When forming a function call or message send expression, be sure to

strip cv-qualifiers from the expression's type when the language calls
for it: in C, that's all the time, while C++ only does it for
non-class types. 

Centralized the computation of the call expression type in
QualType::getCallResultType() and some helper functions in other nodes
(FunctionDecl, ObjCMethodDecl, FunctionType), and updated all relevant
callers of getResultType() to getCallResultType().

Fixes PR7598 and PR7463, along with a bunch of getResultType() call
sites that weren't stripping references off the result type (nothing
stripped cv-qualifiers properly before this change).

llvm-svn: 108234

12 files changed, 71 insertions, 27 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index cc6ad5ab466..bd97b886fe1 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -576,7 +576,10 @@ QualType CallExpr::getCallReturnType() const {
     CalleeType = FnTypePtr->getPointeeType();
   else if (const BlockPointerType *BPT = CalleeType->getAs<BlockPointerType>())
     CalleeType = BPT->getPointeeType();
-
+  else if (const MemberPointerType *MPT
+                                      = CalleeType->getAs<MemberPointerType>())
+    CalleeType = MPT->getPointeeType();
+    
   const FunctionType *FnType = CalleeType->getAs<FunctionType>();
   return FnType->getResultType();
 }
diff --git a/clang/lib/AST/Type.cpp b/clang/lib/AST/Type.cpp
index 5a7aa89d6df..ab64eafbee2 100644
--- a/clang/lib/AST/Type.cpp
+++ b/clang/lib/AST/Type.cpp
@@ -992,6 +992,22 @@ const char *BuiltinType::getName(const LangOptions &LO) const {
 
 void FunctionType::ANCHOR() {} // Key function for FunctionType.
 
+QualType QualType::getCallResultType(ASTContext &Context) const {
+  if (const ReferenceType *RefType = getTypePtr()->getAs<ReferenceType>())
+    return RefType->getPointeeType();
+  
+  // C++0x [basic.lval]:
+  //   Class prvalues can have cv-qualified types; non-class prvalues always 
+  //   have cv-unqualified types.
+  //
+  // See also C99 6.3.2.1p2.
+  if (!Context.getLangOptions().CPlusPlus ||
+      !getTypePtr()->isDependentType() && !getTypePtr()->isRecordType())
+    return getUnqualifiedType();
+  
+  return *this;
+}
+
 llvm::StringRef FunctionType::getNameForCallConv(CallingConv CC) {
   switch (CC) {
   case CC_Default: llvm_unreachable("no name for default cc");
diff --git a/clang/lib/Rewrite/RewriteObjC.cpp b/clang/lib/Rewrite/RewriteObjC.cpp
index 204ec264156..489fec9be0e 100644
--- a/clang/lib/Rewrite/RewriteObjC.cpp
+++ b/clang/lib/Rewrite/RewriteObjC.cpp
@@ -2113,8 +2113,8 @@ CallExpr *RewriteObjC::SynthesizeCallToFunctionDecl(
   const FunctionType *FT = msgSendType->getAs<FunctionType>();
 
   CallExpr *Exp =  
-    new (Context) CallExpr(*Context, ICE, args, nargs, FT->getResultType(),
-                                EndLoc);
+    new (Context) CallExpr(*Context, ICE, args, nargs, 
+                           FT->getCallResultType(*Context), EndLoc);
   return Exp;
 }
 
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 217ada01c6b..7a39f058c5e 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -561,7 +561,7 @@ Sema::SemaBuiltinAtomicOverloaded(OwningExprResult TheCallResult) {
   TheCall->setCallee(PromotedCall);
 
   // Change the result type of the call to match the result type of the decl.
-  TheCall->setType(NewBuiltinDecl->getResultType());
+  TheCall->setType(NewBuiltinDecl->getCallResultType());
 
   // If the value type was converted to an integer when processing the
   // arguments (e.g. void* -> int), we need to convert the result back.
diff --git a/clang/lib/Sema/SemaCodeComplete.cpp b/clang/lib/Sema/SemaCodeComplete.cpp
index 6a706dfefe5..82861101e83 100644
--- a/clang/lib/Sema/SemaCodeComplete.cpp
+++ b/clang/lib/Sema/SemaCodeComplete.cpp
@@ -567,11 +567,11 @@ static QualType getDeclUsageType(ASTContext &C, NamedDecl *ND) {
   
