecifier.h b/clang/include/clang/AST/NestedNameSpecifier.h
index fc719bdc16c..518f1232fe8 100644
--- a/clang/include/clang/AST/NestedNameSpecifier.h
+++ b/clang/include/clang/AST/NestedNameSpecifier.h
@@ -22,6 +22,7 @@
 namespace clang {
 
 class ASTContext;
+class CXXRecordDecl;
 class NamespaceAliasDecl;
 class NamespaceDecl;
 class IdentifierInfo;
@@ -45,7 +46,7 @@ class NestedNameSpecifier : public llvm::FoldingSetNode {
   /// \brief Enumeration describing
   enum StoredSpecifierKind {
     StoredIdentifier = 0,
-    StoredNamespaceOrAlias = 1,
+    StoredDecl = 1,
     StoredTypeSpec = 2,
     StoredTypeSpecWithTemplate = 3
   };
@@ -83,7 +84,10 @@ public:
     /// stored as a Type*.
     TypeSpecWithTemplate,
     /// \brief The global specifier '::'. There is no stored value.
-    Global
+    Global,
+    /// \brief Microsoft's '__super' specifier, stored as a CXXRecordDecl* of
+    /// the class it appeared in.
+    Super
   };
 
 private:
@@ -143,6 +147,11 @@ public:
   /// scope.
   static NestedNameSpecifier *GlobalSpecifier(const ASTContext &Context);
 
+  /// \brief Returns the nested name specifier representing the __super scope
+  /// for the given CXXRecordDecl.
+  static NestedNameSpecifier *SuperSpecifier(const ASTContext &Context,
+                                             CXXRecordDecl *RD);
+
   /// \brief Return the prefix of this nested name specifier.
   ///
   /// The prefix contains all of the parts of the nested name
@@ -172,6 +181,10 @@ public:
   /// specifier.
   NamespaceAliasDecl *getAsNamespaceAlias() const;
 
+  /// \brief Retrieve the record declaration stored in this nested name
+  /// specifier.
+  CXXRecordDecl *getAsRecordDecl() const;
+
   /// \brief Retrieve the type stored in this nested name specifier.
   const Type *getAsType() const {
     if (Prefix.getInt() == StoredTypeSpec ||
@@ -421,7 +434,22 @@ public:
   /// \brief Turn this (empty) nested-name-specifier into the global
   /// nested-name-specifier '::'.
   void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);
-
+  
+  /// \brief Turns this (empty) nested-name-specifier into '__super'
+  /// nested-name-specifier.
+  ///
+  /// \param Context The AST context in which this nested-name-specifier
+  /// resides.
+  ///
+  /// \param RD The declaration of the class in which nested-name-specifier
+  /// appeared.
+  ///
+  /// \param SuperLoc The location of the '__super' keyword.
+  /// name.
+  ///
+  /// \param ColonColonLoc The location of the trailing '::'.
+  void MakeSuper(ASTContext &Context, CXXRecordDecl *RD, 
+                 SourceLocation SuperLoc, SourceLocation ColonColonLoc);
   /// \brief Make a new nested-name-specifier from incomplete source-location
   /// information.
   ///
diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index e001cb65390..821eacb21f5 100644
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -690,6 +690,7 @@ bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifier(
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     return true;
 
   case NestedNameSpecifier::TypeSpec:
@@ -714,6 +715,7 @@ bool RecursiveASTVisitor<Derived>::TraverseNestedNameSpecifierLoc(
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     return true;
 
   case NestedNameSpecifier::TypeSpec:
diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index ff3e9a76bb6..cea0ebf5536 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -368,6 +368,8 @@ def err_function_definition_not_allowed : Error<
   "function definition is not allowed here">;
 def err_expected_end_of_enumerator : Error<
   "expected '= constant-expression' or end of enumerator definition">;
+def err_expected_coloncolon_after_super : Error<
+  "expected '::' after '__super'">;
 
 /// Objective-C parser diagnostics
 def err_expected_minus_or_plus : Error<
@@ -521,6 +523,8 @@ def ext_abstract_pack_declarator_parens : ExtWarn<
   InGroup<DiagGroup<"anonymous-pack-parens">>;
 def err_function_is_not_record : Error<
   "unexpected %0 in function call; perhaps remove the %0?">;
+def err_super_in_using_declaration : Error<
+  "'__super' cannot be used with a using declaration">;
 
