[-fms-extensions] Permit 'override' in C++98 and 'sealed' as a synonym for 'final'

Summary: Some MS headers use these features.

Reviewers: rnk, rsmith

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1948

llvm-svn: 192936

clang/include/clang/Basic/Attr.td

@@ -395,7 +395,8 @@ def FastCall : InheritableAttr {
 }
 
 def Final : InheritableAttr {
-  let Spellings = [];
+  let Spellings = [Keyword<"final">, Keyword<"sealed">];
+  let Accessors = [Accessor<"isSpelledAsSealed", [Keyword<"sealed">]>];
   let SemaHandler = 0;
 }
 

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -704,6 +704,9 @@ def warn_cxx98_compat_override_control_keyword : Warning<
   InGroup<CXX98Compat>, DefaultIgnore;
 def err_override_control_interface : Error<
   "'%0' keyword not permitted with interface types">;
+def ext_ms_sealed_keyword : ExtWarn<
+  "'sealed' keyword is a Microsoft extension">,
+  InGroup<Microsoft>;
 
 def err_access_specifier_interface : Error<
   "interface types cannot specify '%select{private|protected}0' access">;

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1552,16 +1552,16 @@ def override_keyword_hides_virtual_member_function : Error<
 def err_function_marked_override_not_overriding : Error<
   "%0 marked 'override' but does not override any member functions">;
 def err_class_marked_final_used_as_base : Error<
-  "base %0 is marked 'final'">;
+  "base %0 is marked '%select{final|sealed}1'">;
 def warn_abstract_final_class : Warning<
-  "abstract class is marked 'final'">, InGroup<AbstractFinalClass>;
+  "abstract class is marked '%select{final|sealed}0'">, InGroup<AbstractFinalClass>;
 
 // C++11 attributes
 def err_repeat_attribute : Error<"'%0' attribute cannot be repeated">;
 
 // C++11 final
 def err_final_function_overridden : Error<
-  "declaration of %0 overrides a 'final' function">;
+  "declaration of %0 overrides a '%select{final|sealed}1' function">;
 
 // C++11 scoped enumerations
 def err_enum_invalid_underlying : Error<

clang/include/clang/Basic/TokenKinds.def

@@ -350,6 +350,7 @@ KEYWORD(typeof                      , KEYGNU)
 
 // MS Extensions
 KEYWORD(L__FUNCTION__               , KEYMS)
+KEYWORD(__is_sealed                 , KEYMS)
 
 // GNU and MS Type Traits
 KEYWORD(__has_nothrow_assign          , KEYCXX)

clang/include/clang/Basic/TypeTraits.h

@@ -57,6 +57,7 @@ namespace clang {
     UTT_IsReference,
     UTT_IsRvalueReference,
     UTT_IsScalar,
+    UTT_IsSealed,
     UTT_IsSigned,
     UTT_IsStandardLayout,
     UTT_IsTrivial,

clang/include/clang/Parse/Parser.h

@@ -102,6 +102,7 @@ class Parser : public CodeCompletionHandler {
 
   /// Contextual keywords for Microsoft extensions.
   IdentifierInfo *Ident__except;
+  mutable IdentifierInfo *Ident_sealed;
 
   /// Ident_super - IdentifierInfo for "super", to support fast
   /// comparison.

clang/include/clang/Sema/DeclSpec.h

@@ -2107,7 +2107,8 @@ public:
   enum Specifier {
     VS_None = 0,
     VS_Override = 1,
-    VS_Final = 2
+    VS_Final = 2,
+    VS_Sealed = 4
   };
 
   VirtSpecifiers() : Specifiers(0) { }
@@ -2118,7 +2119,8 @@ public:
   bool isOverrideSpecified() const { return Specifiers & VS_Override; }
   SourceLocation getOverrideLoc() const { return VS_overrideLoc; }
 
-  bool isFinalSpecified() const { return Specifiers & VS_Final; }
+  bool isFinalSpecified() const { return Specifiers & (VS_Final | VS_Sealed); }
+  bool isFinalSpelledSealed() const { return Specifiers & VS_Sealed; }
   SourceLocation getFinalLoc() const { return VS_finalLoc; }
 
   void clear() { Specifiers = 0; }

clang/include/clang/Sema/Sema.h

@@ -1725,6 +1725,7 @@ public:
   /// member declarations.
   void ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagDecl,
                                        SourceLocation FinalLoc,
+                                       bool IsFinalSpelledSealed,
                                        SourceLocation LBraceLoc);
 
