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Re: [v3] Link libstdc++.so with -pthread on Tru64 UNIX (PR target/45693)
- From: Ralf Wildenhues <Ralf dot Wildenhues at gmx dot de>
- To: Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>
- Cc: gcc-patches at gcc dot gnu dot org, libstdc++ at gcc dot gnu dot org
- Date: Tue, 2 Nov 2010 19:51:30 +0100
- Subject: Re: [v3] Link libstdc++.so with -pthread on Tru64 UNIX (PR target/45693)
- References: <ydd39rq1irs.fsf@manam.CeBiTec.Uni-Bielefeld.DE> <ydd39rj7l4u.fsf@manam.CeBiTec.Uni-Bielefeld.DE>
Hello Rainer,
* Rainer Orth wrote on Tue, Nov 02, 2010 at 05:20:17PM CET:
> > As indicated in the PR, all C++ EH tests on Tru64 UNIX were failing
> > since TLS (emutls in this case) was enabled by an unrelated patch. The
> > problem is the same as in PR PR target/46131: emutls relies on a couple
> > of libpthread functions. While there are dummy implementations in
> > libgcc, of course we need the real thing here. The proper solution is
> > to link libstdc++.so with -pthread here (instead of, e.g., linking with
> > -lpthread in g++), so EH doesn't always work, even if linked with
> > another driver or in a mixed-language problem. Manual testing indicated
> > that this fixes the problem as expected. alpha-dec-osf5.1b testing in
> > progress, will commit once completed successfully.
>
> While the idea was sound, actual testing revealed two problems:
>
> * The osf* case also needs to set os_include_dir.
>
> * Cannot use -pthread in OPT_LDFLAGS: libtool swallows that,
> -Wl,-pthread doesn't work (it's not a linker option), and -Wc,-pthread
> doesn't work either (seems to be ignored with -shared), so I had to
> fall back to using -lpthread instead.
Both -pthread and -Wc,-pthread should have worked. Please show logs
that indicate that it was swallowed. libtool has specific code to
allow through -pthread, I'm not aware of bugs in that area.
Thanks,
Ralf
> 2010-10-28 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
>
> PR target/45693
> * configure.host (osf*): Set os_include_dir to os/generic.
> Add -lpthread to OPT_LDFLAGS.
>
> diff -r 3048db040dd6 libstdc++-v3/configure.host
> --- a/libstdc++-v3/configure.host Fri Oct 29 17:12:46 2010 +0000
> +++ b/libstdc++-v3/configure.host Sat Oct 30 11:43:36 2010 +0200
> @@ -261,6 +261,13 @@
> netbsd*)
> os_include_dir="os/bsd/netbsd"
> ;;
> + osf*)
> + os_include_dir="os/generic"
> + # libstdc++.so relies on emutls on Tru64 UNIX, which only works with the
> + # real functions implemented in libpthread.so, not with the dummies in
> + # libgcc, so always pass -lpthread.
> + OPT_LDFLAGS="${OPT_LDFLAGS} -lpthread"
> + ;;
> qnx6.[12]*)
> os_include_dir="os/qnx/qnx6.1"