 // C++ derived classes
 def err_dup_virtual : Error<"duplicate 'virtual' in base specifier">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 4daf3a28db3..2981fed51ff 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -531,6 +531,11 @@ def warn_cxx_ms_struct :
           "with base classes or virtual functions">,
   DefaultError, InGroup<IncompatibleMSStruct>;
 def err_section_conflict : Error<"%0 causes a section type conflict with %1">;
+def err_no_base_classes : Error<"invalid use of '__super', %0 has no base classes">;
+def err_invalid_super_scope : Error<"invalid use of '__super', "
+  "this keyword can only be used inside class or member function scope">;
+def err_super_in_lambda_unsupported : Error<
+  "use of '__super' inside a lambda is unsupported">;
 
 def warn_pragma_unused_undeclared_var : Warning<
   "undeclared variable %0 used as an argument for '#pragma unused'">,
diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def
index 5c49bcfd524..2ecc5f5dfa8 100644
--- a/clang/include/clang/Basic/TokenKinds.def
+++ b/clang/include/clang/Basic/TokenKinds.def
@@ -459,6 +459,7 @@ KEYWORD(__fastcall                  , KEYALL)
 KEYWORD(__thiscall                  , KEYALL)
 KEYWORD(__forceinline               , KEYMS)
 KEYWORD(__unaligned                 , KEYMS)
+KEYWORD(__super                     , KEYMS)
 
 // OpenCL address space qualifiers
 KEYWORD(__global                    , KEYOPENCL)
diff --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index 8364dfc4b0b..d438cc3b03f 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -37,6 +37,7 @@
 
 namespace clang {
   class ASTContext;
+  class CXXRecordDecl;
   class TypeLoc;
   class LangOptions;
   class DiagnosticsEngine;
@@ -141,6 +142,22 @@ public:
   /// nested-name-specifier '::'.
   void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);
   
+  /// \brief Turns this (empty) nested-name-specifier into '__super'
+  /// nested-name-specifier.
+  ///
+  /// \param Context The AST context in which this nested-name-specifier
+  /// resides.
+  ///
+  /// \param RD The declaration of the class in which nested-name-specifier
+  /// appeared.
+  ///
+  /// \param SuperLoc The location of the '__super' keyword.
+  /// name.
+  ///
+  /// \param ColonColonLoc The location of the trailing '::'.
+  void MakeSuper(ASTContext &Context, CXXRecordDecl *RD,
+                 SourceLocation SuperLoc, SourceLocation ColonColonLoc);
+
   /// \brief Make a new nested-name-specifier from incomplete source-location
   /// information.
   ///
diff --git a/clang/include/clang/Sema/Scope.h b/clang/include/clang/Sema/Scope.h
index 27067a11198..97e447d1fd6 100644
--- a/clang/include/clang/Sema/Scope.h
+++ b/clang/include/clang/Sema/Scope.h
@@ -300,6 +300,9 @@ public:
     return ErrorTrap.hasUnrecoverableErrorOccurred();
   }
 
+  /// isFunctionScope() - Return true if this scope is a function scope.
+  bool isFunctionScope() const { return (getFlags() & Scope::FnScope); }
+
   /// isClassScope - Return true if this scope is a class/struct/union scope.
   bool isClassScope() const {
     return (getFlags() & Scope::ClassScope);
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index fc19680c9cf..31aa600c181 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -2616,6 +2616,7 @@ public:
   ObjCProtocolDecl *LookupProtocol(IdentifierInfo *II, SourceLocation IdLoc,
                                    RedeclarationKind Redecl
                                      = NotForRedeclaration);
+  void LookupInSuper(LookupResult &R, CXXRecordDecl *Class);
 
   void LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S,
                                     QualType T1, QualType T2,
@@ -4482,16 +4483,26 @@ public:
 
   /// \brief The parser has parsed a global nested-name-specifier '::'.
   ///
-  /// \param S The scope in which this nested-name-specifier occurs.
-  ///
   /// \param CCLoc The location of the '::'.
   ///
   /// \param SS The nested-name-specifier, which will be updated in-place
   /// to reflect the parsed nested-name-specifier.
   ///
   /// \returns true if an error occurred, false otherwise.
-  bool ActOnCXXGlobalScopeSpecifier(Scope *S, SourceLocation CCLoc,
-                                    CXXScopeSpec &SS);
+  bool ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc, CXXScopeSpec &SS);
+
+  /// \brief The parser has parsed a '__super' nested-name-specifier.
+  ///
+  /// \param SuperLoc The location of the '__super' keyword.
+  ///
+  /// \param ColonColonLoc The location of the '::'.
+  ///
+  /// \param SS The nested-name-specifier, which will be updated in-place
+  /// to reflect the parsed nested-name-specifier.
+  ///
+  /// \returns true if an error occurred, false otherwise.
+  bool ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
+                                SourceLocation ColonColonLoc, CXXScopeSpec &SS);
 
   bool isAcceptableNestedNameSpecifier(const NamedDecl *SD);
   NamedDecl *FindFirstQualifierInScope(Scope *S, NestedNameSpecifier *NNS);
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index cafde32eb6f..7e5182e3397 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -4195,7 +4195,8 @@ ASTContext::getCanonicalNestedNameSpecifier(NestedNameSpecifier *NNS) const {
   }
 
   case NestedNameSpecifier::Global:
-    // The global specifier is canonical and unique.
+  case NestedNameSpecifier::Super:
+    // The global specifier and __super specifer are canonical and unique.
     return NNS;
   }
 
