Add Flang as fortran compiler in compilers PG.

[rfj82982]

I am trying to have flang, which is now part of macport, as fortran compiler for mpich instead of gcc. I try few configure options as described in this page CompilerSelection, however I always end up to have gcc as fortran compiler. What is the full syntax to force flang instead of gcc? Is this option available. Would be good if among the fortran option for variants flang would be available and would make more sense to have flang as fortran compiler instead of gcc. Same issue seems also to be affecting the openmpi-clang port

[kencu (Ken)]

flang is not considered ready for general use yet, although it continually gets closer.

Maybe late 2024, or 2025?

Here’s an example of many status documents you can find:

​https://linaro.atlassian.net/wiki/spaces/LLVM/pages/28687990785/Flang+support+in+LLVM+FLANG

Generally speaking, MacPorts tries not to use compilers and toolchains that are broken/not ready, as build errors and bugs show up, and useless tickets get opened because we are not flang developers and can’t fix them.

[rfj82982]

Hi Ken thanks for your quick reply. I am aware that flang is not mature yet, but we are looking into supporting it in our development of our library. My issue is the library has MPI as mandatory requirement therefore having only flang on its own is not good for me. Having flang+MPI directly on my machine instead of a remote/cloud would he useful. I'll try to find a way around and I'll keep an eye for when flang will be fully supported by any MPI in macport.

Thanks

[eborisch (Eric A. Borisch)]

This should be addressed first in the compilers portgroup. Once that is ready, we can start looking at adding it to mpich / openmpi.

[cjones051073 (Chris Jones)]

I'm not the maintainer of the compilers PG (they don't rally have maintainers as such) and I am unlikely to implement this myself, certainly not in the forseable future.

[kencu (Ken)]

and flang is still not ready to use as a fortran compiler anyway