   /// ActOnTagFinishDefinition - Invoked once we have finished parsing

clang/lib/AST/StmtPrinter.cpp

@@ -1712,6 +1712,7 @@ static const char *getTypeTraitName(UnaryTypeTrait UTT) {
   case UTT_IsReference:             return "__is_reference";
   case UTT_IsRvalueReference:       return "__is_rvalue_reference";
   case UTT_IsScalar:                return "__is_scalar";
+  case UTT_IsSealed:                return "__is_sealed";
   case UTT_IsSigned:                return "__is_signed";
   case UTT_IsStandardLayout:        return "__is_standard_layout";
   case UTT_IsTrivial:               return "__is_trivial";

clang/lib/Lex/PPMacroExpansion.cpp

@@ -983,6 +983,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
            .Case("is_standard_layout", LangOpts.CPlusPlus)
            .Case("is_pod", LangOpts.CPlusPlus)
            .Case("is_polymorphic", LangOpts.CPlusPlus)
+           .Case("is_sealed", LangOpts.MicrosoftExt)
            .Case("is_trivial", LangOpts.CPlusPlus)
            .Case("is_trivially_assignable", LangOpts.CPlusPlus)
            .Case("is_trivially_constructible", LangOpts.CPlusPlus)

clang/lib/Parse/ParseDeclCXX.cpp

@@ -1837,12 +1837,17 @@ VirtSpecifiers::Specifier Parser::isCXX11VirtSpecifier(const Token &Tok) const {
     // Initialize the contextual keywords.
     if (!Ident_final) {
       Ident_final = &PP.getIdentifierTable().get("final");
+      if (getLangOpts().MicrosoftExt)
+        Ident_sealed = &PP.getIdentifierTable().get("sealed");
       Ident_override = &PP.getIdentifierTable().get("override");
     }
 
     if (II == Ident_override)
       return VirtSpecifiers::VS_Override;
 
+    if (II == Ident_sealed)
+      return VirtSpecifiers::VS_Sealed;
+
     if (II == Ident_final)
       return VirtSpecifiers::VS_Final;
   }
@@ -1870,14 +1875,18 @@ void Parser::ParseOptionalCXX11VirtSpecifierSeq(VirtSpecifiers &VS,
         << PrevSpec
         << FixItHint::CreateRemoval(Tok.getLocation());
 
-    if (IsInterface && Specifier == VirtSpecifiers::VS_Final) {
+    if (IsInterface && (Specifier == VirtSpecifiers::VS_Final ||
+                        Specifier == VirtSpecifiers::VS_Sealed)) {
       Diag(Tok.getLocation(), diag::err_override_control_interface)
         << VirtSpecifiers::getSpecifierName(Specifier);
+    } else if (Specifier == VirtSpecifiers::VS_Sealed) {
+      Diag(Tok.getLocation(), diag::ext_ms_sealed_keyword);
     } else {
-      Diag(Tok.getLocation(), getLangOpts().CPlusPlus11 ?
-           diag::warn_cxx98_compat_override_control_keyword :
-           diag::ext_override_control_keyword)
-        << VirtSpecifiers::getSpecifierName(Specifier);
+      Diag(Tok.getLocation(),
+           getLangOpts().CPlusPlus11
+               ? diag::warn_cxx98_compat_override_control_keyword
+               : diag::ext_override_control_keyword)
+          << VirtSpecifiers::getSpecifierName(Specifier);
     }
     ConsumeToken();
   }
@@ -1895,10 +1904,13 @@ bool Parser::isCXX11FinalKeyword() const {
   // Initialize the contextual keywords.
   if (!Ident_final) {
     Ident_final = &PP.getIdentifierTable().get("final");
+    if (getLangOpts().MicrosoftExt)
+      Ident_sealed = &PP.getIdentifierTable().get("sealed");
     Ident_override = &PP.getIdentifierTable().get("override");
   }
-  
-  return Tok.getIdentifierInfo() == Ident_final;
+
+  return Tok.getIdentifierInfo() == Ident_final ||
+         Tok.getIdentifierInfo() == Ident_sealed;
 }
 
 /// ParseCXXClassMemberDeclaration - Parse a C++ class member declaration.
@@ -1929,6 +1941,7 @@ bool Parser::isCXX11FinalKeyword() const {
 ///       virt-specifier:
 ///         override
 ///         final
+/// [MS]    sealed
 /// 
 ///       pure-specifier:
 ///         '= 0'
@@ -2520,20 +2533,27 @@ void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
     Actions.ActOnTagStartDefinition(getCurScope(), TagDecl);
 
   SourceLocation FinalLoc;
+  bool IsFinalSpelledSealed = false;
 
