OpenMPI fails to build with F18

[eugeneswalker]

I'm trying to build OpenMPI 4.0.3 using Clang 9.0.1 and F18, with gfortran 7.3.0 as the backend for F18. The system is Ubuntu 18.04 x86_64. OpenMPI source fetched from http://www.open-mpi.org/software/ompi/v4.0/downloads/openmpi-4.0.3.tar.bz2

The build is failing during configure phase:

    '/tmp/root/spack-stage/spack-stage-openmpi-4.0.3-32tvapmntgmsoawg2eowyvtc6szvpgfu/spack-src/configure' '--prefix=/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/openmpi-4.0.3-32tvapmntgmsoawg2eowyvtc6szvpgfu' '--enable-shared' '--disable-silent-rules' '--with-wrapper-ldflags=' '--enable-static' '--without-pmi' '--enable-mpi-cxx' '--with-zlib=/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/zlib-1.2.11-y64uypcj7qpkhqxac7y2gjnymy3em6fx' '--enable-mpi1-compatibility' '--without-psm2' '--without-mxm' '--without-libfabric' '--without-psm' '--without-verbs' '--without-ucx' '--without-tm' '--without-sge' '--without-lsf' '--without-loadleveler' '--without-alps' '--without-slurm' '--disable-memchecker' '--with-hwloc=/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/hwloc-1.11.11-rmr6go23gjfdzgiyft4y5bkg6zrklwp4' '--disable-java' '--disable-mpi-java' '--without-cuda' '--enable-cxx-exceptions'
1 error found in build log:
     570    checking if building Fortran mpif.h bindings... yes
     571    checking if Fortran compiler supports INTERFACE... yes
     572    checking if Fortran compiler supports ISO_FORTRAN_ENV... no
     573    checking if Fortran compiler supports STORAGE_SIZE for relevant types... no
     574    checking for Fortran compiler module include flag...
     575    configure: WARNING: *** Could not determine the fortran compiler flag to indicate where modules reside
  >> 576    configure: error: *** Cannot continue

Here is config.log : config.log.txt

[jsquyres]

I'm not 100% sure, but I'm guessing we're not explicitly testing the F18 compiler.

What's the F18 flag to specify the path where modules can be found?

[zbeekman]

It looks like the problem is that the compiler is returning a non-zero exit status when it is using the correct module include flag. When the wrong include flag is used, f18/flang print:

/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.5.0/f18-master-j7tbqlr3llsvoe4hbej7lvcazup4qehk/bin/f18: semantic errors in conftest.f90
configure:68682: $? = 1
configure:68696: /opt/spack/lib/spack/env/clang/flang  -fexceptions  conftest.f90 subdir/conftest-module.o                                           -psubdir   -L/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/zlib-1.2.11-y64uypcj7qpkhqxac7y2gjnymy3em6fx/lib -fexceptions  -lz
conftest.f90:2:7: error: Error reading module file for module 'ompi_mod_flag'
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: Could not open 'ompi_mod_flag.mod': No such file or directory

When -I is passed you get a different error:

configure:68607: checking for Fortran compiler module include flag
configure:68631: /opt/spack/lib/spack/env/clang/flang  -fexceptions  -c conftest-module.f90   -L/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/zlib-1.2.11-y64uypcj7qpkhqxac7y2gjnymy3em6fx/lib -fexceptions  -lz
configure:68638: $? = 0
configure:68675: /opt/spack/lib/spack/env/clang/flang  -fexceptions  conftest.f90 -Isubdir   -L/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/zlib-1.2.11-y64uypcj7qpkhqxac7y2gjnymy3em6fx/lib -fexceptions  -lz
conftest.f90:2:7: error: Error reading module file for module 'ompi_mod_flag'
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: Incomplete character literal
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: error: Error reading module file for module 'ompi_mod_flag'
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: Incomplete character literal
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.5.0/f18-master-j7tbqlr3llsvoe4hbej7lvcazup4qehk/bin/f18: semantic errors in conftest.f90
configure:68682: $? = 1
configure:68696: /opt/spack/lib/spack/env/clang/flang  -fexceptions  conftest.f90 subdir/conftest-module.o                                           -Isubdir   -L/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/clang-9.0.1/zlib-1.2.11-y64uypcj7qpkhqxac7y2gjnymy3em6fx/lib -fexceptions  -lz
conftest.f90:2:7: error: Error reading module file for module 'ompi_mod_flag'
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: Incomplete character literal
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: error: Error reading module file for module 'ompi_mod_flag'
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
conftest.f90:2:7: Incomplete character literal
    use OMPI_MOD_FLAG
        ^^^^^^^^^^^^^
/opt/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.5.0/f18-master-j7tbqlr3llsvoe4hbej7lvcazup4qehk/bin/f18: semantic errors in conftest.f90
/usr/lib/x86_64-linux-gnu/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status
configure:68705: $? = 1

Is there a way to see the entire contents of conftest.f90? (And also the source file that generated OMPI_MOD_FLAG in subdir?)

