xref: /llvm-project/mlir/test/python/live_operations.py (revision 67897d77eda4c312cfe81b19a20abed43227ecb8)
1# RUN: %PYTHON %s
2# It is sufficient that this doesn't assert.
3
4from mlir.ir import *
5
6
7def createDetachedModule():
8    module = Module.create()
9    with InsertionPoint(module.body):
10        # TODO: Python bindings are currently unaware that modules are also
11        # operations, so having a module erased won't trigger the cascading
12        # removal of live operations (#93337). Use a non-module operation
13        # instead.
14        nested = Operation.create("test.some_operation", regions=1)
15
16        # When the operation is detached from parent, it is considered to be
17        # owned by Python. It will therefore be erased when the Python object
18        # is destroyed.
19        nested.detach_from_parent()
20
21        # However, we create and maintain references to operations within
22        # `nested`. These references keep the corresponding operations in the
23        # "live" list even if they have been erased in C++, making them
24        # "zombie". If the C++ allocator reuses one of the address previously
25        # used for a now-"zombie" operation, this used to result in an
26        # assertion "cannot create detached operation that already exists" from
27        # the bindings code. Erasing the detached operation should result in
28        # removing all nested operations from the live list.
29        #
30        # Note that the assertion is not guaranteed since it depends on the
31        # behavior of the allocator on the C++ side, so this test mail fail
32        # intermittently.
33        with InsertionPoint(nested.regions[0].blocks.append()):
34            a = [Operation.create("test.some_other_operation") for i in range(100)]
35    return a
36
37
38def createManyDetachedModules():
39    with Context() as ctx, Location.unknown():
40        ctx.allow_unregistered_dialects = True
41        for j in range(100):
42            a = createDetachedModule()
43
44
45if __name__ == "__main__":
46    createManyDetachedModules()
47