   // Parse the optional 'final' keyword.
   if (getLangOpts().CPlusPlus && Tok.is(tok::identifier)) {
-    assert(isCXX11FinalKeyword() && "not a class definition");
+    VirtSpecifiers::Specifier Specifier = isCXX11VirtSpecifier(Tok);
+    assert((Specifier == VirtSpecifiers::VS_Final ||
+            Specifier == VirtSpecifiers::VS_Sealed) &&
+           "not a class definition");
     FinalLoc = ConsumeToken();
+    IsFinalSpelledSealed = Specifier == VirtSpecifiers::VS_Sealed;
 
-    if (TagType == DeclSpec::TST_interface) {
+    if (TagType == DeclSpec::TST_interface)
       Diag(FinalLoc, diag::err_override_control_interface)
-        << "final";
-    } else {
-      Diag(FinalLoc, getLangOpts().CPlusPlus11 ?
-           diag::warn_cxx98_compat_override_control_keyword :
-           diag::ext_override_control_keyword) << "final";
-    }
+        << VirtSpecifiers::getSpecifierName(Specifier);
+    else if (Specifier == VirtSpecifiers::VS_Final)
+      Diag(FinalLoc, getLangOpts().CPlusPlus11
+                         ? diag::warn_cxx98_compat_override_control_keyword
+                         : diag::ext_override_control_keyword)
+        << VirtSpecifiers::getSpecifierName(Specifier);
+    else if (Specifier == VirtSpecifiers::VS_Sealed)
+      Diag(FinalLoc, diag::ext_ms_sealed_keyword);
 
     // Parse any C++11 attributes after 'final' keyword.
     // These attributes are not allowed to appear here,
@@ -2560,6 +2580,7 @@ void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
 
   if (TagDecl)
     Actions.ActOnStartCXXMemberDeclarations(getCurScope(), TagDecl, FinalLoc,
+                                            IsFinalSpelledSealed,
                                             T.getOpenLocation());
 
   // C++ 11p3: Members of a class defined with the keyword class are private

clang/lib/Parse/ParseExpr.cpp

@@ -591,6 +591,7 @@ class CastExpressionIdValidator : public CorrectionCandidateCallback {
 ///                   '__is_final'
 ///                   '__is_pod'
 ///                   '__is_polymorphic'
+///                   '__is_sealed'                           [MS]
 ///                   '__is_trivial'
 ///                   '__is_union'
 ///
@@ -1200,6 +1201,7 @@ ExprResult Parser::ParseCastExpression(bool isUnaryExpression,
   case tok::kw___is_trivially_copyable:
   case tok::kw___is_union:
   case tok::kw___is_final:
+  case tok::kw___is_sealed:
   case tok::kw___has_trivial_constructor:
   case tok::kw___has_trivial_move_constructor:
   case tok::kw___has_trivial_copy:

clang/lib/Parse/ParseExprCXX.cpp

@@ -2669,6 +2669,7 @@ static UnaryTypeTrait UnaryTypeTraitFromTokKind(tok::TokenKind kind) {
   case tok::kw___is_reference:               return UTT_IsReference;
   case tok::kw___is_rvalue_reference:        return UTT_IsRvalueReference;
   case tok::kw___is_scalar:                  return UTT_IsScalar;
+  case tok::kw___is_sealed:                  return UTT_IsSealed;
   case tok::kw___is_signed:                  return UTT_IsSigned;
   case tok::kw___is_standard_layout:         return UTT_IsStandardLayout;
   case tok::kw___is_trivial:                 return UTT_IsTrivial;

clang/lib/Parse/ParseTentative.cpp

@@ -962,6 +962,7 @@ Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
   case tok::kw___is_literal_type:
   case tok::kw___is_pod:
   case tok::kw___is_polymorphic:
+  case tok::kw___is_sealed:
   case tok::kw___is_trivial:
   case tok::kw___is_trivially_assignable:
   case tok::kw___is_trivially_constructible:

clang/lib/Parse/Parser.cpp

@@ -486,6 +486,7 @@ void Parser::Initialize() {
 
   Ident_instancetype = 0;
   Ident_final = 0;
+  Ident_sealed = 0;
   Ident_override = 0;
 
   Ident_super = &PP.getIdentifierTable().get("super");

clang/lib/Sema/DeclSpec.cpp

@@ -1118,6 +1118,7 @@ bool VirtSpecifiers::SetSpecifier(Specifier VS, SourceLocation Loc,
   switch (VS) {
   default: llvm_unreachable("Unknown specifier!");
   case VS_Override: VS_overrideLoc = Loc; break;
+  case VS_Sealed:
   case VS_Final:    VS_finalLoc = Loc; break;
   }
 
