Module coroutine

Coroutine layout logic.

When laying out coroutines, we divide our saved local fields into two categories: overlap-eligible and overlap-ineligible.

Those fields which are ineligible for overlap go in a “prefix” at the beginning of the layout, and always have space reserved for them.

Overlap-eligible fields are only assigned to one variant, so we lay those fields out for each variant and put them right after the prefix.

Finally, in the layout details, we point to the fields from the variants they are assigned to. It is possible for some fields to be included in multiple variants. No field ever “moves around” in the layout; its offset is always the same.

Also included in the layout are the upvars and the discriminant. These are included as fields on the “outer” layout; they are not part of any variant.

Enums

SavedLocalEligibility 🔒

Overlap eligibility and variant assignment for each CoroutineSavedLocal.

Functions

coroutine_saved_local_eligibility 🔒

Compute the eligibility and assignment of each local.

layout 🔒

Compute the full coroutine layout.