c/objc: problem originally reported as an objective-c bug.

But it is in the underlying c part of clang. clang crashes
in IRGen when passing an incomplete type argument to 
variadic function (instead of diagnosing the bug).
// rdar://10961370


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151862 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 18 insertions, 0 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 149201192f..6deffa2abd 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -587,6 +587,12 @@ ExprResult Sema::DefaultVariadicArgumentPromotion(Expr *E, VariadicCallType CT,
       E = Comma.get();
     }
   }
+  // c++ rules are enfroced elsewhere.
+  if (!getLangOptions().CPlusPlus &&
+      !E->getType()->isVoidType() &&
+      RequireCompleteType(E->getExprLoc(), E->getType(),
+                          diag::err_incomplete_type))
+    return ExprError();
   
   return Owned(E);
 }
diff --git a/test/Sema/variadic-incomplete-arg-type.c b/test/Sema/variadic-incomplete-arg-type.c
new file mode 100644
index 0000000000..1306173a0e
--- /dev/null
+++ b/test/Sema/variadic-incomplete-arg-type.c
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 %s -fsyntax-only -verify 
+// rdar://10961370
+
+typedef struct __CFError * CFErrorRef; // expected-note {{forward declaration of 'struct __CFError'}}
+
+void junk(int, ...);
+
+int main()
+{
+ CFErrorRef error;
+ junk(1, *error); // expected-error {{incomplete type 'struct __CFError' where a complete type is required}}
+}