pytorch

81c7c3ba - Add api.structured; switch structured kernels to use const Tensor& everywhere (#51490)

Add api.structured; switch structured kernels to use const Tensor& everywhere (#51490) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/51490 Mutable Tensor ref is a source of endless confusion for kernel writers; if we're going to make everyone rewrite their kernels, might as well also get rid of mutable Tensor& while we're at it. This is a refactor-then-small-update double whammy. The refactor is to separate tools.codegen.api.structured from api.native for describing the type signatures of structured kernels (previously, I was naughtily reusing native for this purpose--now I need it to behave differently as Tensor). This started off as a copy paste, but since there are not that many structured kernels so far I could delete all of the legacy logic from native that didn't make sense (without having to go out and fix all the use sites all at once). One more small addition was teaching translate to convert Tensor& to const Tensor&. Signed-off-by: Edward Z. Yang <ezyang@fb.com> Test Plan: Imported from OSS Reviewed By: bhosmer Differential Revision: D26182413 Pulled By: ezyang fbshipit-source-id: ed636866add3581179669cf9283f9835fcaddc06