12-gary-solaris-no-undefined.patch [Was Re: 5-gary-solaris-no-undefined.patch]

[Gary V. Vaughan]

On Sun, Sep 09, 2001 at 01:39:34PM -0500, address@hidden wrote:
> On Sun, Sep 09, 2001 at 12:41:48PM -0500, address@hidden wrote:
> > My results:
> >   1. GCC 2.95.3 without binutils on Solaris 8/SPARC fails (1.4.1)
> >   2. GCC 3.0.1 without binutils on Solaris 8/SPARC succeeds (1.4.1)
> > 
> >   3. GCC 2.95.3 with binutils on Solaris 2.6/SPARC succeeds (1.4.1)
> > 
> >   4. GCC 2.95.3 without binutils on Solaris 8/SPARC succeeds (1.3.5)
> > 
> > Because of #4, I say we reject the patch and find out why 1.3.5
> > succeeded.
> 
> Further research:
>   (from gcc/libgcc2.c in GCC 2.95.3)
> /* This is used by the `assert' macro.  */
> extern void __eprintf (const char *, const char *, unsigned int, const
> char *)
>   __attribute__ ((__noreturn__));
> 
>   (from gcc/libgcc2.c in GCC 3.0)
> /* __eprintf used to be used by GCC's private version of <assert.h>.
>    We no longer provide that header, but this routine remains in libgcc.a
>    for binary backward compatibility.  Note that it is not included in
>    the shared version of libgcc.  */
> 
> I looked at libltdl/ltdl.c in 1.3.5 and it makes *no* calls to assert.
> However, the libltdl/ltdl.c in 1.4.1 does. Remove the assert calls in
> 1.4.1 and we don't have problems :)
> 
> Even if an assert() is added to ltdl.c from 1.3.5, you'll never get an
> error because "-z defs" is not used the build the shared library. I
> inserted an assert() in 1.3.5 and had the same error as with 1.4.1.
> So, it seems the "ugly hack" is needed only when GCC < 3.0 is used and
> GCC has been compiled *without* binutils. Can you incorporate this
> into your patch so the ugliness is localized?
> 
> BTW, have you tried using GCC to created the shared library? I did a
> quick test with 2.95.3 for 1.4.1:
>   $ gcc -shared -Wl,-h,libltdl.so.3 -o .libs/libltdl.so.3.0.0 ltdl.lo -ldl -lc
>   $ nm .libs/libltdl.so.3.0.0 | grep eprintf
>   [242]   |     27140|      72|FUNC |GLOB |0    |10     |__eprintf
> If gcc creating the shared library works, I say use it instead of
> Solaris ld (barring any problem).

According to comments in libtool.m4:

    # $CC -shared without GNU ld will not create a library from C++
    # object files and a static libstdc++, better avoid it by now

I'm proposing the following patch (pending tests), which takes a
slightly different tack.  I'll test it tomorrow, and release it as
part of 1.4.2 if it works.

Cheers,
        Gary.

Index: ChangeLog
from  Gary V. Vaughan  <address@hidden>, Albert Chin <address@hidden>, Tim Van 
Holder <address@hidden>

        * libtool.m4 (no_undefined_flag) [solaris*}: Set this flag to
        unsupported for GCC < 3.0 without binutils.

Index: libtool.m4
===================================================================
RCS file: /cvsroot/libtool/libtool/libtool.m4,v
retrieving revision 1.166.2.23
diff -u -p -u -r1.166.2.23 libtool.m4
--- libtool.m4 2001/09/09 17:20:33 1.166.2.23
+++ libtool.m4 2001/09/09 23:26:29
@@ -1707,7 +1707,33 @@ else
     ;;
 
   solaris*)
-    no_undefined_flag=' -z text'
+    # gcc --version < 3.0 without binutils cannot create self contained
+    # shared libraries reliably, requiring libgcc.a to resolve some of
+    # the object symbols generated in some cases.  Libraries that use
+    # assert need libgcc.a to resolve __eprintf, for example.  Linking
+    # a copy of libgcc.a into every shared library to guarantee resolving
+    # such symbols causes other problems:  According to Tim Van Holder
+    # <address@hidden>, C++ libraries end up with a separate
+    # exception stack for one thing.
+    if test "$GCC" = yes; then
+      case `$CC --version 2>/dev/null` in
+      [12].*)
+       no_undefined_flag=unsupported
+       cat <<EOF 1>&2
+
+*** Warning: Releases of GCC earlier than version 3.0 cannot reliably
+*** create self contained shared libraries on Solaris systems.  Therefore,
+*** libtool is disabling the -no-undefined support.  We urge you to upgrade
+*** to a newer version of GCC.  Another option is to rebuild your current
+*** GCC to use the GNU linker from GNU binutils 2.9.1 or newer.
+
+EOF
+       ;;
+      *)
+        no_undefined_flag=' -z defs'
+       ;;
+      esac
+    fi
     # $CC -shared without GNU ld will not create a library from C++
     # object files and a static libstdc++, better avoid it by now
     archive_cmds='$LD -G${allow_undefined_flag} -h $soname -o $lib $libobjs 
$deplibs $linker_flags'

-- 
  ())_. Gary V. Vaughan     gary@(oranda.demon.co.uk|gnu.org)
  ( '/  Research Scientist  http://www.oranda.demon.co.uk       ,_())____
  / )=  GNU Hacker          http://www.gnu.org/software/libtool  \'      `&
`(_~)_  Tech' Author        http://sources.redhat.com/autobook   =`---d__/