[Bug libstdc++/96657] New: libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[Bug libstdc++/96657] New: libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[james.hilliard1 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

            Bug ID: 96657
           Summary: libsupc++.a missing required functions from
                    src/c++98/atomicity.cc when atomic builtins are not
                    supported
           Product: gcc
           Version: 9.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: james.hilliard1 at gmail dot com
                CC: redi at gcc dot gnu.org
  Target Milestone: ---

We've been hitting a bug in buildroot with an application(apcupsd) that links
against libsupc++.a directly.

This issue appears to be due to a sparc/arc specific missing symbols bug in
libsupc++, we aren't seeing this build error for any other architectures at the
moment.

See discussions:
http://lists.busybox.net/pipermail/buildroot/2020-May/282779.html
http://lists.busybox.net/pipermail/buildroot/2020-August/289413.html

Build error
http://autobuild.buildroot.org/results/3be/3bedf404de0ea42ee3ba624cded65d310a847af9//build-end.log:

/tmp/instance-0/output-1/host/opt/ext-toolchain/bin/../lib/gcc/sparc-buildroot-linux-uclibc/8.3.0/../../../../sparc-buildroot-linux-uclibc/bin/ld:
/tmp/instance-0/output-1/host/opt/ext-toolchain/bin/../lib/gcc/sparc-buildroot-linux-uclibc/8.3.0/../../../../sparc-buildroot-linux-uclibc/lib/libsupc++.a(eh_throw.o):
in function `__gxx_exception_cleanup(_Unwind_Reason_Code, _Unwind_Exception*)':
eh_throw.cc:(.text._ZL23__gxx_exception_cleanup19_Unwind_Reason_CodeP17_Unwind_Exception+0x38):
undefined reference to `__gnu_cxx::__exchange_and_add(int volatile*, int)'
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:33: apcupsd] Error 1

Based on previous
discussions(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70560#c6) it appears
this has been broken since r244051 enabled std::exception_ptr for targets
without lock-free atomic built-ins.

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-08-17
            Summary|libsupc++.a missing         |[9/10/11 Regression]
                   |required functions from     |libsupc++.a missing
                   |src/c++98/atomicity.cc when |required functions from
                   |atomic builtins are not     |src/c++98/atomicity.cc when
                   |supported                   |atomic builtins are not
                   |                            |supported

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think r244051 caused libsupc++.a to depend on libstdc++.so for targets that
don't support lock-free atomics for int.

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[james.hilliard1 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

--- Comment #2 from James Hilliard <james.hilliard1 at gmail dot com> ---
(In reply to Jonathan Wakely from comment #1)
> I think r244051 caused libsupc++.a to depend on libstdc++.so for targets
> that don't support lock-free atomics for int.

Yeah, the current workaround we came up with was to force linking to
libstdc++.so, but that's probably not a real fix for the root cause of the
issue. I'm assuming the real fix would be to change libsupc++.a so that it
includes the missing symbols?

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes, I think that's what we need to do.

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |9.4
             Target|                            |sparc, arc

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
For completeness, here's a testcase which fails on sparc64-unknown-linux-gnu
when compiled using gcc -m32 eh.C -lsupc++

#include <exception>

int main()
{
  std::make_exception_ptr(1);
}

/usr/bin/ld:
/home/jwakely/gcc/11/lib/gcc/sparc64-unknown-linux-gnu/11.0.1/../../../../lib32/libsupc++.a(eh_ptr.o):
in function `__gnu_cxx::__exchange_and_add_dispatch(int*, int)':
/home/jwakely/build/sparc64-unknown-linux-gnu/32/libstdc++-v3/include/ext/atomicity.h:101:
undefined reference to `__gnu_cxx::__exchange_and_add(int volatile*, int)'
/usr/bin/ld:
/home/jwakely/gcc/11/lib/gcc/sparc64-unknown-linux-gnu/11.0.1/../../../../lib32/libsupc++.a(eh_ptr.o):
in function `__gnu_cxx::__atomic_add_dispatch(int*, int)':
/home/jwakely/build/sparc64-unknown-linux-gnu/32/libstdc++-v3/include/ext/atomicity.h:111:
undefined reference to `__gnu_cxx::__atomic_add(int volatile*, int)'
/usr/bin/ld:
/home/jwakely/gcc/11/lib/gcc/sparc64-unknown-linux-gnu/11.0.1/../../../../lib32/libsupc++.a(eh_ptr.o):
in function `__gnu_cxx::__exchange_and_add_dispatch(int*, int)':
/home/jwakely/build/sparc64-unknown-linux-gnu/32/libstdc++-v3/include/ext/atomicity.h:101:
undefined reference to `__gnu_cxx::__exchange_and_add(int volatile*, int)'
/usr/bin/ld:
/home/jwakely/gcc/11/lib/gcc/sparc64-unknown-linux-gnu/11.0.1/../../../../lib32/libsupc++.a(eh_ptr.o):
in function `__gnu_cxx::__atomic_add_dispatch(int*, int)':
/home/jwakely/build/sparc64-unknown-linux-gnu/32/libstdc++-v3/include/ext/atomicity.h:111:
undefined reference to `__gnu_cxx::__atomic_add(int volatile*, int)'
/usr/bin/ld:
/home/jwakely/gcc/11/lib/gcc/sparc64-unknown-linux-gnu/11.0.1/../../../../lib32/libsupc++.a(eh_throw.o):
in function `__gnu_cxx::__exchange_and_add_dispatch(int*, int)':
/home/jwakely/build/sparc64-unknown-linux-gnu/32/libstdc++-v3/include/ext/atomicity.h:101:
undefined reference to `__gnu_cxx::__exchange_and_add(int volatile*, int)'
collect2: error: ld returned 1 exit status

