Re: libgfortran.so SONAME and powerpc64le-linux ABI changes (work in progress patches)

[Michael Meissner <meissner@linux.ibm.com>]

On Fri, Oct 29, 2021 at 09:07:38PM +0200, Thomas Koenig wrote:
> Hi Michael,
> 
> I tried this out on the one POWER machine where I can get something
> installed :-) It runs Ubuntu 20.04, but does not appear to have the
> right glibc version; it has
> 
> $ lsb_release -a
> No LSB modules are available.
> Distributor ID: Ubuntu
> Description:    Ubuntu 20.04.1 LTS
> Release:        20.04
> Codename:       focal
> $ ldd --version
> ldd (Ubuntu GLIBC 2.31-0ubuntu9.1) 2.31
> 
> Configure was
> 
> ./trunk/configure --prefix=$HOME --enable-languages=c,c++,fortran
> --with-advance-toolchain=at15.0
> --with-native-system-header-dir=/opt/at15.0/include
> --with-long-double-format=ieee
> 
> and the error message
> 
> msgfmt -o fr.mo ../../../../trunk/libstdc++-v3/po/fr.po
> msgfmt: /lib/powerpc64le-linux-gnu/libm.so.6: version `GLIBC_2.32' not found
> (required by /home/ig25/trunk-bin/powerpc64le-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6)
> msgfmt: /lib/powerpc64le-linux-gnu/libc.so.6: version `GLIBC_2.33' not found
> (required by /home/ig25/trunk-bin/powerpc64le-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6)
> msgfmt: /lib/powerpc64le-linux-gnu/libc.so.6: version `GLIBC_2.34' not found
> (required by /home/ig25/trunk-bin/powerpc64le-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6)
> msgfmt: /lib/powerpc64le-linux-gnu/libc.so.6: version `GLIBC_2.32' not found
> (required by /home/ig25/trunk-bin/powerpc64le-unknown-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6)
> msgfmt: /lib/powerpc64le-linux-gnu/libc.so.6: version `GLIBC_2.34' not found
> (required by /home/ig25/trunk-bin/./gcc/libgcc_s.so.1)
> 
> and so on.
> 
> Since gcc135 is also too old, that exhausts my possibilities at testing.
> 
> Any hints on how best to proceed?
> 
> Best regards

As I've delved into it, it looks glibc 2.34 is really only needed for switching
long double over to IEEE 128-bit, since it has all of the F128 functions that
would be needed.  That is because Fortran uses the 'q' names which are in
libquadmath (that should be built).

I built the original version with:

        --prefix=/home/meissner/fsf-install-ppc64le/fortran-orig \
        --enable-languages=c,c++,fortran \
        --disable-plugin \
        --enable-checking \
        --enable-stage1-checking \
        --enable-gnu-indirect-function \
        --disable-libgomp \
        --enable-decimal-float \
        --enable-secureplt \
        --enable-threads=posix \
        --enable-__cxa_atexit \
        --with-long-double-128 \
        --with-long-double-format=ibm \
        --with-cpu=power9 \
        --with-as=/opt/at12.0/bin/as \
        --with-ld=/opt/at12.0/bin/ld \
        --with-gnu-as=/opt/at12.0/bin/as \
        --with-gnu-ld=/opt/at12.0/bin/ld \
        --with-gmp=/home/meissner/tools-compiler/ppc64le \
        --with-mpfr=/home/meissner/tools-compiler/ppc64le \
        --with-mpc=/home/meissner/tools-compiler/ppc64le \
        --without-ppl \
        --without-cloog \
        --without-isl

I needed to build my own version of mpfs, mpc, and gmp.  I built them without
shared libraries, because I get messages like you get.

I have a new version of the patch that makes new target hooks to allow the
backend to specify KIND numbers for types.  I choose kind=16 to always be IEEE
128-bit, and kind=15 to be long double if long double is IBM (since I
discovered yesterday, Fortran needs to be able to deal with long double).  I'm
in the middle of the build an on internal IBM system, and I will start the
build on gcc135 shortly.

-- 
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: meissner@linux.ibm.com