types: Add is_CompositeObject to handle dereferencing petscstruct types

Author: ZoeLeibowitz

devito/ir/iet/visitors.py

@@ -515,20 +515,20 @@ def visit_PointerCast(self, o):
 
     def visit_Dereference(self, o):
         a0, a1 = o.functions
-        # TODO: Temporary fix or fine? — ensures that all objects dereferenced from
-        # a PETSc struct (e.g., `ctx0`) are handled correctly.
+        # TODO: Potentially reconsider — the `if a1.is_CompositeObject`
+        # ensures that all objects dereferenced from a PETSc struct
+        # (e.g., `ctx0`) are handled correctly.
         # **Example**
         # Need this: struct dataobj *rhs_vec = ctx0->rhs_vec;
         # Not this: PetscScalar (* rhs)[rhs_vec->size[1]] =
         # (PetscScalar (*)[rhs_vec->size[1]]) ctx0;
-        # This is the case when a1 is a LocalCompositeObject (i.e a1.is_AbstractObject)
 
         if o.offset:
             ptr = f'({a1.name} + {o.offset})'
         else:
             ptr = a1.name
 
-        if a1.is_AbstractObject:
+        if a1.is_CompositeObject:
             rvalue = f'{a1.name}->{a0._C_name}'
             lvalue = self._gen_value(a0, 0)
         elif a0.is_AbstractFunction:

devito/types/basic.py

@@ -296,6 +296,7 @@ class Basic(CodeSymbol):
     is_ObjectArray = False
     is_Bundle = False
     is_Object = False
+    is_CompositeObject = False
     is_LocalObject = False
     is_LocalType = False
 

devito/types/object.py

@@ -132,6 +132,7 @@ class CompositeObject(Object):
     """
     Object with composite type (e.g., a C struct) defined in Python.
     """
+    is_CompositeObject = True
 
     __rargs__ = ('name', 'pname', 'pfields')