Diagnose declspecs occuring after virt-specifier-seq and generate fixit hints

Summary: This fixes PR22075.

Reviewers: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D6828

llvm-svn: 233160

7 files changed, 75 insertions, 3 deletions

diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 56a984baf4c..d96fbac50d3 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -183,6 +183,8 @@ def warn_attribute_no_decl : Warning<
   "attribute %0 ignored, because it is not attached to a declaration">, 
   InGroup<IgnoredAttributes>;
 def err_expected_method_body : Error<"expected method body">;
+def err_declspec_after_virtspec : Error<
+  "'%0' qualifier may not appear after the virtual specifier '%1'">;
 def err_invalid_token_after_toplevel_declarator : Error<
   "expected ';' after top level declarator">;
 def err_invalid_token_after_declarator_suggest_equal : Error<
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 498af7c5b7c..ba3fd133cc6 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -2293,6 +2293,8 @@ private:
                                                  VirtSpecifiers &VS,
                                                  ExprResult &BitfieldSize,
                                                  LateParsedAttrList &LateAttrs);
+  void MaybeParseAndDiagnoseDeclSpecAfterCXX11VirtSpecifierSeq(Declarator &D,
+                                                               VirtSpecifiers &VS);
   void ParseCXXClassMemberDeclaration(AccessSpecifier AS, AttributeList *Attr,
                   const ParsedTemplateInfo &TemplateInfo = ParsedTemplateInfo(),
                   ParsingDeclRAIIObject *DiagsFromTParams = nullptr);
diff --git a/clang/include/clang/Sema/DeclSpec.h b/clang/include/clang/Sema/DeclSpec.h
index 76ccb1d23a8..03c3427d68b 100644
--- a/clang/include/clang/Sema/DeclSpec.h
+++ b/clang/include/clang/Sema/DeclSpec.h
@@ -2180,7 +2180,7 @@ public:
     VS_Sealed = 4
   };
 
-  VirtSpecifiers() : Specifiers(0) { }
+  VirtSpecifiers() : Specifiers(0), LastSpecifier(VS_None) { }
 
   bool SetSpecifier(Specifier VS, SourceLocation Loc,
                     const char *&PrevSpec);
@@ -2198,12 +2198,16 @@ public:
 
   static const char *getSpecifierName(Specifier VS);
 
+  SourceLocation getFirstLocation() const { return FirstLocation; }
   SourceLocation getLastLocation() const { return LastLocation; }
+  Specifier getLastSpecifier() const { return LastSpecifier; }
   
 private:
   unsigned Specifiers;
+  Specifier LastSpecifier;
 
   SourceLocation VS_overrideLoc, VS_finalLoc;
+  SourceLocation FirstLocation;
   SourceLocation LastLocation;
 };
 
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index b4a76642981..c19759e596c 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -5329,7 +5329,7 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
     if (getLangOpts().CPlusPlus) {
       // FIXME: Accept these components in any order, and produce fixits to
       // correct the order if the user gets it wrong. Ideally we should deal
-      // with the virt-specifier-seq and pure-specifier in the same way.
+      // with the pure-specifier in the same way.
 
       // Parse cv-qualifier-seq[opt].
       ParseTypeQualifierListOpt(DS, AR_NoAttributesParsed,
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 3403cdea7ae..aac7d630954 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -2037,10 +2037,13 @@ bool Parser::ParseCXXMemberDeclaratorBeforeInitializer(
     BitfieldSize = ParseConstantExpression();
     if (BitfieldSize.isInvalid())
       SkipUntil(tok::comma, StopAtSemi | StopBeforeMatch);
-  } else
+  } else {
     ParseOptionalCXX11VirtSpecifierSeq(
         VS, getCurrentClass().IsInterface,
         DeclaratorInfo.getDeclSpec().getFriendSpecLoc());
+    if (!VS.isUnset())
+      MaybeParseAndDiagnoseDeclSpecAfterCXX11VirtSpecifierSeq(DeclaratorInfo, VS);
+  }
 
   // If a simple-asm-expr is present, parse it.
   if (Tok.is(tok::kw_asm)) {
@@ -2071,6 +2074,7 @@ bool Parser::ParseCXXMemberDeclaratorBeforeInitializer(
           Diag(Attr->getLoc(), diag::warn_gcc_attribute_location);
         Attr = Attr->getNext();
       }
+      MaybeParseAndDiagnoseDeclSpecAfterCXX11VirtSpecifierSeq(DeclaratorInfo, VS);
     }
   }
 
