Enable C++11 attribute syntax for warn_unused_result and allow it to be

applied to CXXRecordDecls, where functions with that return type will
inherit the warn_unused_result attribute.

Also includes a tiny fix (with no discernable behavior change for
existing code) to re-sync AttributeDeclKind enum and
err_attribute_wrong_decl_type with warn_attribute_wrong_decl_type since
the enum is used with both diagnostic messages to chose the correct
description.

llvm-svn: 167783

2 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 0092d5dab1f..f2e840494fc 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5691,6 +5691,14 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   ProcessDeclAttributes(S, NewFD, D,
                         /*NonInheritable=*/false, /*Inheritable=*/true);
 
+  QualType RetType = NewFD->getResultType();
+  const CXXRecordDecl *Ret = RetType->isRecordType() ?
+      RetType->getAsCXXRecordDecl() : RetType->getPointeeCXXRecordDecl();
+  if (!NewFD->isInvalidDecl() && !NewFD->hasAttr<WarnUnusedResultAttr>() &&
+      Ret && Ret->hasAttr<WarnUnusedResultAttr>()) {
+    NewFD->addAttr(new (Context) WarnUnusedResultAttr(SourceRange(), Context));
+  }
+
   if (!getLangOpts().CPlusPlus) {
     // Perform semantic checking on the function declaration.
     bool isExplicitSpecialization=false;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index e326a20c87d..70bc019a740 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -37,6 +37,7 @@ enum AttributeDeclKind {
   ExpectedFunctionOrMethod,
   ExpectedParameter,
   ExpectedFunctionMethodOrBlock,
+  ExpectedFunctionMethodOrClass,
   ExpectedFunctionMethodOrParameter,
   ExpectedClass,
   ExpectedVariable,
@@ -44,6 +45,7 @@ enum AttributeDeclKind {
   ExpectedVariableFunctionOrLabel,
   ExpectedFieldOrGlobalVar,
   ExpectedStruct,
+  ExpectedVariableFunctionOrTag,
   ExpectedTLSVar
 };
 
@@ -2445,7 +2447,7 @@ static void handleWarnUnusedResult(Sema &S, Decl *D, const AttributeList &Attr)
   if (!checkAttributeNumArgs(S, Attr, 0))
     return;
 
-  if (!isFunction(D) && !isa<ObjCMethodDecl>(D)) {
+  if (!isFunction(D) && !isa<ObjCMethodDecl>(D) && !isa<CXXRecordDecl>(D)) {
     S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
       << Attr.getName() << ExpectedFunctionOrMethod;
     return;