Package config/template files with torchgen (#78942) (#79123)
Package config/template files with torchgen
This PR packages native_functions.yaml, tags.yaml and ATen/templates
with torchgen.
This PR:
- adds a step to setup.py to copy the relevant files over into torchgen
- adds a docstring for torchgen (so `import torchgen; help(torchgen)`
says something)
- adds a helper function in torchgen so you can get the torchgen root
directory (and figure out where the packaged files are)
- changes some scripts to explicitly pass the location of torchgen,
which will be helpful for the first item in the Future section.
Future
======
- torchgen, when invoked from the command line, should use sources
in torchgen/packaged instead of aten/src. I'm unable to do this because
people (aka PyTorch CI) invokes `python -m torchgen.gen` without
installing torchgen.
- the source of truth for all of these files should be in torchgen.
This is a bit annoying to execute on due to potential merge conflicts
and dealing with merge systems
- CI and testing. The way things are set up right now is really fragile,
we should have a CI job for torchgen.
Test Plan
=========
I ran the following locally:
```
python -m torchgen.gen -s torchgen/packaged
```
and verified that it outputted files.
Furthermore, I did a setup.py install and checked that the files are
actually being packaged with torchgen.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/78942
Approved by: https://github.com/ezyang
