Draft: Fortran Support

Testing using level 2

Disqualified Tests:

• Passing NULL/MPI_REQUEST_NULL causes compile errors in Fortran, disqualifying InvalidParam tests that do this
  • Disqualifies 17 tests (lvl1) / 136 (lvl2)
• A lot of tests are currently removed due to datatypes, i.e., MPI C types that do not exist / are not implemented yet for Fortran
  • No effect on lvl1, as only MPI_INT and MPI_DOUBLE are used / 501 disqualified (lvl2)

Unfixable, but not disqualified:

• InvalidParam-Status-mpi_recv-002: MPI_STATUSES_IGNORE rejected by compiler, different rank than expected
  • Error class does not exist for Fortran. Disqualifies 1 test (lvl1) / 16 (lvl2)

MPI Issues:

• https://github.com/open-mpi/ompi/issues/9534 - Causes issues with Precv_Init / Psend_init. Need recent OpenMPI version to avoid this
• https://github.com/open-mpi/ompi/pull/13308 - Bug in OpenMPI-git causes compilation failure as well

Types are translated from C to Fortran where applicable, though currently only for MPI_INT -> MPI_INTEGER, MPI_DOUBLE -> MPI_DOUBLE_PRECISION, MPI_C_BOOL -> MPI_LOGICAL as most Fortran MPI types are optional. Tests are formatted using fprettify (available from pip, added to Pipfile).

Common Issues encountered:

• MPI does not differentiate between bool and int, but does between integer and logical.
  • Workaround: Use bool where applicable in C code, then translate to logical
• Different integer size expectations cause compilation failures (no automatic extension)
  • Workaround: During parsing of apis.json, save the integer width, and perform explicit widening if needed.
• C usage of address-of-integer as a one-dimensional array does not work in Fortran
  • Workaround: Replace uses thereof with proper arrays
• Array Indexing starts at 1
  • Workaround: Implement explicit indexing to match C

MPI-BugBench bugs (since remembering to write them down):

• Deadlock in CallOrdering-mpi_improbe-mpi_send-001, wrong parameter used as flag
  • Note: Deadlock also happens in InvalidParam-flag-mpi_iprobe-002, but intended? (not_allocated flag is not waited on, but the "normal" one)

scripts/Infrastructure/TemplateFactory.py

@@ -909,8 +909,8 @@ def get_intercomm(comm_create_func: str, tm: TemplateManager, before_idx: int =
             tm.insert_instruction(Instruction("local_group = (rank % 2 ? " + even_group + ":" + odd_group + ");"), before_instruction=before_inst)
             tm.insert_instruction(Instruction("remote_group = (!(rank % 2) ? " + even_group + ":" + odd_group + ");"), before_instruction=before_inst)
         else:
-            tm.insert_instruction(Instruction("local_group = merge(" + even_group + ", " + odd_group + ", modulo(rank, 2) == 0)"), before_instruction=before_inst)
-            tm.insert_instruction(Instruction("remote_group = merge(" + even_group + ", " + odd_group + ", modulo(rank, 2) == 1)"), before_instruction=before_inst)
+            tm.insert_instruction(Instruction("local_group = merge(" + even_group + ", " + odd_group + ", modulo(rank, 2) == 1)"), before_instruction=before_inst)
+            tm.insert_instruction(Instruction("remote_group = merge(" + even_group + ", " + odd_group + ", modulo(rank, 2) == 0)"), before_instruction=before_inst)
 
         call = MPICallFactory.mpi_intercomm_create_from_groups("local_group",
                                                                "0",