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 05f39abaa37..ca7ab63c96f 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -4760,6 +4760,13 @@ NestedNameSpecifier *ASTImporter::Import(NestedNameSpecifier *FromNNS) {
   case NestedNameSpecifier::Global:
     return NestedNameSpecifier::GlobalSpecifier(ToContext);
 
+  case NestedNameSpecifier::Super:
+    if (CXXRecordDecl *RD =
+            cast<CXXRecordDecl>(Import(FromNNS->getAsRecordDecl()))) {
+      return NestedNameSpecifier::SuperSpecifier(ToContext, RD);
+    }
+    return nullptr;
+
   case NestedNameSpecifier::TypeSpec:
   case NestedNameSpecifier::TypeSpecWithTemplate: {
       QualType T = Import(QualType(FromNNS->getAsType(), 0u));
diff --git a/clang/lib/AST/ExprCXX.cpp b/clang/lib/AST/ExprCXX.cpp
index 08230bebed1..93361666183 100644
--- a/clang/lib/AST/ExprCXX.cpp
+++ b/clang/lib/AST/ExprCXX.cpp
@@ -1404,7 +1404,8 @@ CXXRecordDecl *UnresolvedMemberExpr::getNamingClass() const {
   // It can't be dependent: after all, we were actually able to do the
   // lookup.
   CXXRecordDecl *Record = nullptr;
-  if (getQualifier()) {
+  auto *NNS = getQualifier();
+  if (NNS && NNS->getKind() != NestedNameSpecifier::Super) {
     const Type *T = getQualifier()->getAsType();
     assert(T && "qualifier in member expression does not name type");
     Record = T->getAsCXXRecordDecl();
diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 4717174b4a4..d2d02fac03e 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -814,6 +814,9 @@ void CXXNameMangler::mangleUnresolvedPrefix(NestedNameSpecifier *qualifier,
     // We never want an 'E' here.
     return;
 
+  case NestedNameSpecifier::Super:
+    llvm_unreachable("Can't mangle __super specifier");
+
   case NestedNameSpecifier::Namespace:
     if (qualifier->getPrefix())
       mangleUnresolvedPrefix(qualifier->getPrefix(), firstQualifierLookup,
@@ -1462,6 +1465,9 @@ void CXXNameMangler::manglePrefix(NestedNameSpecifier *qualifier) {
     // nothing
     return;
 
+  case NestedNameSpecifier::Super:
+    llvm_unreachable("Can't mangle __super specifier");
+
   case NestedNameSpecifier::Namespace:
     mangleName(qualifier->getAsNamespace());
     return;
diff --git a/clang/lib/AST/NestedNameSpecifier.cpp b/clang/lib/AST/NestedNameSpecifier.cpp
index 1f041aa4954..50a00502ca9 100644
--- a/clang/lib/AST/NestedNameSpecifier.cpp
+++ b/clang/lib/AST/NestedNameSpecifier.cpp
@@ -66,7 +66,7 @@ NestedNameSpecifier::Create(const ASTContext &Context,
          "Broken nested name specifier");
   NestedNameSpecifier Mockup;
   Mockup.Prefix.setPointer(Prefix);
-  Mockup.Prefix.setInt(StoredNamespaceOrAlias);
+  Mockup.Prefix.setInt(StoredDecl);
   Mockup.Specifier = const_cast<NamespaceDecl *>(NS);
   return FindOrInsert(Context, Mockup);
 }
@@ -82,7 +82,7 @@ NestedNameSpecifier::Create(const ASTContext &Context,
          "Broken nested name specifier");
   NestedNameSpecifier Mockup;
   Mockup.Prefix.setPointer(Prefix);
-  Mockup.Prefix.setInt(StoredNamespaceOrAlias);
+  Mockup.Prefix.setInt(StoredDecl);
   Mockup.Specifier = Alias;
   return FindOrInsert(Context, Mockup);
 }
@@ -118,6 +118,16 @@ NestedNameSpecifier::GlobalSpecifier(const ASTContext &Context) {
   return Context.GlobalNestedNameSpecifier;
 }
 
+NestedNameSpecifier *
+NestedNameSpecifier::SuperSpecifier(const ASTContext &Context,
+                                    CXXRecordDecl *RD) {
+  NestedNameSpecifier Mockup;
+  Mockup.Prefix.setPointer(nullptr);
+  Mockup.Prefix.setInt(StoredDecl);
+  Mockup.Specifier = RD;
+  return FindOrInsert(Context, Mockup);
+}
+
 NestedNameSpecifier::SpecifierKind NestedNameSpecifier::getKind() const {
   if (!Specifier)
     return Global;
@@ -126,9 +136,12 @@ NestedNameSpecifier::SpecifierKind NestedNameSpecifier::getKind() const {
   case StoredIdentifier:
     return Identifier;
 
