Re: [ECOS] more __impure_pointer trouble

[Bob Koninckx <bob dot koninckx at mech dot kuleuven dot ac dot be>]

Here it is (__impure_ptr is never referenced, so i did not paste the
output here). As I said before, I build the tools myself (maybe that's
where the problem comes from. Just for completeness, I give you also the
version of my tools.

Bob

powerpc-eabi-gcc --version
powerpc-eabi-gcc (GCC) 3.2.1
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is
NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

powerpc-eabi-ld --version
GNU ld version 2.13.2.1
Copyright 2002 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms
of
the GNU General Public License.  This program has absolutely no
warranty.

powerpc-eabi-nm -u .obj/vbcom.o | fgrep cxa

powerpc-eabi-nm library/vbcom.a | fgrep cxa
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual
         U __cxa_pure_virtual

powerpc-eabi-nm library/vbcom_extras.o | fgrep cxa
         U __cxa_pure_virtual

powerpc-eabi-nm library/sigc++/install/lib/libsigc++.a | fgrep cxa
         U __cxa_pure_virtual
         U __cxa_pure_virtual


On Sun, 2003-03-30 at 17:24, Bart Veer wrote:
> >>>>> "Bob" == Bob Koninckx <bob dot koninckx at mech dot kuleuven dot ac dot be> writes:
> 
>     <snip>
>     Bob>> I still get the unresolved errors for __impure_ptr (i tried
>     Bob>> to put -lsupc++) on every possible location on the command
>     Bob>> line.
> 
>     Bob>> If on the other hand, I change the group statement in the
>     Bob>> eCos linker script from GROUP(libtarget.a libgcc.a) to
>     Bob>> GROUP(libtarget.a libgcc.a libsupc++.a) and I remove -lsupc++
>     Bob>> from the command line, everything links (and appears to run)
>     Bob>> fine.
> 
>     <snip>
>     >> I suggest something like the following:
>     >> 
>     >> .obj/vbcom.o library/vbcom.a library/vbcom_extras.o \
>     >> -L/home/bob/.../lib -lsigc++ -Ttarget.ld -lsupc++
> 
>     Bob> Nope, still get the same link errors ...
> 
>     >> 
>     >> Note the -l for libsigc++, currently you are pulling in everything in
>     >> that library whether it is needed or not. You might also want to think
>     >> about changing vbcom.a to libvbcom.a and using -Llibrary -lvbcom,
>     >> depending on whether or not it is a real library or just a collection
>     >> of object files.
> 
>     Bob> Thanks for the tip :-) didn't know these subtle differences
> 
> Actually, it looks like I was wrong about this. I have come across
> linkers which behaved as I described, but GNU ld seems to be more
> sensible.
> 
> As to the main problem, I do not understand what is going on. The
> linker should now be picking up __cxa_pure_virtual() from eCos rather
> than from libsupc++. A simple testcase with a pure virtual function
> builds fine for powerpc-eabi, in fact there is no need to link with
> -lsupc++ at all. There don't seem to be any uses of
> __cxa_pure_virtual() within libsupc++ itself, which might have
> confused things. The only other reference to impure_ptr in libsupc++
> is in the demangling code so possibly that is getting pulled in, or
> there could be references to impure_ptr from elsewhere. Could you try
> the following:
> 
>   powerpc-eabi-nm -u .obj/vbcom.o | fgrep impure_ptr
>   powerpc-eabi-nm -u library/vbcom.a | fgrep impure_ptr
>   powerpc-eabi-nm -u library/vbcom_extras.o | fgrep impure_ptr
>   powerpc-eabi-nm -u /home/bob/.../libsigc++.a | fgrep impure_ptr
> 
>   powerpc-eabi-nm -u .obj/vbcom.o | fgrep cxa_demangle
>   powerpc-eabi-nm -u library/vbcom.a | fgrep cxa_demangle
>   powerpc-eabi-nm -u library/vbcom_extras.o | fgrep cxa_demangle
>   powerpc-eabi-nm -u /home/bob/.../libsigc++.a | fgrep cxa_demangle
> 
> (No need for full details, I just want to know which if any of these
> files reference _impure_ptr and/or __cxa_demangle).
> 
> Changing all but three of the linker scripts at this stage of the 2.0
> release process is undesirable, even if it is the correct long-term
> solution. It would partially invalidate much of the testing done so
> far. We may have to do it, but if we can find some simple workaround
> that would be preferable.
> 
> Bart
> 
> -- 
> Bart Veer                       eCos Configuration Architect
> http://www.ecoscentric.com/     The eCos and RedBoot experts
-- 
----------------------------------------------------------------------
ir. Bob Koninckx
Katholieke Universiteit Leuven
Division Production Engineering,                   tel.  +32 16 322535
Machine Design and Automation                      fax.  +32 16 322987
Celestijnenlaan 300B                  bob dot koninckx at mech dot kuleuven dot ac dot be
B-3001 Leuven Belgium               http://www.mech.kuleuven.ac.be/pma
----------------------------------------------------------------------


-- 
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss