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/Template.py

@@ -346,7 +346,21 @@ class TemplateManager:
             self._stack_variable_inits[name] = init
         self._stack_variable_dims[name] = arr_dim
         return name
-    
+
+    def remove_stack_variable(self, variable_type: str, variable_name: str = "") -> str:
+        """
+        Removes a stack variable and returns the removed variable name
+        """
+        assert len(self._stack_variables[variable_type]) == 1 or variable_name, "Ambiguous replacement of stack variable without name specifier!"
+        removed_var = variable_name
+        if not variable_name:
+            removed_var = self._stack_variables[variable_type][0]
+        if removed_var in self._stack_variable_inits:
+            del self._stack_variable_inits[removed_var]
+        del self._stack_variable_dims[removed_var]
+        self._stack_variables[variable_type].remove(removed_var)
+        return removed_var
+
     def reserve_stack_name(self, variable_type: str) -> str:
         if variable_type not in self._stack_variables:
             self._stack_variables[variable_type] = []
@@ -369,6 +383,7 @@ class TemplateManager:
             return f"{typename} {name}{dims} {init};\n"
         else:
             dims = f"(0:{self._stack_variable_dims[name] - 1})" if self._stack_variable_dims[name] >= 1 else "" # Set array dimension, including explicit starting index!
+            if self._stack_variable_dims[name] == -1: dims = "(:)" # Deferred shape
             init = init.replace("{", "(/").replace("}", "/)")
             type_prefix = f"type({typename})"
             if typename.startswith("int"): type_prefix = "integer"