@@ -2084,6 +2088,52 @@ bool Parser::ParseCXXMemberDeclaratorBeforeInitializer(
   return false;
 }
 
+/// \brief Look for declaration specifiers possibly occurring after C++11
+/// virt-specifier-seq and diagnose them.
+void Parser::MaybeParseAndDiagnoseDeclSpecAfterCXX11VirtSpecifierSeq(
+    Declarator &D,
+    VirtSpecifiers &VS) {
+  DeclSpec DS(AttrFactory);
+
+  // GNU-style and C++11 attributes are not allowed here, but they will be
+  // handled by the caller.  Diagnose everything else.
+  ParseTypeQualifierListOpt(DS, AR_NoAttributesParsed, false);
+  D.ExtendWithDeclSpec(DS);
+
+  if (D.isFunctionDeclarator()) {
+    if (DS.getTypeQualifiers() != DeclSpec::TQ_unspecified) {
+      auto DeclSpecCheck = [&] (DeclSpec::TQ TypeQual,
+                                const char *FixItName,
+                                SourceLocation SpecLoc,
+                                unsigned* QualifierLoc) {
+        FixItHint Insertion;
+        auto &Function = D.getFunctionTypeInfo();
+        if (DS.getTypeQualifiers() & TypeQual) {
+          if (!(Function.TypeQuals & TypeQual)) {
+            std::string Name(FixItName);
+            Name += " ";
+            Insertion = FixItHint::CreateInsertion(VS.getFirstLocation(), Name.c_str());
+            Function.TypeQuals |= TypeQual;
+            *QualifierLoc = SpecLoc.getRawEncoding();
+          }
+          Diag(SpecLoc, diag::err_declspec_after_virtspec)
+            << FixItName
+            << VirtSpecifiers::getSpecifierName(VS.getLastSpecifier())
+            << FixItHint::CreateRemoval(SpecLoc)
+            << Insertion;
+        }
+      };
+      auto &Function = D.getFunctionTypeInfo();
+      DeclSpecCheck(DeclSpec::TQ_const, "const", DS.getConstSpecLoc(),
+                    &Function.ConstQualifierLoc);
+      DeclSpecCheck(DeclSpec::TQ_volatile, "volatile", DS.getVolatileSpecLoc(),
+                    &Function.VolatileQualifierLoc);
+      DeclSpecCheck(DeclSpec::TQ_restrict, "restrict", DS.getRestrictSpecLoc(),
+                    &Function.RestrictQualifierLoc);
+    }
+  }
+}
+
 /// ParseCXXClassMemberDeclaration - Parse a C++ class member declaration.
 ///
 ///       member-declaration:
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index 5e349bc2ad2..f6689a96bdc 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -1220,7 +1220,10 @@ void UnqualifiedId::setOperatorFunctionId(SourceLocation OperatorLoc,
 
 bool VirtSpecifiers::SetSpecifier(Specifier VS, SourceLocation Loc,
                                   const char *&PrevSpec) {
+  if (!FirstLocation.isValid())
+    FirstLocation = Loc;
   LastLocation = Loc;
+  LastSpecifier = VS;
   
   if (Specifiers & VS) {
     PrevSpec = getSpecifierName(VS);
diff --git a/clang/test/FixIt/fixit-cxx0x.cpp b/clang/test/FixIt/fixit-cxx0x.cpp
index 49a05ff8d1e..6e096e5e78e 100644
--- a/clang/test/FixIt/fixit-cxx0x.cpp
+++ b/clang/test/FixIt/fixit-cxx0x.cpp
@@ -158,3 +158,14 @@ namespace MisplacedParameterPack {
   template <int... N...> // expected-error {{'...' must immediately precede declared identifier}}
   void redundantEllipsisInNonTypeTemplateParameter();
 }
+
+namespace MisplacedDeclSpecAfterVirtSpec {
+  struct B {
+    virtual void f();
+    virtual void f() volatile const;
+  };
+  struct D : B {
+    virtual void f() override;
+    virtual void f() override final const volatile; // expected-error {{'const' qualifier may not appear after the virtual specifier 'final'}} expected-error {{'volatile' qualifier may not appear after the virtual specifier 'final'}}
+  };
+}