Re: [PATCH 1/1] Add multilib build support for libc target. Libc is build <multilib>-times in seperate sysroot directories. In a last step links are created to reflect the expected multilib structure.

["konrad.gaisler" <konrad@gaisler.com>]

 >From what I see it does absolutely nothing, because ...
>> +           dir="${i%%;*}"
>> +          bdir="$(echo ${dir} | ${sed} -r -e 's:/:\\\\/:g')"
>> +           if [ "${dir}" != "." ]; then
>> +               flags="$(echo $i | ${sed} -r -e 's/^[^;]*;//' -e 's/@/ -/g')";
>> +               CT_DoStep DEBUG "Fixing up multilib location ${CT_SYSROOT_DIR}/${dir}/lib to ${CT_SYSROOT_DIR}/lib/${dir}"
>> +               mkdir -p ${CT_SYSROOT_DIR}/lib/${dir}
>> +               mkdir -p ${CT_SYSROOT_DIR}/usr/lib/${dir}
>> +
>> +               # recreate the symbolic links for multilib
>> +               for f in $(find ${CT_SYSROOT_DIR}/usr/lib/${dir}/ -type l -maxdepth 1); do
> ... of the 'find' here, that scans two newly-created directories (just
> above), so they are empty.
>
> Did you mean to scan "${dir}/usr/lib" and not "usr/lib/${dir}" ?
>
> And what about "${dir}/lib" ?

Is it possible that I missed something here? I think the
first patch I sent included this lines:

do_libc_start_files() {
     cross_cc=$(CT_Which "${CT_TARGET}-gcc")
     if [ "${CT_CC_MULTILIB}" = "y" ]; then
     for i in `${cross_cc} --print-multi-lib 2>/dev/null`; do
             dir=`echo $i | sed -e 's/;.*$//'`;
         if [ "${dir}" = "." ]; then
         true;
         else
         if [ "${CT_USE_SYSROOT}" = "y" ]; then
             # prepare installation redirects
             mkdir -p ${CT_SYSROOT_DIR}/${dir}/usr
             mkdir -p ${CT_SYSROOT_DIR}/lib/${dir}
             mkdir -p ${CT_SYSROOT_DIR}/usr/lib/${dir}
             ln -sf ${CT_SYSROOT_DIR}/usr/lib/${dir} 
${CT_SYSROOT_DIR}/${dir}/usr/lib
             ln -sf ${CT_SYSROOT_DIR}/lib/${dir} 
${CT_SYSROOT_DIR}/${dir}/lib
             fi
         flags=`echo $i | sed -e 's/^[^;]*;//' -e 's/@/ -/g'`;
         CT_DoStep INFO "Installing C library start files multilibbed. 
Flags: ${flags} Dir: ${dir}"
         do_single_libc_start_files "/${dir}" "${flags}"
         CT_EndStep
         fi
     done;
     fi
     do_single_libc_start_files
}

These symlinks that are installed before the glibc
installs make that
${CT_SYSROOT_DIR}/${dir}/usr/lib
end up in
${CT_SYSROOT_DIR}/usr/lib/${dir}
and
${CT_SYSROOT_DIR}/${dir}/lib
end up in
${CT_SYSROOT_DIR}/lib/${dir}

The point here is that glibc's install process adds the /lib at the
end, however the multilib structure must have /lib before:
/lib/<multilib>. Adding these symlinks before makes the
libraries end up in the right place. The "rearrange" stage
then fixes up the wrong paths.
Hope that makes it more clear.

The whole thing might have to be rewritten, I think
you might come up with a solution that is easier.


>
> Besides, the options ordering to the 'find' command is wrong, and 'find'
> complains loudly. No problem, fixed here.
>
>> +                   fn=`basename $f`
>> +                   ln=`readlink $f`
>> +                   ln=`basename $ln`
>> +		   # go toward root. Count the numer of "/" and asseble a "../.." prefix
>> +                   pre=$( echo ${dir} | awk '{r="";
>> +		       c=split($0,b,"/");
>> +		       for(i=0;i<c;i++){
>> +		           if(i!=0){r=r "/";}
>> +			   r=r "..";
>> +		       };
>> +		       printf("%s",r);
>> +		   }')
>> +		   CT_Pushd "${CT_SYSROOT_DIR}/usr/lib/${dir}/"
>> +                   ln -sf ../../${pre}/lib/${dir}/$ln $fn
>> +		   CT_Popd
>> +               done
>> +
>> +               # rewrite the library multiplexers
>> +               for l in libc libpthread libgcc_s; do
>> +                   for d in lib/${dir} usr/lib/${dir}; do
>> +                       if [ -f "${CT_SYSROOT_DIR}/${d}/${l}.so" -a ! -L ${CT_SYSROOT_DIR}/${d}/${l}.so ]; then
>> +                           if [ ! -f "${CT_SYSROOT_DIR}/${d}/${l}.so_ori_i" ]; then
>> +                               cp ${CT_SYSROOT_DIR}/${d}/${l}.so ${CT_SYSROOT_DIR}/${d}/${l}.so_ori_i
>> +                               cat ${CT_SYSROOT_DIR}/${d}/${l}.so_ori_i | ${sed} -r -e "s/\/lib\/$l/\/lib\/$bdir\/$l/g">  ${CT_SYSROOT_DIR}/${d}/${l}.so
> With this sed expression, you are not rewriting the dynamic linker path,
> which means a multilib variant still uses the default "ld.so".
You might be right. My particular toolchain doesnt care as for the
ld.so probably doesnt differ. It is also so that in the final running
embedded-system, there is only one libc set, that is copied back
to /usr/lib. I think buildroot needs a patch to copy the right set
of libc though.

>
> I think the following sed-expr does the trick (and does not require
> the '/' mangling done above):
>      "s:/lib/:/lib/${dir}/:g;"
>
> (mangling ':' in ${dir} is not needed, the dirname can not contain a ':',
> as ':' is the multilib separator in "gcc -print-multi-lib").
>
>> +			   else
>> +			       CT_DoLog WARN "${CT_SYSROOT_DIR}/${d}/${l}.so has already been patched, skipping"
>> +                           fi
>> +                       fi
>> +                   done
>> +               done
>> +               CT_EndStep
>> +           fi
>> +        done;
> In the end, it leaves everything in "sysroot/${dir}".
> It would make much more sense to carefully move the libs in their correct
> place, that is:
>   - move everything from "sysroot/${dir}/lib"     ->  "sysroot/lib/${dir}"
>                      and "sysroot/${dir}/usr/lib" ->  "sysroot/usr/lib/${dir}"
>   - get rid of "sysroot/${dir}" alltogether
>
> That's because gcc will search for things in "sysroot/{usr/,}lib/${dir}/",
> not in "sysroot/${dir}/{usr/,}lib/"
I'm not an insider to glibc, but maybe there is a option to
glibc's configure that create the right multilib structure.
Then all the hustle with moving and or creating symbolic
links  would be unneeded.

>
> Of course, we can go with the symlinks first; once that works, we can look
> into doing the move and clean-up.
>
> [--SNIP--]
>>       case "${CT_ARCH_FLOAT_HW},${CT_ARCH_FLOAT_SW}" in
>> -        y,) extra_config+=("--with-fp");;
>> +        y,) # if it is a<multilib>  build then check if -msoft-float is given
>> +	    if [ "x`expr "${extra_flags}" : '.*-msoft-float.*'`" != "x0" ]; then
>> +	    	extra_config+=("--with-fp=no");
>> +	    else
>> +	    	extra_config+=("--with-fp");
>> +	    fi
>> +	    ;;
>>           ,y) extra_config+=("--without-fp");;
>>       esac
> Floats are not the only thing we have to account for. For example, some
> archs can define big/little multilib. And most probably other stuff
> as well...
Sorry, I dont really know the requirements for other archs, I
come up with this because I require for sparc glibc the --with-fp=no.

>
> Well... Time for some rejoicing !
> Merry X-Mas to All, and a Happy New Year! Cheers !

Merry XMas back. It just has passed.
-- Konrad
>
> Regards,
> Yann E. MORIN.
>


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