Minor refactoring of sentinel warning on blocks.  Add a test for this warning.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147641 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 0b8e9fa..cdba620 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1878,10 +1878,11 @@
       S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_not_variadic) << 0;
       return;
     }
-  } else if (isa<BlockDecl>(D)) {
-    // Note! BlockDecl is typeless. Variadic diagnostics will be issued by the
-    // caller.
-    ;
+  } else if (BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
+    if (!BD->isVariadic()) {
+      S.Diag(Attr.getLoc(), diag::warn_attribute_sentinel_not_variadic) << 1;
+      return;
+    }
   } else if (const VarDecl *V = dyn_cast<VarDecl>(D)) {
     QualType Ty = V->getType();
     if (Ty->isBlockPointerType() || Ty->isFunctionPointerType()) {