@@ -1129,5 +1130,6 @@ const char *VirtSpecifiers::getSpecifierName(Specifier VS) {
   default: llvm_unreachable("Unknown specifier");
   case VS_Override: return "override";
   case VS_Final: return "final";
+  case VS_Sealed: return "sealed";
   }
 }

clang/lib/Sema/SemaDecl.cpp

@@ -10957,6 +10957,7 @@ Decl *Sema::ActOnObjCContainerStartDefinition(Decl *IDecl) {
 
 void Sema::ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagD,
                                            SourceLocation FinalLoc,
+                                           bool IsFinalSpelledSealed,
                                            SourceLocation LBraceLoc) {
   AdjustDeclIfTemplate(TagD);
   CXXRecordDecl *Record = cast<CXXRecordDecl>(TagD);
@@ -10967,8 +10968,9 @@ void Sema::ActOnStartCXXMemberDeclarations(Scope *S, Decl *TagD,
     return;
 
   if (FinalLoc.isValid())
-    Record->addAttr(new (Context) FinalAttr(FinalLoc, Context));
-    
+    Record->addAttr(new (Context)
+                    FinalAttr(FinalLoc, Context, IsFinalSpelledSealed));
+
   // C++ [class]p2:
   //   [...] The class-name is also inserted into the scope of the
   //   class itself; this is known as the injected-class-name. For

clang/lib/Sema/SemaDeclCXX.cpp

@@ -1373,9 +1373,10 @@ Sema::CheckBaseSpecifier(CXXRecordDecl *Class,
   // C++ [class]p3:
   //   If a class is marked final and it appears as a base-type-specifier in 
   //   base-clause, the program is ill-formed.
-  if (CXXBaseDecl->hasAttr<FinalAttr>()) {
+  if (FinalAttr *FA = CXXBaseDecl->getAttr<FinalAttr>()) {
     Diag(BaseLoc, diag::err_class_marked_final_used_as_base) 
-      << CXXBaseDecl->getDeclName();
+      << CXXBaseDecl->getDeclName()
+      << FA->isSpelledAsSealed();
     Diag(CXXBaseDecl->getLocation(), diag::note_previous_decl)
       << CXXBaseDecl->getDeclName();
     return 0;
@@ -1762,7 +1763,8 @@ void Sema::CheckOverrideControl(NamedDecl *D) {
       } else if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
         Diag(FA->getLocation(),
              diag::override_keyword_hides_virtual_member_function)
-            << "final" << (OverloadedMethods.size() > 1);
+          << (FA->isSpelledAsSealed() ? "sealed" : "final")
+          << (OverloadedMethods.size() > 1);
       }
       NoteHiddenVirtualMethods(MD, OverloadedMethods);
       MD->setInvalidDecl();
@@ -1782,7 +1784,8 @@ void Sema::CheckOverrideControl(NamedDecl *D) {
     if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
       Diag(FA->getLocation(),
            diag::override_keyword_only_allowed_on_virtual_member_functions)
-        << "final" << FixItHint::CreateRemoval(FA->getLocation());
+        << (FA->isSpelledAsSealed() ? "sealed" : "final")
+        << FixItHint::CreateRemoval(FA->getLocation());
       D->dropAttr<FinalAttr>();
     }
     return;
@@ -1804,11 +1807,13 @@ void Sema::CheckOverrideControl(NamedDecl *D) {
 /// C++11 [class.virtual]p4.
 bool Sema::CheckIfOverriddenFunctionIsMarkedFinal(const CXXMethodDecl *New,
                                                   const CXXMethodDecl *Old) {
-  if (!Old->hasAttr<FinalAttr>())
+  FinalAttr *FA = Old->getAttr<FinalAttr>();
+  if (!FA)
     return false;
 
   Diag(New->getLocation(), diag::err_final_function_overridden)
-    << New->getDeclName();
+    << New->getDeclName()
+    << FA->isSpelledAsSealed();
   Diag(Old->getLocation(), diag::note_overridden_virtual_function);
   return true;
 }
@@ -2067,7 +2072,8 @@ Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
   if (VS.isOverrideSpecified())
     Member->addAttr(new (Context) OverrideAttr(VS.getOverrideLoc(), Context));
   if (VS.isFinalSpecified())
-    Member->addAttr(new (Context) FinalAttr(VS.getFinalLoc(), Context));
+    Member->addAttr(new (Context) FinalAttr(VS.getFinalLoc(), Context,
+                                            VS.isFinalSpelledSealed()));
 
   if (VS.getLastLocation().isValid()) {
     // Update the end location of a method that has a virt-specifiers.
@@ -4406,9 +4412,12 @@ void Sema::CheckCompletedCXXClass(CXXRecordDecl *Record) {
            diag::warn_non_virtual_dtor) << Context.getRecordType(Record);
   }
 