-  case StoredNamespaceOrAlias:
-    return isa<NamespaceDecl>(static_cast<NamedDecl *>(Specifier))? Namespace
-                                                            : NamespaceAlias;
+  case StoredDecl: {
+    NamedDecl *ND = static_cast<NamedDecl *>(Specifier);
+    if (isa<CXXRecordDecl>(ND))
+      return Super;
+    return isa<NamespaceDecl>(ND) ? Namespace : NamespaceAlias;
+  }
 
   case StoredTypeSpec:
     return TypeSpec;
@@ -140,24 +153,29 @@ NestedNameSpecifier::SpecifierKind NestedNameSpecifier::getKind() const {
   llvm_unreachable("Invalid NNS Kind!");
 }
 
-/// \brief Retrieve the namespace stored in this nested name
-/// specifier.
+/// \brief Retrieve the namespace stored in this nested name specifier.
 NamespaceDecl *NestedNameSpecifier::getAsNamespace() const {
-  if (Prefix.getInt() == StoredNamespaceOrAlias)
+	if (Prefix.getInt() == StoredDecl)
     return dyn_cast<NamespaceDecl>(static_cast<NamedDecl *>(Specifier));
 
   return nullptr;
 }
 
-/// \brief Retrieve the namespace alias stored in this nested name
-/// specifier.
+/// \brief Retrieve the namespace alias stored in this nested name specifier.
 NamespaceAliasDecl *NestedNameSpecifier::getAsNamespaceAlias() const {
-  if (Prefix.getInt() == StoredNamespaceOrAlias)
+	if (Prefix.getInt() == StoredDecl)
     return dyn_cast<NamespaceAliasDecl>(static_cast<NamedDecl *>(Specifier));
 
   return nullptr;
 }
 
+/// \brief Retrieve the record declaration stored in this nested name specifier.
+CXXRecordDecl *NestedNameSpecifier::getAsRecordDecl() const {
+  if (Prefix.getInt() == StoredDecl)
+    return dyn_cast<CXXRecordDecl>(static_cast<NamedDecl *>(Specifier));
+
+  return nullptr;
+}
 
 /// \brief Whether this nested name specifier refers to a dependent
 /// type or not.
@@ -172,6 +190,15 @@ bool NestedNameSpecifier::isDependent() const {
   case Global:
     return false;
 
+  case Super: {
+    CXXRecordDecl *RD = static_cast<CXXRecordDecl *>(Specifier);
+    for (const auto &Base : RD->bases())
+      if (Base.getType()->isDependentType())
+        return true;
+
+    return false;
+  }
+
   case TypeSpec:
   case TypeSpecWithTemplate:
     return getAsType()->isDependentType();
@@ -191,8 +218,9 @@ bool NestedNameSpecifier::isInstantiationDependent() const {
   case Namespace:
   case NamespaceAlias:
   case Global:
+  case Super:
     return false;
-    
+
   case TypeSpec:
   case TypeSpecWithTemplate:
     return getAsType()->isInstantiationDependentType();
@@ -209,6 +237,7 @@ bool NestedNameSpecifier::containsUnexpandedParameterPack() const {
   case Namespace:
   case NamespaceAlias:
   case Global:
+  case Super:
     return false;
 
   case TypeSpec:
@@ -246,6 +275,10 @@ NestedNameSpecifier::print(raw_ostream &OS,
   case Global:
     break;
 
+  case Super:
+    OS << "__super";
+    break;
+
   case TypeSpecWithTemplate:
     OS << "template ";
     // Fall through to print the type.
@@ -304,6 +337,7 @@ NestedNameSpecifierLoc::getLocalDataLength(NestedNameSpecifier *Qualifier) {
   case NestedNameSpecifier::Identifier:
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
+  case NestedNameSpecifier::Super:
     // The location of the identifier or namespace name.
     Length += sizeof(unsigned);
     break;
@@ -369,6 +403,7 @@ SourceRange NestedNameSpecifierLoc::getLocalSourceRange() const {
   case NestedNameSpecifier::Identifier:
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
+  case NestedNameSpecifier::Super:
     return SourceRange(LoadSourceLocation(Data, Offset),
                        LoadSourceLocation(Data, Offset + sizeof(unsigned)));
 
@@ -552,6 +587,17 @@ void NestedNameSpecifierLocBuilder::MakeGlobal(ASTContext &Context,
   SaveSourceLocation(ColonColonLoc, Buffer, BufferSize, BufferCapacity);
 }
 
