Index: include/clang/Basic/Attr.td
===================================================================
--- include/clang/Basic/Attr.td
+++ include/clang/Basic/Attr.td
@@ -1704,6 +1704,11 @@
   let Documentation = [PcsDocs];
 }
 
+def WriteOnlyFunc : InheritableAttr {
+  let Spellings = [Clang<"writeOnlyFunc">];
+  let Documentation = [Undocumented];
+}
+
 def Pure : InheritableAttr {
   let Spellings = [GCC<"pure">];
   let Documentation = [Undocumented];