Index: include/clang/Sema/AttributeList.h
===================================================================
--- include/clang/Sema/AttributeList.h
+++ include/clang/Sema/AttributeList.h
@@ -140,6 +140,12 @@
   virtual bool existsInTarget(const TargetInfo &Target) const {
     return true;
   }
+  /// If this ParsedAttrInfo knows how to apply an attribute to a decl then do
+  /// so and return true. If not return false.
+  virtual bool handleDeclAttribute(Sema &S, Decl *D,
+                                   const AttributeList &Attr) {
+    return false;
+  }
 };
 
 /// AttributeList - Represents a syntactic attribute.
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp
+++ lib/Sema/SemaDeclAttr.cpp
@@ -5752,6 +5752,9 @@
   if (handleCommonAttributeFeatures(S, scope, D, Attr))
     return;
 
+  if (Attr.getInfo()->handleDeclAttribute(S, D, Attr))
+    return;
+
   switch (Attr.getKind()) {
   default:
     if (!Attr.isStmtAttr()) {