+void NestedNameSpecifierLocBuilder::MakeSuper(ASTContext &Context,
+                                              CXXRecordDecl *RD,
+                                              SourceLocation SuperLoc,
+                                              SourceLocation ColonColonLoc) {
+  Representation = NestedNameSpecifier::SuperSpecifier(Context, RD);
+
+  // Push source-location info into the buffer.
+  SaveSourceLocation(SuperLoc, Buffer, BufferSize, BufferCapacity);
+  SaveSourceLocation(ColonColonLoc, Buffer, BufferSize, BufferCapacity);
+}
+
 void NestedNameSpecifierLocBuilder::MakeTrivial(ASTContext &Context, 
                                                 NestedNameSpecifier *Qualifier, 
                                                 SourceRange R) {
@@ -583,6 +629,7 @@ void NestedNameSpecifierLocBuilder::MakeTrivial(ASTContext &Context,
       }
         
       case NestedNameSpecifier::Global:
+      case NestedNameSpecifier::Super:
         break;
     }
     
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 53e3dbea81f..569234bf558 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -2731,6 +2731,7 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
       goto DoneWithDeclSpec;
 
       // typedef-name
+    case tok::kw___super:
     case tok::kw_decltype:
     case tok::identifier: {
       // This identifier can only be a typedef name if we haven't already seen
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 362b2c04422..87b1dd89b7a 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -493,6 +493,12 @@ Decl *Parser::ParseUsingDeclaration(unsigned Context,
   if (TryConsumeToken(tok::kw_typename, TypenameLoc))
     HasTypenameKeyword = true;
 
+  if (Tok.is(tok::kw___super)) {
+    Diag(Tok.getLocation(), diag::err_super_in_using_declaration);
+    SkipUntil(tok::semi);
+    return nullptr;
+  }
+
   // Parse nested-name-specifier.
   IdentifierInfo *LastII = nullptr;
   ParseOptionalCXXScopeSpecifier(SS, ParsedType(), /*EnteringContext=*/false,
@@ -2101,7 +2107,8 @@ void Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
   // Access declarations.
   bool MalformedTypeSpec = false;
   if (!TemplateInfo.Kind &&
-      (Tok.is(tok::identifier) || Tok.is(tok::coloncolon))) {
+      (Tok.is(tok::identifier) || Tok.is(tok::coloncolon) ||
+       Tok.is(tok::kw___super))) {
     if (TryAnnotateCXXScopeToken())
       MalformedTypeSpec = true;
 
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index e121902bf0c..8f5a5cadf7d 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -688,11 +688,12 @@ ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
     ConsumeToken();
     break;
 
+  case tok::kw___super:
   case tok::kw_decltype:
     // Annotate the token and tail recurse.
     if (TryAnnotateTypeOrScopeToken())
       return ExprError();
-    assert(Tok.isNot(tok::kw_decltype));
+    assert(Tok.isNot(tok::kw_decltype) && Tok.isNot(tok::kw___super));
     return ParseCastExpression(isUnaryExpression, isAddressOfOperand);
       
   case tok::identifier: {      // primary-expression: identifier
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index cf0e4ce5c0c..8f22f5609e6 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -218,7 +218,7 @@ bool Parser::ParseOptionalCXXScopeSpecifier(CXXScopeSpec &SS,
       return false;
 
     // '::' - Global scope qualifier.
-    if (Actions.ActOnCXXGlobalScopeSpecifier(getCurScope(), ConsumeToken(), SS))
+    if (Actions.ActOnCXXGlobalScopeSpecifier(ConsumeToken(), SS))
       return true;
 
     CheckForLParenAfterColonColon();
@@ -226,6 +226,16 @@ bool Parser::ParseOptionalCXXScopeSpecifier(CXXScopeSpec &SS,
     HasScopeSpecifier = true;
   }
 
+  if (Tok.is(tok::kw___super)) {
+    SourceLocation SuperLoc = ConsumeToken();
+    if (!Tok.is(tok::coloncolon)) {
+      Diag(Tok.getLocation(), diag::err_expected_coloncolon_after_super);
+      return true;
+    }
+
+    return Actions.ActOnSuperScopeSpecifier(SuperLoc, ConsumeToken(), SS);
+  }
+
   bool CheckForDestructor = false;
   if (MayBePseudoDestructor && *MayBePseudoDestructor) {
     CheckForDestructor = true;
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index 8514af2a8c8..1020eefb0c4 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -1181,6 +1181,7 @@ Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
       return TPResult::False;
   }
     // Fall through.
+  case tok::kw___super:
   case tok::kw_decltype:
     // Annotate typenames and C++ scope specifiers.  If we get one, just
     // recurse to handle whatever we get.
diff --git a/clang/lib/Parse/Parser.cpp b/clang/lib/Parse/Parser.cpp
index 6dcbaf6bb29..5a0653026f2 100644
--- a/clang/lib/Parse/Parser.cpp
+++ b/clang/lib/Parse/Parser.cpp
@@ -1464,10 +1464,11 @@ bool Parser::TryKeywordIdentFallback(bool DisableKeyword) {
 /// Note that this routine emits an error if you call it with ::new or ::delete
 /// as the current tokens, so only call it in contexts where these are invalid.
 bool Parser::TryAnnotateTypeOrScopeToken(bool EnteringContext, bool NeedType) {
-  assert((Tok.is(tok::identifier) || Tok.is(tok::coloncolon)
-          || Tok.is(tok::kw_typename) || Tok.is(tok::annot_cxxscope)
-          || Tok.is(tok::kw_decltype) || Tok.is(tok::annot_template_id))
-          && "Cannot be a type or scope token!");
+  assert((Tok.is(tok::identifier) || Tok.is(tok::coloncolon) ||
+          Tok.is(tok::kw_typename) || Tok.is(tok::annot_cxxscope) ||
+          Tok.is(tok::kw_decltype) || Tok.is(tok::annot_template_id) ||
+          Tok.is(tok::kw___super)) &&
+         "Cannot be a type or scope token!");
 