   QualType T;
   if (FunctionDecl *Function = dyn_cast<FunctionDecl>(ND))
-    T = Function->getResultType();
+    T = Function->getCallResultType();
   else if (ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(ND))
-    T = Method->getResultType();
+    T = Method->getSendResultType();
   else if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(ND))
-    T = FunTmpl->getTemplatedDecl()->getResultType();
+    T = FunTmpl->getTemplatedDecl()->getCallResultType();
   else if (EnumConstantDecl *Enumerator = dyn_cast<EnumConstantDecl>(ND))
     T = C.getTypeDeclType(cast<EnumDecl>(Enumerator->getDeclContext()));
   else if (ObjCPropertyDecl *Property = dyn_cast<ObjCPropertyDecl>(ND))
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 9f9858001e6..ce3bf11caa0 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -3004,7 +3004,7 @@ Sema::LookupMemberExpr(LookupResult &R, Expr *&BaseExpr,
         QualType PType;
 
         if (Getter)
-          PType = Getter->getResultType();
+          PType = Getter->getSendResultType();
         else
           // Get the expression type from Setter's incoming parameter.
           PType = (*(Setter->param_end() -1))->getType();
@@ -3180,7 +3180,7 @@ Sema::LookupMemberExpr(LookupResult &R, Expr *&BaseExpr,
           return ExprError();
 
         return Owned(ObjCMessageExpr::Create(Context,
-                                     OMD->getResultType().getNonReferenceType(),
+                                             OMD->getSendResultType(),
                                              OpLoc, BaseExpr, Sel,
                                              OMD, NULL, 0, MemberLoc));
       }
@@ -3575,7 +3575,7 @@ Sema::ActOnCallExpr(Scope *S, ExprArg fn, SourceLocation LParenLoc,
           BO->getOpcode() == BinaryOperator::PtrMemI) {
         if (const FunctionProtoType *FPT
                                 = BO->getType()->getAs<FunctionProtoType>()) {
-          QualType ResultTy = FPT->getResultType().getNonReferenceType();
+          QualType ResultTy = FPT->getCallResultType(Context);
 
           ExprOwningPtr<CXXMemberCallExpr>
             TheCall(this, new (Context) CXXMemberCallExpr(Context, BO, Args,
@@ -3665,7 +3665,7 @@ Sema::BuildResolvedCallExpr(Expr *Fn, NamedDecl *NDecl,
     return ExprError();
 
   // We know the result type of the call, set it.
-  TheCall->setType(FuncT->getResultType().getNonReferenceType());
+  TheCall->setType(FuncT->getCallResultType(Context));
 
   if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FuncT)) {
     if (ConvertArgumentsForCall(&*TheCall, Fn, FDecl, Proto, Args, NumArgs,
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 180b5911bfc..5c693ab358e 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -3032,7 +3032,7 @@ CXXMemberCallExpr *Sema::BuildCXXMemberCallExpr(Expr *Exp,
   MemberExpr *ME = 
       new (Context) MemberExpr(Exp, /*IsArrow=*/false, Method, 
                                SourceLocation(), Method->getType());
-  QualType ResultType = Method->getResultType().getNonReferenceType();
+  QualType ResultType = Method->getCallResultType();
   MarkDeclarationReferenced(Exp->getLocStart(), Method);
   CXXMemberCallExpr *CE =
     new (Context) CXXMemberCallExpr(Context, ME, 0, 0, ResultType,
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 520ea2af91b..9f43471e0ad 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -207,7 +207,7 @@ bool Sema::CheckMessageArgumentTypes(Expr **Args, unsigned NumArgs,
     return false;
   }
 
-  ReturnType = Method->getResultType().getNonReferenceType();
+  ReturnType = Method->getSendResultType();
 
   unsigned NumNamedArgs = Sel.getNumArgs();
   // Method might have more arguments than selector indicates. This is due
@@ -346,7 +346,7 @@ HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
     Selector Sel = PP.getSelectorTable().getNullarySelector(Member);
     ObjCMethodDecl *Getter = IFace->lookupInstanceMethod(Sel);
     if (DiagnosePropertyAccessorMismatch(PD, Getter, MemberLoc))
-      ResTy = Getter->getResultType();
+      ResTy = Getter->getSendResultType();
     return Owned(new (Context) ObjCPropertyRefExpr(PD, ResTy,
                                                    MemberLoc, BaseExpr));
   }
@@ -402,7 +402,7 @@ HandleExprPropertyRefExpr(const ObjCObjectPointerType *OPT,
 
   if (Getter) {
     QualType PType;
-    PType = Getter->getResultType();
+    PType = Getter->getSendResultType();
     return Owned(new (Context) ObjCImplicitSetterGetterRefExpr(Getter, PType,
                                     Setter, MemberLoc, BaseExpr));
   }
@@ -510,7 +510,7 @@ ActOnClassPropertyRefExpr(IdentifierInfo &receiverName,
     QualType PType;
 
     if (Getter)
-      PType = Getter->getResultType();
+      PType = Getter->getSendResultType();
     else {
       for (ObjCMethodDecl::param_iterator PI = Setter->param_begin(),
            E = Setter->param_end(); PI != E; ++PI)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 5571c1b3824..7536289afc1 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -2942,7 +2942,7 @@ static void TryUserDefinedConversion(Sema &S,
   }
 
   // Add the user-defined conversion step that calls the conversion function.
-  QualType ConvType = Function->getResultType().getNonReferenceType();
+  QualType ConvType = Function->getCallResultType();
   if (ConvType->getAs<RecordType>()) {
     // If we're converting to a class type, there may be an copy if
     // the resulting temporary object (possible to create an object of
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 5b511d7d03c..ee4c479f728 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -6668,7 +6668,7 @@ Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn,
       DiagnoseUseOfDecl(Best->FoundDecl, OpLoc);
 
