Re: canadian cross host mingw: build of liblto_plugin-0.dll fails

[Alexey Neyman <stilor@att.net>]

Hi Titus,


On 09/15/2017 04:33 AM, Titus von Boxberg wrote:
> Alexey, all,
>
> on opensuse linux, I'm trying to build an arm-none toolchain for host mingw-w64
> with a fairly recent crosstool-NG.
> As the build machine compiler I'm using gcc-7.2 from opensuse package
> https://build.opensuse.org/package/show/windows%3Amingw%3Awin64/mingw64-cross-gcc
>
> Everything is going smooth except that in the build step for the final gcc
> libtool refuses to generate the liblto_plugin-0.dll
>
> The command line is:
> ./libtool --tag=CC --tag=disable-static  --mode=link x86_64-host_w64-mingw32-gcc -Wall -O2 -g -pipe -I/home/ELBE/titus/tmp/m32-ctng-m7/.build/HOST-x86_64-w64-mingw32/arm-m7-eabi/buildtools/complibs-host/include -Os -D__USE_MINGW_ACCESS -Wc,-static-libgcc -no-undefined -bindir "/opt/cross/arm-m7-eabi/bin" -module -bindir /opt/cross/arm-m7-eabi/libexec/gcc/arm-m7-eabi/7.2.0  -Wc,../libiberty/libiberty.a  -Xcompiler '-static-libstdc++' -Xcompiler '-static-libgcc' '-L/home/ELBE/titus/tmp/m32-ctng-m7/.build/HOST-x86_64-w64-mingw32/arm-m7-eabi/buildtools/complibs-host/lib' '-lstdc++' '-lm' '-Wl,--stack,12582912' -o liblto_plugin.la -rpath /opt/cross/arm-m7-eabi/libexec/gcc/arm-m7-eabi/7.2.0 lto-plugin.lo
>
> The message is:
> *** Warning: linker path does not have real file for library -lstdc++.
> *** I have the capability to make that library automatically link in when
> *** you link to this library.  But I can only do this if you have a
> *** shared version of the library, which you do not appear to have
> *** because I did check the linker path looking for a file starting
> *** with libstdc++ but no candidates were found. (...for file magic test)
>
> *** Warning: libtool could not satisfy all declared inter-library
> *** dependencies of module liblto_plugin.  Therefore, libtool will create
> *** a static module, that should work as long as the dlopening
> *** application is linked with the -dlopen flag.
>
> libtool is looking into these paths:
> /home/ELBE/titus/tmp/m32-ctng-m7/.build/HOST-x86_64-w64-mingw32/arm-m7-eabi/buildtools/complibs-host/lib
> /usr/x86_64-w64-mingw32/lib
> /usr/x86_64-w64-mingw32/sys-root/mingw/lib
>
> I found that the opensuse c++ runtime package installs libstdc++-6.dll
> into the bin directory of the sysroot
> /usr/x86_64-w64-mingw32/sys-root/mingw/bin
>
> When manually copying libstdc++-6.dll into the sysroot's lib directory, libtool is happy.
>
> Any ideas where to look to get this fixed reliably?
Well, I think this placement is not correct. I am not sure if they did 
any hacks to GCC to search /bin for libraries - but this obviously 
breaks any other scripts which assume /lib as the library directory.

I assume they did that so that the /bin directory, when copied to the 
host, could find this DLL. Maybe they should provide a symlink in /lib 
then. Anyway, it is a problem with opensuse's package and I don't see 
what we can do here in crosstool-NG to remediate this.

You can try the mingw compiler from crosstool-NG by the way, I think it 
uses conventional placement of the libraries.

Regards,
Alexey.