-  if (Record->isAbstract() && Record->hasAttr<FinalAttr>()) {
-    Diag(Record->getLocation(), diag::warn_abstract_final_class);
-    DiagnoseAbstractType(Record);
+  if (Record->isAbstract()) {
+    if (FinalAttr *FA = Record->getAttr<FinalAttr>()) {
+      Diag(Record->getLocation(), diag::warn_abstract_final_class)
+        << FA->isSpelledAsSealed();
+      DiagnoseAbstractType(Record);
+    }
   }
 
   if (!Record->isDependentType()) {

clang/lib/Sema/SemaExprCXX.cpp

@@ -3131,6 +3131,7 @@ static bool CheckUnaryTypeTraitTypeCompleteness(Sema &S,
 
   // These traits require a complete type.
   case UTT_IsFinal:
+  case UTT_IsSealed:
 
     // These trait expressions are designed to help implement predicates in
     // [meta.unary.prop] despite not being named the same. They are specified
@@ -3304,6 +3305,11 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, UnaryTypeTrait UTT,
     if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
       return RD->hasAttr<FinalAttr>();
     return false;
+  case UTT_IsSealed:
+    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
+      if (FinalAttr *FA = RD->getAttr<FinalAttr>())
+        return FA->isSpelledAsSealed();
+    return false;
   case UTT_IsSigned:
     return T->isSignedIntegerType();
   case UTT_IsUnsigned:

clang/test/SemaCXX/MicrosoftExtensions.cpp

@@ -385,3 +385,28 @@ namespace rdar14250378 {
     }
   }
 }
+
+// expected-error@+1 {{'sealed' keyword not permitted with interface types}}
+__interface InterfaceWithSealed sealed {
+};
+
+struct SomeBase {
+  virtual void OverrideMe();
+
+  // expected-note@+2 {{overridden virtual function is here}}
+  // expected-warning@+1 {{'sealed' keyword is a Microsoft extension}}
+  virtual void SealedFunction() sealed;
+};
+
+// expected-note@+2 {{'SealedType' declared here}}
+// expected-warning@+1 {{'sealed' keyword is a Microsoft extension}}
+struct SealedType sealed : SomeBase {
+  // expected-error@+1 {{declaration of 'SealedFunction' overrides a 'sealed' function}}
+  virtual void SealedFunction();
+
+  // expected-warning@+1 {{'override' keyword is a C++11 extension}}
+  virtual void OverrideMe() override;
+};
+
+// expected-error@+1 {{base 'SealedType' is marked 'sealed'}}
+struct InheritFromSealed : SealedType {};

clang/test/SemaCXX/type-traits.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fsyntax-only -verify -std=gnu++11 %s 
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fsyntax-only -verify -std=gnu++11 -fms-extensions -Wno-microsoft %s
 #define T(b) (b) ? 1 : -1
 #define F(b) (b) ? -1 : 1
 
@@ -308,6 +308,37 @@ void is_final()
 	{ int arr[F(__is_final(PotentiallyFinal<float>))]; }
 }
 
+struct SealedClass sealed {
+};
+
+template<typename T>
+struct PotentiallySealed { };
+
+template<typename T>
+struct PotentiallySealed<T*> sealed { };
+
+template<>
+struct PotentiallySealed<int> sealed { };
+
+void is_sealed()
+{
+	{ int arr[T(__is_sealed(SealedClass))]; }
+	{ int arr[T(__is_sealed(PotentiallySealed<float*>))]; }
+	{ int arr[T(__is_sealed(PotentiallySealed<int>))]; }
+
+	{ int arr[F(__is_sealed(int))]; }
+	{ int arr[F(__is_sealed(Union))]; }
+	{ int arr[F(__is_sealed(Int))]; }
+	{ int arr[F(__is_sealed(IntAr))]; }
+	{ int arr[F(__is_sealed(UnionAr))]; }
+	{ int arr[F(__is_sealed(Derives))]; }
+	{ int arr[F(__is_sealed(ClassType))]; }
+	{ int arr[F(__is_sealed(cvoid))]; }
+	{ int arr[F(__is_sealed(IntArNB))]; }
+	{ int arr[F(__is_sealed(HasAnonymousUnion))]; }
+	{ int arr[F(__is_sealed(PotentiallyFinal<float>))]; }
+}
+
 typedef HasVirt Polymorph;
 struct InheritPolymorph : Polymorph {};