       // Determine the result type
-      QualType ResultTy = FnDecl->getResultType().getNonReferenceType();
+      QualType ResultTy = FnDecl->getCallResultType();
 
       // Build the actual expression node.
       Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(),
@@ -6875,8 +6875,8 @@ Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
 
         // Determine the result type
         QualType ResultTy
-          = FnDecl->getType()->getAs<FunctionType>()->getResultType();
-        ResultTy = ResultTy.getNonReferenceType();
+          = FnDecl->getType()->getAs<FunctionType>()
+                                                ->getCallResultType(Context);
 
         // Build the actual expression node.
         Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(),
@@ -7032,8 +7032,8 @@ Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
 
         // Determine the result type
         QualType ResultTy
-          = FnDecl->getType()->getAs<FunctionType>()->getResultType();
-        ResultTy = ResultTy.getNonReferenceType();
+          = FnDecl->getType()->getAs<FunctionType>()
+                                                  ->getCallResultType(Context);
 
         // Build the actual expression node.
         Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(),
@@ -7221,7 +7221,7 @@ Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
   ExprOwningPtr<CXXMemberCallExpr>
     TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args,
                                                   NumArgs,
-                                  Method->getResultType().getNonReferenceType(),
+                                  Method->getCallResultType(),
                                   RParenLoc));
 
   // Check for a valid return type.
@@ -7436,7 +7436,7 @@ Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object,
 
   // Once we've built TheCall, all of the expressions are properly
   // owned.
-  QualType ResultTy = Method->getResultType().getNonReferenceType();
+  QualType ResultTy = Method->getCallResultType();
   ExprOwningPtr<CXXOperatorCallExpr>
     TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn,
                                                     MethodArgs, NumArgs + 1,
@@ -7592,7 +7592,7 @@ Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) {
                                            SourceLocation());
   UsualUnaryConversions(FnExpr);
   
-  QualType ResultTy = Method->getResultType().getNonReferenceType();
+  QualType ResultTy = Method->getCallResultType();
   ExprOwningPtr<CXXOperatorCallExpr> 
     TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 
                                                     &Base, 1, ResultTy, OpLoc));
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 48bf7cbac4e..dc3cea1a3c5 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -818,7 +818,7 @@ QualType Sema::BuildFunctionType(QualType T,
       << T->isFunctionType() << T;
     return QualType();
   }
-
+       
   bool Invalid = false;
   for (unsigned Idx = 0; Idx < NumParamTypes; ++Idx) {
     QualType ParamType = adjustParameterType(ParamTypes[Idx]);
@@ -1129,6 +1129,31 @@ TypeSourceInfo *Sema::GetTypeForDeclarator(Declarator &D, Scope *S,
         D.setInvalidType(true);
       }
 
+      // cv-qualifiers on return types are pointless except when the type is a
+      // class type in C++.
+      if (T.getCVRQualifiers() && D.getDeclSpec().getTypeQualifiers() &&
+          (!getLangOptions().CPlusPlus ||
+           (!T->isDependentType() && !T->isRecordType()))) {
+        unsigned Quals = D.getDeclSpec().getTypeQualifiers();
+        SourceLocation Loc;
+        if (Quals & Qualifiers::Const)
+          Loc = D.getDeclSpec().getConstSpecLoc();
+        else if (Quals & Qualifiers::Volatile)
+          Loc = D.getDeclSpec().getVolatileSpecLoc();
+        else {
+          assert((Quals & Qualifiers::Restrict) && "Unknown type qualifier");
+          Loc = D.getDeclSpec().getRestrictSpecLoc();
+        }
+        
+        SemaDiagnosticBuilder DB = Diag(Loc, diag::warn_qual_return_type);
+        if (Quals & Qualifiers::Const)
+          DB << FixItHint::CreateRemoval(D.getDeclSpec().getConstSpecLoc());
+        if (Quals & Qualifiers::Volatile)
+          DB << FixItHint::CreateRemoval(D.getDeclSpec().getVolatileSpecLoc());
+        if (Quals & Qualifiers::Restrict)
+          DB << FixItHint::CreateRemoval(D.getDeclSpec().getRestrictSpecLoc());
+      }
+      
       if (getLangOptions().CPlusPlus && D.getDeclSpec().isTypeSpecOwned()) {
         // C++ [dcl.fct]p6:
         //   Types shall not be defined in return or parameter types.
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index db5e2d10f44..f3ad6c8b4b7 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -1952,7 +1952,7 @@ public:
     Expr **Subs = (Expr **)SubExprs.release();
     CallExpr *TheCall = new (SemaRef.Context) CallExpr(SemaRef.Context, Callee,
                                                        Subs, NumSubExprs,
-                                                       Builtin->getResultType(),
+                                                   Builtin->getCallResultType(),
                                                        RParenLoc);
     OwningExprResult OwnedCall(SemaRef.Owned(TheCall));