[Bug other/57797] New: configure --enable-languages=c builds libstdc++-v3

[Bug other/57797] New: configure --enable-languages=c builds libstdc++-v3

[earnie at users dot sourceforge.net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

            Bug ID: 57797
           Summary: configure --enable-languages=c builds libstdc++-v3
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: earnie at users dot sourceforge.net

When specifying --enable-languages=c the libstdc++-v3 directory is being
configured and built.  I had to remove the directory from the source to prevent
the build.  Here is the full set of configure options:

--prefix=/mingw --enable-languages=c --disable-sjlj-exceptions --with-dwarf2
--enable-shared --disable-win32-registry --disable-build-poststage1-with-cxx
--enable-version-specific-runtime-libs --host=i686-pc-mingw32
--target=i686-pc-mingw32 --build=i686-pc-mingw32 --disable-multilib
--without-pic --with-gnu-ld --with-gnu-as --without-readline
--disable-libstdcxx --enable-lto --enable-multilib --enable-multiarch
--disable-tls --enable-threads --disable-cxx --enable-assembly --enable-fft
--disable-nls --disable-rpath

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|other                       |bootstrap

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Earnie from comment #0)
> --disable-build-poststage1-with-cxx

You know this doesn't work for GCC 4.8, right?

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[earnie at users dot sourceforge.net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

--- Comment #2 from Earnie <earnie at users dot sourceforge.net> ---
(In reply to Jonathan Wakely from comment #1)
> (In reply to Earnie from comment #0)
> > --disable-build-poststage1-with-cxx
> 
> You know this doesn't work for GCC 4.8, right?

No, I wasn't aware of it.  I copied it from a previous 4.7.2 build via ``gcc
-v''.

But that shouldn't cause the issue.  I notice in the target folder
i686-pc-mingw32/libgcc/config.log file that --enable-languages is modified to
include c++ and lto.  Why would that happen?

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[ktietz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

Kai Tietz <ktietz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |ktietz at gcc dot gnu.org
         Resolution|---                         |INVALID

--- Comment #3 from Kai Tietz <ktietz at gcc dot gnu.org> ---
gcc requires c++ for building and bootstrap.  Therefore libstdc++ isn't disable
and has to be built for stage 1 and stage 2.

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[earnie at users dot sourceforge.net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

Earnie <earnie at users dot sourceforge.net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |---

--- Comment #4 from Earnie <earnie at users dot sourceforge.net> ---
Kai,

Your statement doesn't resolve anything at all.  It is fine for gcc to require
c++ but it is not fine for configure to continue if I only specify c and c++ is
also built without an error being issued by configure stating that c++ is
required.  Previous versions of GCC I was able to build only c and c++ wasn't
considered.

Secondly, what is wrong with the process using an already installed c++ version
to build gcc when only c is requested to be built?  I should be able to expect
to build only the language compiler requested without another language compiler
being built along with it.

Earnie

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

--- Comment #5 from Mikael Pettersson <mikpe at it dot uu.se> ---
(In reply to Earnie from comment #4)
> Your statement doesn't resolve anything at all.  It is fine for gcc to
> require c++ but it is not fine for configure to continue if I only specify c
> and c++ is also built without an error being issued by configure stating
> that c++ is required.  Previous versions of GCC I was able to build only c
> and c++ wasn't considered.
> 
> Secondly, what is wrong with the process using an already installed c++
> version to build gcc when only c is requested to be built?  I should be able
> to expect to build only the language compiler requested without another
> language compiler being built along with it.

Use --disable-bootstrap for a native compiler if you want only C.

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[ktietz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

Kai Tietz <ktietz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #6 from Kai Tietz <ktietz at gcc dot gnu.org> ---
It doesn't resolve anything.  It just describes a fact that a bootstrap of gcc
without c++ beginning with 4.8+ isn't possible.  So for stage1 and stage2 there
has to be built a c++ compiler plus library due otherwise no bootstrap can be
done.
If you want to build only c then you have to use --disable-bootstrap for a
native compiler if you want only C.

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[earnie at users dot sourceforge.net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

--- Comment #7 from Earnie <earnie at users dot sourceforge.net> ---
--disable-bootstrap is an answer I can live with as resolving this issue.  Use
of --disable-build-poststage1-with-cxx should become an error in configure with
the suggestion to use --disable-bootstrap instead.

[Bug bootstrap/57797] configure --enable-languages=c builds libstdc++-v3

[ktietz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57797

--- Comment #8 from Kai Tietz <ktietz at gcc dot gnu.org> ---
please note that bugzilla isn't the proper place to get end-user support about
how to use options.  To cite your favorite sentence  "please read first the
mail-archive".  Actually you weren't the first person having this question.
Such questions are better placed at gcc-help.