Fix CUDA extension ninja build (#49344)
Summary:
I am submitting this PR on behalf of Janne Hellsten(nurpax) from NVIDIA, for the convenience of CLA. Thanks Janne a lot for the contribution!
Currently, the ninja build decides whether to rebuild a .cu file or not pretty randomly. And there are actually two issues:
First, the arch list in the building command is ordered randomly. When the order changes, it will unconditionally rebuild regardless of the timestamp.
Second, the header files are not included in the dependency list, so if the header file changes, it is possible that ninja will not rebuild.
This PR fixes both issues. The fix for the second issue requires nvcc >= 10.2. nvcc < 10.2 can still build CUDA extension as it used to be, but it will be unable to see the changes in header files.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49344
Reviewed By: glaringlee
Differential Revision: D25540157
Pulled By: ezyang
fbshipit-source-id: 197541690d7f25e3ac5ebe3188beb1f131a4c51f
