Mikulas Patocka <[EMAIL PROTECTED]> writes:
> Intel compiler's interprocedural optimizations (-ipo) optimizes this
> out even though the symbol is unknown.
Wonderful. (:-)
I installed the following patch to try to catch this.
2005-10-19 Paul Eggert <[EMAIL PROTECTED]>
* doc/autoconf.texi (Generating Sources): AC_LANG_PROGRAMS ->
AC_LANG_PROGRAM, fixing a typo. Don't give details about
the inner workings of AC_LANG_FUNC_LINK_TRY.
* lib/autoconf/c.m4 (AC_LANG_CALL(C)): Reformat to match
AC_LANG_FUNC_LINK_TRY. This involves returning the value returned
by the function rather than ignoring it.
(AC_LANG_FUNC_LINK_TRY(C)): Call the function rather than simply
comparing its address. Intel's interprocedural optimization was
outsmarting the old heuristic. Problem reported by
Mikulas Patocka.
--- doc/autoconf.texi 1 Sep 2005 13:49:02 -0000 1.929
+++ doc/autoconf.texi 19 Oct 2005 22:33:51 -0000
@@ -2997,7 +2997,7 @@ breed: they are executed directly by @fi
Execute the @var{cmds} right before creating @file{config.status}.
This macro presents the last opportunity to call @code{AC_SUBST},
[EMAIL PROTECTED], or @code{AC_CONFIG_FOOS} macros.
[EMAIL PROTECTED], or @code{AC_CONFIG_FOOS} macros.
@end defmac
@defmac AC_CONFIG_COMMANDS_POST (@var{cmds})
@@ -6921,7 +6921,7 @@ fputs (hw, stdout);
@acindex{LANG_CALL}
Expands into a source file which consists of the @var{prologue}, and
then a call to the @var{function} as body of the main function (e.g.,
[EMAIL PROTECTED] in C). Since it uses @code{AC_LANG_PROGRAMS}, the feature
[EMAIL PROTECTED] in C). Since it uses @code{AC_LANG_PROGRAM}, the feature
of the latter are available.
This function will probably be replaced in the future by a version
@@ -6932,10 +6932,9 @@ not encouraged, as it violates strongly
@defmac AC_LANG_FUNC_LINK_TRY (@var{function})
@acindex{LANG_FUNC_LINK_TRY}
-Expands into a source file which consists of a pseudo use of the
[EMAIL PROTECTED] as body of the main function (e.g., @code{main} in C): a
-simple (function pointer) assignment. Since it uses
[EMAIL PROTECTED], the feature of the latter are available.
+Expands into a source file which uses the @var{function} in the body of
+the main function (e.g., @code{main} in C). Since it uses
[EMAIL PROTECTED], the feature of the latter are available.
As @code{AC_LANG_CALL}, this macro is documented only for completeness.
It is considered to be severely broken, and in the future will be
--- lib/autoconf/c.m4 7 Sep 2005 14:43:14 -0000 1.203
+++ lib/autoconf/c.m4 19 Oct 2005 22:33:51 -0000
@@ -162,13 +162,13 @@ $2
m4_define([AC_LANG_CALL(C)],
[AC_LANG_PROGRAM([$1
m4_if([$2], [main], ,
-[/* Override any gcc2 internal prototype to avoid an error. */
+[/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
#ifdef __cplusplus
extern "C"
#endif
-/* We use char because int might match the return type of a gcc2
- builtin and then its argument prototype would still apply. */
-char $2 ();])], [$2 ();])])
+char $2 ();])], [return $2 ();])])
# AC_LANG_FUNC_LINK_TRY(C)(FUNCTION)
@@ -204,26 +204,20 @@ m4_define([AC_LANG_FUNC_LINK_TRY(C)],
#undef $1
-/* Override any gcc2 internal prototype to avoid an error. */
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
#ifdef __cplusplus
extern "C"
-{
#endif
-/* We use char because int might match the return type of a gcc2
- builtin and then its argument prototype would still apply. */
char $1 ();
/* The GNU C library defines this for functions which it implements
to always fail with ENOSYS. Some functions are actually named
something starting with __ and the normal name is an alias. */
#if defined (__stub_$1) || defined (__stub___$1)
choke me
-#else
-char (*f) () = $1;
-#endif
-#ifdef __cplusplus
-}
#endif
-], [return f != $1;])])
+], [return $1 ();])])
# AC_LANG_BOOL_COMPILE_TRY(C)(PROLOGUE, EXPRESSION)
_______________________________________________
Bug-coreutils mailing list
Bug-coreutils@gnu.org
http://lists.gnu.org/mailman/listinfo/bug-coreutils
