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Re: AC_NO_EXECUTABLES update for GCC
From: |
Daniel Jacobowitz |
Subject: |
Re: AC_NO_EXECUTABLES update for GCC |
Date: |
Thu, 16 Oct 2003 12:31:01 -0400 |
User-agent: |
Mutt/1.5.1i |
On Thu, Oct 02, 2003 at 12:37:53PM -0400, Daniel Jacobowitz wrote:
> On Wed, Oct 01, 2003 at 07:31:26PM -0400, Daniel Jacobowitz wrote:
> > It turns out that AC_NO_EXECUTABLES wasn't quite what GCC needed. Here's an
> > update, which is. The difference is that it triggers off of
> > AC_NO_EXECUTABLES being encountered at runtime; so that link tests can
> > remain in the configure script but be avoided in the no-executables case.
> > GCC's been using this for several months.
> >
> > When moving it into autoconf proper this could either remain in one place,
> > or have the uses of m4_define/m4_defn replaced by moving the ac_no_link
> > tests to the normal definitions of those macros. I don't know which is
> > nicer, but I'm sending this one since it's the version I've tested properly.
> >
> > [This code triggers building target libiberty and target libstdc++ for
> > cross-compilers to Cygwin; they're built before newlib and winsup, so
> > nothing links yet.]
>
> Removed the MMAP hack, fixed the quoting. So this one's a little
> cleaner.
Reposting now that my assignment is in place.
2003-10-16 Daniel Jacobowitz <address@hidden>
* lib/autoconf/lang.m4 (AC_NO_EXECUTABLES): Override
_AC_COMPILER_EXEEXT to attempt a link. If linking fails,
override AC_LINK_IFELSE.
Index: lib/autoconf/lang.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autoconf/lang.m4,v
retrieving revision 1.165
diff -u -p -r1.165 lang.m4
--- lib/autoconf/lang.m4 3 Sep 2003 00:35:53 -0000 1.165
+++ lib/autoconf/lang.m4 16 Oct 2003 16:22:17 -0000
@@ -351,8 +351,8 @@ AC_DEFUN([AC_REQUIRE_CPP],
# -----------------
# FIXME: The GCC team has specific needs which the current Autoconf
# framework cannot solve elegantly. This macro implements a dirty
-# hack until Autoconf is abble to provide the services its users
-# needs.
+# hack until Autoconf is able to provide the services its users
+# need.
#
# Several of the support libraries that are often built with GCC can't
# assume the tool-chain is already capable of linking a program: the
@@ -363,22 +363,39 @@ AC_DEFUN([AC_REQUIRE_CPP],
# avoid the AC_PROG_CC_WORKS test, that would just abort their
# configuration. The introduction of AC_EXEEXT, enabled either by
# libtool or by CVS autoconf, have just made matters worse.
+#
+# Unlike an earlier version of this macro, using AC_NO_EXECUTABLES does
+# not disable link tests at autoconf time, but at configure time.
+# This allows AC_NO_EXECUTABLES to be invoked conditionally.
AC_DEFUN_ONCE([AC_NO_EXECUTABLES],
[m4_divert_push([KILL])
+m4_divert_text([DEFAULTS], [ac_no_link=no])
-AC_BEFORE([$0], [_AC_COMPILER_EXEEXT_WORKS])
AC_BEFORE([$0], [_AC_COMPILER_EXEEXT])
-
-m4_define([_AC_COMPILER_EXEEXT_WORKS],
-[cross_compiling=maybe
-])
+AC_BEFORE([$0], [AC_LINK_IFELSE])
m4_define([_AC_COMPILER_EXEEXT],
-[EXEEXT=
+[AC_LANG_CONFTEST([AC_LANG_PROGRAM()])
+if AC_TRY_EVAL(ac_link); then
+ ac_no_link=no
+ ]m4_defn([_AC_COMPILER_EXEEXT])[
+else
+ ac_no_link=yes
+ # Setting cross_compile will disable run tests; it will
+ # also disable AC_CHECK_FILE but that's generally
+ # correct if we can't link.
+ cross_compiling=yes
+ EXEEXT=
+ _AC_COMPILER_EXEEXT_CROSS
+fi
])
m4_define([AC_LINK_IFELSE],
-[AC_FATAL([All the tests involving linking were disabled by $0])])
+[if test x$ac_no_link = xyes; then
+ ac_tmp=AC
+ AC_MSG_ERROR([Link tests are not allowed after ${ac}_NO_EXECUTABLES.])
+fi
+]m4_defn([AC_LINK_IFELSE]))
m4_divert_pop()dnl
])# AC_NO_EXECUTABLES
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer