Enable serialization/deserialization of ObjectCode instances (#660)

* implement __reduce__

* updates

* inline function

* fix reduce

* apply patch

* address reviews

---------

Co-authored-by: Ralf W. Grosse-Kunstleve <rwgkio@gmail.com>

Author: brandon-b-miller

cuda_core/cuda/core/experimental/_module.py

@@ -302,6 +302,14 @@ def _init(cls, module, code_type, *, symbol_mapping: Optional[dict] = None):
 
         return self
 
+    @classmethod
+    def _reduce_helper(self, module, code_type, symbol_mapping):
+        # just for forwarding kwargs
+        return ObjectCode._init(module, code_type, symbol_mapping=symbol_mapping)
+
+    def __reduce__(self):
+        return ObjectCode._reduce_helper, (self._module, self._code_type, self._sym_map)
+
     @staticmethod
     def from_cubin(module: Union[bytes, str], *, symbol_mapping: Optional[dict] = None) -> "ObjectCode":
         """Create an :class:`ObjectCode` instance from an existing cubin.

cuda_core/tests/test_module.py

@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import ctypes
+import pickle  # nosec B403, B301
 import warnings
 
 import pytest
@@ -245,3 +246,13 @@ def test_num_args_error_handling(deinit_all_contexts_function, cuda12_prerequisi
     with pytest.raises(CUDAError):
         # assignment resolves linter error "B018: useless expression"
         _ = krn.num_arguments
+
+
+def test_module_serialization_roundtrip(get_saxpy_kernel):
+    _, objcode = get_saxpy_kernel
+    result = pickle.loads(pickle.dumps(objcode))  # nosec B403, B301
+
+    assert isinstance(result, ObjectCode)
+    assert objcode.code == result.code
+    assert objcode._sym_map == result._sym_map
+    assert objcode._code_type == result._code_type