Implement IRParser. (#16987)
Summary:
It might need some cleaning up and might be missing some features, but it should be already working for most cases.
This PR is based on top of PR16986 (so please review only the last commit here).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16987
Differential Revision: D14074577
Pulled By: ZolotukhinM
fbshipit-source-id: 712b598f423265655f574bb9903e2066628eaad3
Author
Mikhail Zolotukhin
