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Re: [PATCH] Enable unwind info in libc-start.c and backtrace.c
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- Cc: "H.J. Lu" <hjl dot tools at gmail dot com>, Carlos O'Donell <carlos at redhat dot com>, "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>, nd <nd at arm dot com>, Andreas Schwab <schwab at suse dot de>
- Date: Thu, 14 Sep 2017 15:12:21 +0000
- Subject: Re: [PATCH] Enable unwind info in libc-start.c and backtrace.c
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On Thu, 14 Sep 2017, Wilco Dijkstra wrote:
> H.J. Lu wrote:
>
> > # CC="gcc -m32 -march=i686" CXX="g++ -m32 -march=i686"
> > /export/gnu/import/git/sources/glibc/configure --prefix=/usr
> > --target=i686-linux --build=i686-linux --host=i686-linux
> > --enable-hardcoded-path-in-tests
> >
> > to configure glibc for i686 on Linux/x86-64. It works fine.
>
> Doing it exactly like that I get:
>
> /work/install/binutils_x64/x86_64-linux-gnu/bin/ld: skipping incompatible /work/install/gcc_x64/lib/gcc/x86_64-linux-gnu/8.0.0/libgcc.a when searching for -lgcc
> /work/install/binutils_x64/x86_64-linux-gnu/bin/ld: cannot find -lgcc
>
> So it doesn't seem to be able to find a 32-bit libgcc although that GCC
> supports -m32...
That suggests you have a --disable-multilib compiler.
You can use build-many-glibcs.py to build an x86_64 compiler that supports
all of -m64, -m32, -mx32 (build-many-glibcs.py <dir> checkout;
build-many-glibcs.py <dir> host-libraries; build-many-glibcs.py <dir>
compilers x86_64-linux-gnu). Having got that compiler (in
<dir>/install/compilers/x86_64-linux-gnu) you can then use it for building
/ testing glibc manually (including running execution tests in such a
build - make sure to copy libstdc++ and libgcc_s shared libraries from the
right multilib to the build directory before running make check) if you
want.
--
Joseph S. Myers
joseph@codesourcery.com