Re: Boost ABI/Linkage of clang vs g++

From: degski (degski_at_[hidden])
Date: 2020-07-17 01:46:50

the reality is that most of us have no time to read the fuckin'docs, coz my
wife would like diner in time today. Boost is not helpful in maintaining my
family-relationships. The latter are my top-priorities. More and more Boost
is in-compatible with my definition of being a happy chappy and based on
this I try to avoid Boost, becoz daddy has to work to much, reading all
that old shit a.o.t. helping me to fix a small bit of irrelevant (in the
global picture) without getting a cross-examination to determine whether we
would like to help degski to achieve his main goal in life, that is to say
taking care of my loved ones some of them carrying half my genes (i.e. a
bad copy of myself, they call those children, they are in the branch devel.
and they are the future.

On Thu, 9 Jul 2020 at 18:52, Paul A. Bristow via Boost-users <
boost-users_at_[hidden]> wrote:

>
>
> > -----Original Message-----
> > From: Boost-users <boost-users-bounces_at_[hidden]> On Behalf Of DV
> Henkel-Wallace via Boost-
> > users
> > Sent: 9 July 2020 15:41
> > To: Mathias Gaunard <mathias.gaunard_at_[hidden]>
> > Cc: DV Henkel-Wallace <gumby_at_[hidden]>;
> boost-users_at_[hidden]
> > Subject: Re: [Boost-users] Boost ABI/Linkage of clang vs g++
> >
> >
> > > On Jul 9, 2020, at 04:25, Mathias Gaunard <
> mathias.gaunard_at_[hidden]> wrote:
> > >
> > > On Thu, 9 Jul 2020 at 08:07, DV Henkel-Wallace via Boost-users
> > > <boost-users_at_[hidden]> wrote:
> > >
> > >> We build with clang++-10 w/libc++.a and g++-10 w/libstdc++.a, so
> > >> build a copy of boost in each configuration as well.  This works
> > >> great on the Mac development machines but the clang case doesn't
> > >> generate the correct linkage on the Linux deployment machines.  The
> > >> correct clang linkage is std::__1::basic_string... but boost builds
> > >> with std::__cxx11::basic_string
> > >
> > > libc++ is not binary compatible with libstdc++.
> > > You need to use either libstdc++ or libc++ with both compilers if you
> > > want binary compatibility.
> > >
> > > This doesn't have anything to do with Boost.
> >
> > Thanks Mathias.  I did not express my problem clearly.  This is a b2
> issue; I doubt any _library source
> > code_ has any direct interaction with this and I'm sorry if I
> accidentally gave that impression.  Is there a
> > way to get b2 to disgorge the environment and tool invocation of each
> step (basically what is passed to
> > system() or exec())?
> >
> > The background, perhaps clarified:
> >
> > We have our own code, some third party code (like Boost) and of course
> different runtime platforms
> > (Mac, iOS, Linux...).  Since different platforms use different
> compilers/runtimes as their "native" stack,
> > our development system builds everything end-to-end with both gcc and
> clang to catch problems as
> > early as possible.  All compilation is with c++14 or later, post the
> C++11 ABI break, hence the naming
> > issues.  This process isolates us from any system libraries that don't
> have C linkage.
> >
> > Therefore g++ is used to compile libstdc++, boost, other third party
> code, and our code.  Symbols are
> > generated that use __c++11:: in their name.
> > And clang++ is used to compile libc++, boost, other third party code,
> and our code.  Symbols are
> > generated that use use __1:: in their name.
> >
> > But boost itself is compiled via b2 and what is passed to the compiler
> (and which compiler b2 chooses) is
> > quite opaque.  Despite my attempts to force the use of clang it appears
> that b2 is either calling g++ or
> > otherwise asking clang to use g++-style symbol linkage on Linux. On the
> Mac the same invocation
> > behaves as expected.
> >
> > I'm compiling boost this way:
> >
> > export CC=clang CXX="clang++ -stdlib=libc++" CXXSTD=c++20 ; ./b2
> stdlib=libc++ toolset=clang
> > boost.locale.icu=off boost.locale.std=off --with-atomic --with-chrono
> --with-date_time --with-headers --
> > with-locale --with-log --with-program_options --with-random --with-regex
> --with-system --with-thread
> > threading=multi -sNO_COMPRESSION=1 link=static install
> >
> > Any thoughts on how to debug this?
>
> Does b2 -debug-configuration help?
>
> https://boostorg.github.io/build/manual/master/index.html   section 3.3
> configuration
>
> ☀
>         You can use the --debug-configuration option to find which
> configuration files are actually loaded.
>
> Paul
>
>
>
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