   if (Tok.is(tok::kw_typename)) {
     // MSVC lets you do stuff like:
@@ -1676,7 +1677,8 @@ bool Parser::TryAnnotateCXXScopeToken(bool EnteringContext) {
          "Call sites of this function should be guarded by checking for C++");
   assert((Tok.is(tok::identifier) || Tok.is(tok::coloncolon) ||
           (Tok.is(tok::annot_template_id) && NextToken().is(tok::coloncolon)) ||
-         Tok.is(tok::kw_decltype)) && "Cannot be a type or scope token!");
+          Tok.is(tok::kw_decltype) || Tok.is(tok::kw___super)) &&
+         "Cannot be a type or scope token!");
 
   CXXScopeSpec SS;
   if (ParseOptionalCXXScopeSpecifier(SS, ParsedType(), EnteringContext))
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index 17dccc8d22e..50ed49a3b90 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -113,6 +113,18 @@ void CXXScopeSpec::MakeGlobal(ASTContext &Context,
          "NestedNameSpecifierLoc range computation incorrect");
 }
 
+void CXXScopeSpec::MakeSuper(ASTContext &Context, CXXRecordDecl *RD,
+                             SourceLocation SuperLoc,
+                             SourceLocation ColonColonLoc) {
+  Builder.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
+
+  Range.setBegin(SuperLoc);
+  Range.setEnd(ColonColonLoc);
+
+  assert(Range == Builder.getSourceRange() &&
+  "NestedNameSpecifierLoc range computation incorrect");
+}
+
 void CXXScopeSpec::MakeTrivial(ASTContext &Context, 
                                NestedNameSpecifier *Qualifier, SourceRange R) {
   Builder.MakeTrivial(Context, Qualifier, R);
diff --git a/clang/lib/Sema/SemaCXXScopeSpec.cpp b/clang/lib/Sema/SemaCXXScopeSpec.cpp
index d3f0fad3151..739cba72339 100644
--- a/clang/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/clang/lib/Sema/SemaCXXScopeSpec.cpp
@@ -148,6 +148,9 @@ DeclContext *Sema::computeDeclContext(const CXXScopeSpec &SS,
 
   case NestedNameSpecifier::Global:
     return Context.getTranslationUnitDecl();
+
+  case NestedNameSpecifier::Super:
+    return NNS->getAsRecordDecl();
   }
 
   llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
@@ -240,12 +243,43 @@ bool Sema::RequireCompleteDeclContext(CXXScopeSpec &SS,
   return true;
 }
 
-bool Sema::ActOnCXXGlobalScopeSpecifier(Scope *S, SourceLocation CCLoc,
+bool Sema::ActOnCXXGlobalScopeSpecifier(SourceLocation CCLoc,
                                         CXXScopeSpec &SS) {
   SS.MakeGlobal(Context, CCLoc);
   return false;
 }
 
+bool Sema::ActOnSuperScopeSpecifier(SourceLocation SuperLoc,
+                                    SourceLocation ColonColonLoc,
+                                    CXXScopeSpec &SS) {
+  CXXRecordDecl *RD = nullptr;
+  for (Scope *S = getCurScope(); S; S = S->getParent()) {
+    if (S->isFunctionScope()) {
+      if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(S->getEntity()))
+        RD = MD->getParent();
+      break;
+    }
+    if (S->isClassScope()) {
+      RD = cast<CXXRecordDecl>(S->getEntity());
+      break;
+    }
+  }
+
+  if (!RD) {
+    Diag(SuperLoc, diag::err_invalid_super_scope);
+    return true;
+  } else if (RD->isLambda()) {
+    Diag(SuperLoc, diag::err_super_in_lambda_unsupported);
+    return true;
+  } else if (RD->getNumBases() == 0) {
+    Diag(SuperLoc, diag::err_no_base_classes) << RD->getName();
+    return true;
+  }
+
+  SS.MakeSuper(Context, RD, SuperLoc, ColonColonLoc);
+  return false;
+}
+
 /// \brief Determines whether the given declaration is an valid acceptable
 /// result for name lookup of a nested-name-specifier.
 bool Sema::isAcceptableNestedNameSpecifier(const NamedDecl *SD) {
@@ -953,6 +987,7 @@ bool Sema::ShouldEnterDeclaratorScope(Scope *S, const CXXScopeSpec &SS) {
   case NestedNameSpecifier::Identifier:
   case NestedNameSpecifier::TypeSpec:
   case NestedNameSpecifier::TypeSpecWithTemplate:
+  case NestedNameSpecifier::Super:
     // These are never namespace scopes.
     return true;
   }
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 1bac28753fe..abbf4b2bb24 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -498,6 +498,9 @@ DeclSpec::TST Sema::isTagName(IdentifierInfo &II, Scope *S) {
 /// @endcode
 bool Sema::isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S) {
   if (CurContext->isRecord()) {
+    if (SS->getScopeRep()->getKind() == NestedNameSpecifier::Super)
+      return true;
+
     const Type *Ty = SS->getScopeRep()->getAsType();
 
     CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
@@ -699,7 +702,11 @@ Sema::NameClassification Sema::ClassifyName(Scope *S,
   }
 
   LookupResult Result(*this, Name, NameLoc, LookupOrdinaryName);
-  LookupParsedName(Result, S, &SS, !CurMethod);
+  NestedNameSpecifier *NNS = SS.getScopeRep();
+  if (NNS && NNS->getKind() == NestedNameSpecifier::Super)
+    LookupInSuper(Result, NNS->getAsRecordDecl());
+  else
+    LookupParsedName(Result, S, &SS, !CurMethod);
 
   // For unqualified lookup in a class template in MSVC mode, look into
   // dependent base classes where the primary class template is known.
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index f938fd38cdc..d79dcca1e97 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -67,6 +67,7 @@ ParsedType Sema::getInheritingConstructorName(CXXScopeSpec &SS,
     break;
 
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
     llvm_unreachable("Nested name specifier is not a type for inheriting ctor");
@@ -354,6 +355,7 @@ bool Sema::checkLiteralOperatorId(const CXXScopeSpec &SS,
     return true;
 
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
     return false;
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 54f9673e9fa..76e0ba1bcda 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -1824,6 +1824,26 @@ bool Sema::LookupParsedName(LookupResult &R, Scope *S, CXXScopeSpec *SS,
   return LookupName(R, S, AllowBuiltinCreation);
 }
 
+/// \brief Perform qualified name lookup into all base classes of the given
+/// class.
+///
+/// \param R captures both the lookup criteria and any lookup results found.
+///
+/// \param Class The context in which qualified name lookup will
+/// search. Name lookup will search in all base classes merging the results.
+void Sema::LookupInSuper(LookupResult &R, CXXRecordDecl *Class) {
+  for (const auto &BaseSpec : Class->bases()) {
+    CXXRecordDecl *RD = cast<CXXRecordDecl>(
+        BaseSpec.getType()->castAs<RecordType>()->getDecl());
+    LookupResult Result(*this, R.getLookupNameInfo(), R.getLookupKind());
+	Result.setBaseObjectType(Context.getRecordType(Class));
+    LookupQualifiedName(Result, RD);
+    for (auto *Decl : Result)
+      R.addDecl(Decl);
+  }
+
+  R.resolveKind();
+}
 
 /// \brief Produce a diagnostic describing the ambiguity that resulted
 /// from name lookup.
@@ -3296,6 +3316,7 @@ static void getNestedNameSpecifierIdentifiers(
     break;
 
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     return;
   }
 
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 3c37a3e2d06..b47ce684446 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -4127,6 +4127,7 @@ bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
   case NestedNameSpecifier::Namespace:
   case NestedNameSpecifier::NamespaceAlias:
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     return false;
 
   case NestedNameSpecifier::TypeSpec:
@@ -7900,7 +7901,11 @@ Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
 
   DeclarationName Name(&II);
   LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
-  LookupQualifiedName(Result, Ctx);
+  NestedNameSpecifier *NNS = SS.getScopeRep();
+  if (NNS->getKind() == NestedNameSpecifier::Super)
+    LookupInSuper(Result, NNS->getAsRecordDecl());
+  else
+    LookupQualifiedName(Result, Ctx);
   unsigned DiagID = 0;
   Decl *Referenced = nullptr;
   switch (Result.getResultKind()) {
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 51f36feaa46..31d7f73e097 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -3021,6 +3021,7 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
         case NestedNameSpecifier::Namespace:
         case NestedNameSpecifier::NamespaceAlias:
         case NestedNameSpecifier::Global:
+        case NestedNameSpecifier::Super:
           llvm_unreachable("Nested-name-specifier must name a type");
 
         case NestedNameSpecifier::TypeSpec:
@@ -3717,6 +3718,7 @@ namespace {
       case NestedNameSpecifier::Namespace:
       case NestedNameSpecifier::NamespaceAlias:
       case NestedNameSpecifier::Global:
+      case NestedNameSpecifier::Super:
         llvm_unreachable("Nested-name-specifier must name a type");
       }
 
