Incorporating OpenCoarrays into gfortran builds automatically

[Damian Rouson <damian at sourceryinstitute dot org>]

Dear gfortran developers,

At the request of Fortran committee members Dan Nagle and Bill Long, I am soliciting feedback about working toward the automatic building of OpenCoarrays as part of the gfortran build. Please let me know your thoughts about the following proposed future workflow:  

1. All new commits to OpenCoarrays would continue to be pushed to the current BSD-licensed repository on GitHub.  
2. New commits to the BSD-licensed repository would be pulled into a GPL fork frequently (at least every time OpenCoarrays releases).
3. GCC’s contrib/download_prerequisites script would be modified to download the OpenCoarrays GPL fork.
4. GCC’s autotools configure script would be modified to set up for building and installing OpenCoarrays, including the following:
   a.) The default libcaf_mpi.a static library that supports building multi-image executable files.
   b.) The default “caf” bash script that can be used to build coarray Fortran programs using mpif90 and gfortran (e.g., with "caf hello-world.f90”).
   c.) The default “cafrun” program launcher that launches multi-image executable programs and sets the number of images (e.g., with “cafrun -np 4 ./a.out” for four images)

If others agree that the above is acceptable, I would handle Steps 1-3, and I would solicit help from one of you to handle Step 4. If the Step 4 developer leverages the existing OpenCoarrays installation scripts, I could also offer a small amount of funding for Step 4. The OpenCoarrays installation scripts total over 4,000 lines of bash and CMake logic intended to enhance robustness and portability and the scripts are capable of building the entire tree of OpenCoarrays dependencies (most notably, CMake, MPICH, and gfortran itself).  It would be important to exploit that existing infrastructure to keep development time and costs low. 

I look forward to your feedback. The proposed work will improve the likelihood that supercomputing centers and manufacturers would ship and maintain systems that give users the ability to build multi-image parallel executable programs from coarray source using gfortran.  

Best Regards,  
______________________________________  
Damian Rouson, Ph.D., P.E.
President, Sourcery Institute
A California public-benefit nonprofit corporation
+1-510-600-2992 (mobile)