add support for FreeBSD's format(printf0,x,y) attribute; allows null format string.

llvm-svn: 78276

1 files changed, 26 insertions, 0 deletions

diff --git a/clang/test/Sema/format-attribute-printf0.c b/clang/test/Sema/format-attribute-printf0.c
new file mode 100644
index 00000000000..fa7eafd52fb
--- /dev/null
+++ b/clang/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}}
+}
+