add support for FreeBSD's format(printf0,x,y) attribute; allows null format string.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@78276 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/format-attribute-printf0.c b/test/Sema/format-attribute-printf0.c
new file mode 100644
index 0000000..fa7eafd
--- /dev/null
+++ b/test/Sema/format-attribute-printf0.c
@@ -0,0 +1,26 @@
+//RUN: clang-cc -fsyntax-only -verify %s
+
+#include <stdarg.h>
+
+// same as format(printf(...))...
+void a2(const char *a, ...) __attribute__((format(printf0, 1,2))); // no-error
+void b2(const char *a, ...) __attribute__((format(printf0, 1,1))); // expected-error {{'format' attribute parameter 3 is out of bounds}}
+void c2(const char *a, ...) __attribute__((format(printf0, 0,2))); // expected-error {{'format' attribute parameter 2 is out of bounds}}
+void d2(const char *a, int c) __attribute__((format(printf0, 1,2))); // expected-error {{format attribute requires variadic function}}
+void e2(char *str, int c, ...) __attribute__((format(printf0, 2,3))); // expected-error {{format argument not a string type}}
+
+// FreeBSD usage
+#define __printf0like(fmt,va) __attribute__((__format__(__printf0__,fmt,va)))
+void null(int i, const char *a, ...) __printf0like(2,0); // no-error
+void null(int i, const char *a, ...) {
+ if (a)
+ (void)0/* vprintf(...) would go here */;
+}
+
+void callnull(void){
+ null(0, 0); // no error
+ null(0, (char*)0); // no error
+ null(0, (void*)0); // no error
+ null(0, (int*)0); // expected-warning {{incompatible pointer types}}
+}
+