Test functionalization pass in python (#66101)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66101
Updated description:
This PR tests the functionalization pass in python in two ways. For each of the test programs that I have in `test_functionalization.py`, it:
- runs the program with and without functionalization, and asserts the outputs and (potentially mutated) inputs are equal in both cases
- runs the program with `LoggingTensor`, and uses expecttests on the resulting graph. I manually confirm that the graphs look reasonable and only contain functional ops.
Mechanically, the changes include:
- factoring out `LoggingTensor` into a testing util so it can be re-used in multiple tests
- adding some private python api's in the `torch` namespace as hooks that I can use during testing
In the original version of this PR, I also added some fixes to the `_make_subclass()` function in python: allowing you to pass in strides and storage_offset. I kept them in mainly because the changes were already there.
Test Plan: Imported from OSS
Reviewed By: zou3519
Differential Revision: D31942095
Pulled By: bdhirsh
fbshipit-source-id: 90ff4c88d461089704922e779571eee09c21d707
