Re: Silence compiler warning on

[Daniel Jacobowitz <drow@false.org>]

On Tue, Apr 18, 2006 at 11:12:57AM +0200, Mark Kettenis wrote:
> Right now, when I compile BFD on HP-UX 10.20, I get the following
> warning (wich is fatal because of -Werror):
> 
> /export/jive/kettenis/src/gdb/bfd/bfd.c: In function `_bfd_abort':
> /export/jive/kettenis/src/gdb/bfd/bfd.c:801: warning: `noreturn' function does return
> 
> The problem here is that the system headers don't declare _exit() with
> __attribute__((noreturn).  Previously we didn't get this warning
> because _bfd_abort() called xexit(), which was declared with
> __attribute__((noreturn)) (and xexit.c was compiled without -Werror).
> 
> The attached patch is an attempt to fix this.  Ok?
> 
> 
> Index: ChangeLog
> from  Mark Kettenis  <kettenis@jive.nl>
> 
>         * bfd.c (_bfd_abort): Provide prototype for _exit with
>         ATTRIBUTE_NORETURN.

I would like this fixed before binutils 2.17.  Does something like this
work for you?

-- 
Daniel Jacobowitz
CodeSourcery

2006-05-04  Daniel Jacobiwtz  <dan@codesourcery.com>

	* configure.in: Check if _exit with ATTRIBUTE_NORETURN is OK.
	* bfd.c (_bfd_abort): Handle USE_EXIT_NORETURN.
	* configure, config.in: Regenerated.

Index: configure.in
===================================================================
RCS file: /cvs/src/src/bfd/configure.in,v
retrieving revision 1.206
diff -u -p -r1.206 configure.in
--- configure.in	16 Apr 2006 18:01:02 -0000	1.206
+++ configure.in	4 May 2006 18:37:57 -0000
@@ -159,6 +159,19 @@ AC_CHECK_DECLS(strstr)
 AC_CHECK_DECLS(snprintf)
 AC_CHECK_DECLS(vsnprintf)
 
+# At least HP-UX 10.20 declares _exit without noreturn.  If we can
+# add the attribute ourselves, we'll do so.
+AC_CACHE_CHECK([if we can redeclare _exit], bfd_cv_exit_noreturn,
+[AC_COMPILE_IFELSE(
+  [AC_LANG_PROGRAM([#include "../include/ansidecl.h"],
+		   [[extern void _exit (int) ATTRIBUTE_NORETURN; _exit (0);]])],
+  [bfd_cv_exit_noreturn=yes],
+  [bfd_cv_exit_noreturn=no])])
+if test "$bfd_cv_exit_noreturn" = yes; then
+  AC_DEFINE(USE_EXIT_NORETURN, 1,
+    [Define if redeclaring _exit with noreturn is OK])
+fi
+
 # If we are configured native, pick a core file support file.
 COREFILE=
 COREFLAG=
Index: bfd.c
===================================================================
RCS file: /cvs/src/src/bfd/bfd.c,v
retrieving revision 1.81
diff -u -p -r1.81 bfd.c
--- bfd.c	16 Mar 2006 12:20:15 -0000	1.81
+++ bfd.c	4 May 2006 18:37:57 -0000
@@ -783,6 +783,10 @@ bfd_assert (const char *file, int line)
 void
 _bfd_abort (const char *file, int line, const char *fn)
 {
+#ifdef USE_EXIT_NORETURN
+  /* Make sure the compiler knows _exit doesn't return.  */
+  extern void _exit (int) ATTRIBUTE_NORETURN;
+#endif
   if (fn != NULL)
     (*_bfd_error_handler)
       (_("BFD %s internal error, aborting at %s line %d in %s\n"),