Disable -Wformat-overflow= warnings for some printf tests.

Recent GCC -Wformat-overflow= changes result in some printf tests
failing to build, because those tests are deliberately testing the
handling of formats writing more than INT_MAX characters and the
handling of NULL arguments to the %s format, which GCC now warns
about.  This patch duly disables -Wformat-overflow= for the relevant
calls to printf functions.

Tested with build-many-glibcs.py with GCC mainline for
aarch64-linux-gnu.

	* stdio-common/bug22.c: Include <libc-diag.h>.
	(do_test): Disable -Wformat-overflow= warnings around fprintf
	calls outputting more than INT_MAX characters.
	* stdio-common/tst-printf.c: Disable -Wformat-overflow= warnings
	around printf call with NULL %s argument.

diff --git a/ChangeLog b/ChangeLog
index 96f6ce52d888759515deccc72b3a736a47946b7e..0c6b43ebc0619a1080d49b8dbd0c804594c8947e 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2018-11-01  Joseph Myers  <joseph@codesourcery.com>
 
+       * stdio-common/bug22.c: Include <libc-diag.h>.
+       (do_test): Disable -Wformat-overflow= warnings around fprintf
+       calls outputting more than INT_MAX characters.
+       * stdio-common/tst-printf.c: Disable -Wformat-overflow= warnings
+       around printf call with NULL %s argument.
+
        [BZ #23848]
        * sysdeps/unix/sysv/linux/sparc/kernel-features.h [!__arch64__ &&
        __LINUX_KERNEL_VERSION < 0x040400] (__ASSUME_SENDMSG_SYSCALL):

diff --git a/stdio-common/bug22.c b/stdio-common/bug22.c
index b26399acb7dfc775887b366692050f6e478d5e1f..b3d48eb8e121cca1849cdbe8acd47838e695c47b 100644 (file)
--- a/stdio-common/bug22.c
+++ b/stdio-common/bug22.c
@@ -1,6 +1,7 @@
 /* BZ #5424 */
 #include <stdio.h>
 #include <errno.h>
+#include <libc-diag.h>
 
 /* INT_MAX + 1 */
 #define N 2147483648
@@ -30,12 +31,26 @@ do_test (void)
       return 1;
     }
 
+  /* GCC 9 warns about output of more than INT_MAX characters; this is
+     deliberately tested here.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+  DIAG_IGNORE_NEEDS_COMMENT (9, "-Wformat-overflow=");
+#endif
   ret = fprintf (fp, "%" SN "d", 1);
+  DIAG_POP_NEEDS_COMMENT;
   printf ("ret = %d\n", ret);
   if (ret != -1 || errno != EOVERFLOW)
          return 1;
 
+  /* GCC 9 warns about output of more than INT_MAX characters; this is
+     deliberately tested here.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+  DIAG_IGNORE_NEEDS_COMMENT (9, "-Wformat-overflow=");
+#endif
   ret = fprintf (fp, "%." SN "d", 1);
+  DIAG_POP_NEEDS_COMMENT;
   printf ("ret = %d\n", ret);
   if (ret != -1 || errno != EOVERFLOW)
          return 1;
@@ -45,7 +60,14 @@ do_test (void)
   if (ret != -1 || errno != EOVERFLOW)
          return 1;
 
+  /* GCC 9 warns about output of more than INT_MAX characters; this is
+     deliberately tested here.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+  DIAG_IGNORE_NEEDS_COMMENT (9, "-Wformat-overflow=");
+#endif
   ret = fprintf (fp, "%" SN2 "d%" SN2 "d", 1, 1);
+  DIAG_POP_NEEDS_COMMENT;
   printf ("ret = %d\n", ret);
 
   return ret != -1 || errno != EOVERFLOW;

diff --git a/stdio-common/tst-printf.c b/stdio-common/tst-printf.c
index 70d9e584b3d3c3ca9cc4782cd5785bdf827344d1..e4f4f1624ddbf3321678a5502a6a84155951255b 100644 (file)
--- a/stdio-common/tst-printf.c
+++ b/stdio-common/tst-printf.c
@@ -110,7 +110,14 @@ I am ready for my first lesson today.";
   printf("left-adjusted Z string:\t\"%-010s\"\n", shortstr);
   printf("space-padded string:\t\"%10s\"\n", shortstr);
   printf("left-adjusted S string:\t\"%-10s\"\n", shortstr);
+  /* GCC 9 warns about the NULL format argument; this is deliberately
+     tested here.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+#if __GNUC_PREREQ (7, 0)
+  DIAG_IGNORE_NEEDS_COMMENT (9, "-Wformat-overflow=");
+#endif
   printf("null string:\t\"%s\"\n", (char *)NULL);
+  DIAG_POP_NEEDS_COMMENT;
   printf("limited string:\t\"%.22s\"\n", longstr);
 
   printf("a-style max:\t\"%a\"\n", DBL_MAX);