[Bug libstdc++/96657] [9/10/11 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:6c0c7fc6236470a533675cd3cd1ebb1cc3dd112c

commit r11-8198-g6c0c7fc6236470a533675cd3cd1ebb1cc3dd112c
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Apr 14 20:48:54 2021 +0100

    libstdc++: Move atomic functions to libsupc++ [PR 96657]

    The changes for PR libstdc++/64735 mean that libsupc++ function might
    now depend on the __exchange_and_add and __atomic_add functions defined
    in config/cpu/*/atomicity.h which is not compiled into libsupc++. This
    causes a link failure for some targets when trying to use libsupc++
    without the rest of libstdc++.

    This patch simply moves the definitions of those functions into
    libsupc++ so that they are available there.

    libstdc++-v3/ChangeLog:

            PR libstdc++/96657
            * libsupc++/Makefile.am: Add atomicity.cc here.
            * src/c++98/Makefile.am: Remove it from here.
            * libsupc++/Makefile.in: Regenerate.
            * src/c++98/Makefile.in: Regenerate.
            * testsuite/18_support/exception_ptr/96657.cc: New test.

[Bug libstdc++/96657] [9/10 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[9/10/11 Regression]        |[9/10 Regression]
                   |libsupc++.a missing         |libsupc++.a missing
                   |required functions from     |required functions from
                   |src/c++98/atomicity.cc when |src/c++98/atomicity.cc when
                   |atomic builtins are not     |atomic builtins are not
                   |supported                   |supported

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed on trunk. Backports to follow.

[Bug libstdc++/96657] [8/9/10 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |NEW
           Assignee|redi at gcc dot gnu.org            |unassigned at gcc dot gnu.org

[Bug libstdc++/96657] [9/10 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|9.4                         |9.5

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9.4 is being released, retargeting bugs to GCC 9.5.

[Bug libstdc++/96657] [9/10 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:f2074277aa3ce0848429e34d6149ba26ff3b708e

commit r10-9997-gf2074277aa3ce0848429e34d6149ba26ff3b708e
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Apr 14 20:48:54 2021 +0100

    libstdc++: Move atomic functions to libsupc++ [PR 96657]

    The changes for PR libstdc++/64735 mean that libsupc++ function might
    now depend on the __exchange_and_add and __atomic_add functions defined
    in config/cpu/*/atomicity.h which is not compiled into libsupc++. This
    causes a link failure for some targets when trying to use libsupc++
    without the rest of libstdc++.

    This patch simply moves the definitions of those functions into
    libsupc++ so that they are available there.

    libstdc++-v3/ChangeLog:

            PR libstdc++/96657
            * libsupc++/Makefile.am: Add atomicity.cc here.
            * src/c++98/Makefile.am: Remove it from here.
            * libsupc++/Makefile.in: Regenerate.
            * src/c++98/Makefile.in: Regenerate.
            * testsuite/18_support/exception_ptr/96657.cc: New test.

    (cherry picked from commit 6c0c7fc6236470a533675cd3cd1ebb1cc3dd112c)

[Bug libstdc++/96657] [9 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
            Summary|[9/10 Regression]           |[9 Regression] libsupc++.a
                   |libsupc++.a missing         |missing required functions
                   |required functions from     |from src/c++98/atomicity.cc
                   |src/c++98/atomicity.cc when |when atomic builtins are
                   |atomic builtins are not     |not supported
                   |supported                   |

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Also fixed for 10.4 now

[Bug libstdc++/96657] [9 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:ba5e10a8c84f56bb2838adb6d1cc9b74741ac4f1

commit r9-9640-gba5e10a8c84f56bb2838adb6d1cc9b74741ac4f1
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Apr 14 20:48:54 2021 +0100

    libstdc++: Move atomic functions to libsupc++ [PR 96657]

    The changes for PR libstdc++/64735 mean that libsupc++ function might
    now depend on the __exchange_and_add and __atomic_add functions defined
    in config/cpu/*/atomicity.h which is not compiled into libsupc++. This
    causes a link failure for some targets when trying to use libsupc++
    without the rest of libstdc++.

    This patch simply moves the definitions of those functions into
    libsupc++ so that they are available there.

    libstdc++-v3/ChangeLog:

            PR libstdc++/96657
            * libsupc++/Makefile.am: Add atomicity.cc here.
            * src/c++98/Makefile.am: Remove it from here.
            * libsupc++/Makefile.in: Regenerate.
            * src/c++98/Makefile.in: Regenerate.
            * testsuite/18_support/exception_ptr/96657.cc: New test.

    (cherry picked from commit 6c0c7fc6236470a533675cd3cd1ebb1cc3dd112c)

[Bug libstdc++/96657] [9 Regression] libsupc++.a missing required functions from src/c++98/atomicity.cc when atomic builtins are not supported

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96657

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
And also fixed for 9.5

The GCC 8.x branch is closed, so it can't be fixed there.