In addition, it seems like the intrinsic modules ISO_Fortran_ENV and ISO_C_BINDING are not being located. It looks like maybe -intrinsic-module-directory also needs to be added and point to the correct location. (I guess the GFortran 7.5 intrinsic module directory?)

[zbeekman]

This looks to me like the ompi_mod_flag.mod file may have been generated with a different Fortran compiler? If it was generated with GFortran you can gunzip it and examine the contents of the .mod file as plain text.

[zbeekman]

@jsquyres FYI, after testing some more (manually) this appears (to me at least) to be either an F18 bug, or a configuration/toolchain issue. -I should be the correct include flag, but running the simple code by hand from https://github.com/open-mpi/ompi/blob/master/config/ompi_fortran_find_module_include_flag.m4 will reproduce the problem.

[coti]

Hi,

I have the problem too. We have contacted the f18 team on Slack and we got an answer. It is related to what is described in flang-compiler/f18#1011.

Short version: binary modules compiled with f18 are actually compiled by the backend compiler, which can be gfortran. Therefore, they cannot be used by f18. We need to get a text module. For this, the module and the resulting file need to be compiled with -module-suffix .f18.mod.

When we compile the module with:

$ f18 -module-suffix .f18.mod -c conftest-module.f90

It generates two files:

ompi_mod_flag.f18.mod
ompi_mod_flag.mod

The first one is a text module that can be used by f18.

$ cat ompi_mod_flag.f18.mod
!mod$ v1 sum:cc0b4f1869785c46
module ompi_mod_flag
type::ompi_mod_flag_type
integer(4)::i
end type
end

Then we can compile the second one:

$ f18 -module-suffix .f18.mod -c conftest.f90

Edit: I can compile OpenMPI 4.0.3 using FCFLAGS="-module-suffix .f18.mod" almost

[coti]

Hi,
I have made some significant progress in compiling OpenMPI. I had to modify the libtool script: in the FC tag section, there was:
wl=""
which I have replaced by
wl="-Wl,"

Then I get a new error:

gfortran: warning: ../../../../ompi/mpi/fortran/mpif-h/.libs/libmpi_mpifh.so: linker input file unused because linking not done
gfortran: warning: /home/users/coti/x86/openmpi-4.0.3/ompi/.libs/libmpi.so: linker input file unused because linking not done
gfortran: warning: /home/users/coti/x86/openmpi-4.0.3/orte/.libs/libopen-rte.so: linker input file unused because linking not done
gfortran: warning: /home/users/coti/x86/openmpi-4.0.3/opal/.libs/libopen-pal.so: linker input file unused because linking not done
gfortran: warning: /packages/gcc/8.1/lib/../lib64/libgfortran.so: linker input file unused because linking not done
gfortran: warning: /packages/gcc/8.1/lib/../lib64/libquadmath.so: linker input file unused because linking not done
gfortran: error: libmpi_mpifh.o: No such file or directory
gfortran: error: libmpi.o: No such file or directory
gfortran: error: libopen-rte.o: No such file or directory
gfortran: error: libopen-pal.o: No such file or directory
gfortran: error: libgfortran.o: No such file or directory
gfortran: error: libquadmath.o: No such file or directory

I suspect that there might be another option to fix in libtool, but this is beyond what I know about it...

I have also tried adding pic_flag=" -fPIC" , unsuccessfully.

Thanks

[jsquyres]

Forgive my ignorance, but F18 is not yet a production-quality compiler, right?

If that's correct, I'd prefer to have them fix their issue rather than put in a gnarly workaround in our m4 code (and/or patch Libtool).

[jsquyres]

Given the length of time between responses on this issue, I'm going to close it due to inactivity.

If it turns out that F18 is a production-quality compiler and/or there is a bug we should be fixing here in Open MPI, we can re-open this.