Separate NUL byte detection from rest of -Wformat warnings

From-SVN: r123640

gcc/ChangeLog

+2007-04-07  Bruce Korb  <bkorb@gnu.org>
+
+	* c.opt: Add -Wformat-contains-nul.
+	* c-format.c (set_Wformat):  Set warn_format_contains_nul to the
+	  -Wformat setting.
+	(check_format_info_main): Check OPT_Wformat_contains_nul before emitting
+	the NUL byte warning.
+
 2007-04-07  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/i386/i386.c (ix86_handle_option): Handle SSSE3.

gcc/c-format.c

@@ -40,6 +40,7 @@ set_Wformat (int setting)
   warn_format = setting;
   warn_format_extra_args = setting;
   warn_format_zero_length = setting;
+  warn_format_contains_nul = setting;
   if (setting != 1)
     {
       warn_format_nonliteral = setting;
@@ -1482,7 +1483,7 @@ check_format_info_main (format_check_results *res,
       if (*format_chars == 0)
 	{
 	  if (format_chars - orig_format_chars != format_length)
-	    warning (OPT_Wformat, "embedded %<\\0%> in format");
+	    warning (OPT_Wformat_contains_nul, "embedded %<\\0%> in format");
 	  if (info->first_arg_num != 0 && params != 0
 	      && has_operand_number <= 0)
 	    {

gcc/c-opts.c

@@ -1106,6 +1106,8 @@ c_common_post_options (const char **pfilename)
 	       "-Wformat-zero-length ignored without -Wformat");
       warning (OPT_Wformat_nonliteral,
 	       "-Wformat-nonliteral ignored without -Wformat");
+      warning (OPT_Wformat_contains_nul,
+	       "-Wformat-contains-nul ignored without -Wformat");
       warning (OPT_Wformat_security,
 	       "-Wformat-security ignored without -Wformat");
     }

gcc/c.opt

@@ -216,6 +216,10 @@ Wformat-nonliteral
 C ObjC C++ ObjC++ Var(warn_format_nonliteral) Warning
 Warn about format strings that are not literals
 
+Wformat-contains-nul
+C ObjC C++ ObjC++ Var(warn_format_contains_nul)
+Warn about format strings that contain NUL bytes
+
 Wformat-security
 C ObjC C++ ObjC++ Var(warn_format_security) Warning
 Warn about possible security problems with format functions

gcc/testsuite/ChangeLog

+2007-04-07  Bruce Korb  <bkorb@gnu.org>
+
+	* gcc.dg/format/opt-6.c: New test.
+	* gcc.dg/format/nul-1.c: New test.
+	* gcc.dg/format/nul-2.c: New test.
+
 2007-04-06  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/31395

gcc/testsuite/gcc.dg/format/nul-1.c

+/* Test diagnostics for suppressing contains nul
+   -Wformat.  -Wformat.  */
+/* Origin: Bruce Korb <bkorb@gnu.org> */
+/* { dg-do compile } */
+/* { dg-options "-Wformat -Wno-format-contains-nul" } */
+
+#include "format.h"
+
+void
+foo (void)
+{
+  static char const fmt[] = "x%s\0%s\n\0abc";
+  printf (fmt+4, fmt+8); /* { dg-bogus "embedded.*in format" "bogus embed warning" } */
+}

gcc/testsuite/gcc.dg/format/nul-2.c

+/* Test diagnostics for options used on their own without
+   -Wformat.  -Wformat-.  */
+/* Origin: Bruce Korb <bkorb@gnu.org> */
+/* { dg-do compile } */
+/* { dg-options "-Wformat" } */
+
+/* { dg-warning "warning: embedded .* in format" "ignored" { target *-*-* } 0 } */
+
+#include "format.h"
+
+void
+fumble (void)
+{
+  static char const fmt[] = "x%s\0%s\n\0abc";
+  printf (fmt+4, fmt+8);
+}

gcc/testsuite/gcc.dg/format/opt-6.c

+/* Test diagnostics for options used on their own without
+   -Wformat.  -Wformat-contains-nul.  */
+/* Origin: Bruce Korb <bkorb@gnu.org> */
+/* { dg-do compile } */
+/* { dg-options "-Wformat-contains-nul" } */
+
+/* { dg-warning "warning: -Wformat-contains-nul ignored without -Wformat" "ignored" { target *-*-* } 0 } */