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index af91ea9a00a..687f16473df 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -3100,6 +3100,14 @@ TreeTransform<Derived>::TransformNestedNameSpecifierLoc(
       SS.MakeGlobal(SemaRef.Context, Q.getBeginLoc());
       break;
 
+    case NestedNameSpecifier::Super: {
+      CXXRecordDecl *RD =
+          cast_or_null<CXXRecordDecl>(getDerived().TransformDecl(
+              SourceLocation(), QNNS->getAsRecordDecl()));
+      SS.MakeSuper(SemaRef.Context, RD, Q.getBeginLoc(), Q.getEndLoc());
+      break;
+    }
+
     case NestedNameSpecifier::TypeSpecWithTemplate:
     case NestedNameSpecifier::TypeSpec: {
       TypeLoc TL = TransformTypeInObjectScope(Q.getTypeLoc(), ObjectType,
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 93c01cb1e12..96639f37f0b 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -7927,6 +7927,12 @@ ASTReader::ReadNestedNameSpecifier(ModuleFile &F,
       // No associated value, and there can't be a prefix.
       break;
     }
+
+    case NestedNameSpecifier::Super: {
+      CXXRecordDecl *RD = ReadDeclAs<CXXRecordDecl>(F, Record, Idx);
+      NNS = NestedNameSpecifier::SuperSpecifier(Context, RD);
+      break;
+    }
     }
     Prev = NNS;
   }
@@ -7983,9 +7989,16 @@ ASTReader::ReadNestedNameSpecifierLoc(ModuleFile &F, const RecordData &Record,
       Builder.MakeGlobal(Context, ColonColonLoc);
       break;
     }
+
+    case NestedNameSpecifier::Super: {
+      CXXRecordDecl *RD = ReadDeclAs<CXXRecordDecl>(F, Record, Idx);
+      SourceRange Range = ReadSourceRange(F, Record, Idx);
+      Builder.MakeSuper(Context, RD, Range.getBegin(), Range.getEnd());
+      break;
+    }
     }
   }
-  
+
   return Builder.getWithLocInContext(Context);
 }
 
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 0b65d0a571d..04a39c07aaf 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5245,6 +5245,10 @@ void ASTWriter::AddNestedNameSpecifier(NestedNameSpecifier *NNS,
     case NestedNameSpecifier::Global:
       // Don't need to write an associated value.
       break;
+
+    case NestedNameSpecifier::Super:
+      AddDeclRef(NNS->getAsRecordDecl(), Record);
+      break;
     }
   }
 }
@@ -5294,6 +5298,11 @@ void ASTWriter::AddNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
     case NestedNameSpecifier::Global:
       AddSourceLocation(NNS.getLocalSourceRange().getEnd(), Record);
       break;
+
+    case NestedNameSpecifier::Super:
+      AddDeclRef(NNS.getNestedNameSpecifier()->getAsRecordDecl(), Record);
+      AddSourceRange(NNS.getLocalSourceRange(), Record);
+      break;
     }
   }
 }
diff --git a/clang/tools/libclang/CIndex.cpp b/clang/tools/libclang/CIndex.cpp
index b2a36a394ea..df696b1cdf4 100644
--- a/clang/tools/libclang/CIndex.cpp
+++ b/clang/tools/libclang/CIndex.cpp
@@ -1260,6 +1260,7 @@ bool CursorVisitor::VisitNestedNameSpecifier(NestedNameSpecifier *NNS,
   case NestedNameSpecifier::TypeSpecWithTemplate:
   case NestedNameSpecifier::Global:
   case NestedNameSpecifier::Identifier:
+  case NestedNameSpecifier::Super:
     break;      
   }
   
@@ -1301,6 +1302,7 @@ CursorVisitor::VisitNestedNameSpecifierLoc(NestedNameSpecifierLoc Qualifier) {
         
     case NestedNameSpecifier::Global:
     case NestedNameSpecifier::Identifier:
+    case NestedNameSpecifier::Super:
       break;              
     }
   }
diff --git a/clang/tools/libclang/IndexTypeSourceInfo.cpp b/clang/tools/libclang/IndexTypeSourceInfo.cpp
index f13c0aff0da..706870e514b 100644
--- a/clang/tools/libclang/IndexTypeSourceInfo.cpp
+++ b/clang/tools/libclang/IndexTypeSourceInfo.cpp
@@ -129,6 +129,7 @@ void IndexingContext::indexNestedNameSpecifierLoc(NestedNameSpecifierLoc NNS,
   switch (NNS.getNestedNameSpecifier()->getKind()) {
   case NestedNameSpecifier::Identifier:
   case NestedNameSpecifier::Global:
+  case NestedNameSpecifier::Super:
     break;
 
   case NestedNameSpecifier::Namespace: