Dan Zheng 24445dd2e2 [AutoDiff upstream] Add differentiability witness SILGen. (#30545) ...

Generate SIL differentiability witnesses from `@differentiable` and
`@derivative` declaration attributes.

Add SILGen utilities for:
- Emiting differentiability witnesses.
- Creating derivative function thunks, which are used as entries in
  differentiability witnesses.

When users register a custom derivative function, it is necessary to create a
thunk with the expected derivative type computed from the original function's
type. This is important for consistent typing and consistent differentiability
witness entry mangling.

See `SILGenModule::getOrCreateCustomDerivativeThunk` documentation for details.

Resolves TF-1138.

2020-03-21 02:05:04 -07:00

8.9 KiB

Raw Blame History

View Raw