Warn about non-standard format strings (pr12017)

This adds the -Wformat-non-standard flag (off by default,
enabled by -pedantic), which warns about non-standard
things in format strings (such as the 'q' length modifier,
the 'S' conversion specifier, etc.)

llvm-svn: 151154

1 files changed, 9 insertions, 6 deletions

diff --git a/clang/test/Sema/format-strings-c90.c b/clang/test/Sema/format-strings-c90.c
index 0b32e82d872..63d58532cb8 100644
--- a/clang/test/Sema/format-strings-c90.c
+++ b/clang/test/Sema/format-strings-c90.c
@@ -5,9 +5,8 @@ int scanf(const char * restrict, ...);
 int printf(const char *restrict, ...);
 
 void foo(char **sp, float *fp, int *ip) {
-  /* TODO: Warn that the 'a' length modifier is an extension. */
-  scanf("%as", sp);
-  scanf("%a[abc]", sp);
+  scanf("%as", sp); /* expected-warning{{'a' is a non-standard length modifier}} */
+  scanf("%a[abc]", sp); /* expected-warning{{'a' is a non-standard length modifier}} */
 
   /* TODO: Warn that the 'a' conversion specifier is a C99 feature. */
   scanf("%a", fp);
@@ -21,7 +20,11 @@ void foo(char **sp, float *fp, int *ip) {
   scanf("%da", ip);
 
   /* Test argument type check for the 'a' length modifier. */
-  scanf("%as", fp); /* expected-warning{{format specifies type 'char **' but the argument has type 'float *'}} */
-  scanf("%aS", fp); /* expected-warning{{format specifies type 'wchar_t **' (aka 'int **') but the argument has type 'float *'}} */
-  scanf("%a[abc]", fp); /* expected-warning{{format specifies type 'char **' but the argument has type 'float *'}} */
+  scanf("%as", fp); /* expected-warning{{format specifies type 'char **' but the argument has type 'float *'}}
+                       expected-warning{{'a' is a non-standard length modifier}} */
+  scanf("%aS", fp); /* expected-warning{{format specifies type 'wchar_t **' (aka 'int **') but the argument has type 'float *'}}
+                       expected-warning{{'a' is a non-standard length modifier}}
+                       expected-warning{{'S' is a non-standard conversion specifier}} */
+  scanf("%a[abc]", fp); /* expected-warning{{format specifies type 'char **' but the argument has type 'float *'}}
+                           expected-warning{{'a' is a non-standard length modifier}} */
 }