IRGen: Only emit resilient tag numbers for resilient enums

[aschwaighofer]

rdar://24057946

[aschwaighofer]

@swift-ci Please test

[slavapestov]

I’m surprised this wasn’t caught by tests - are you sure this whole check isn’t dead somehow?

[slavapestov]

Or can you add IRGen tests ensuring the tag numbers are emitted in the right circumstances?

[aschwaighofer]

I will add positive and negative tests for the globals.

Here is my understanding. Before this commit:
The check if( isResilient(theEnum, ResilienceExpansion::Maximal)) return; -- if this definition is resilient in the local domain was a no-op (as you pointed out) and so we are always emitting globals even for non-resilient enums.

After this commit:
if (!isResilient(theEnum, ResilienceExpansion::Minimal))) return -- if this definition is not resilient in the minimal expansion then we have a fragile enum for which we should not emit a global. (resilient class thunk emission uses the same test)

[aschwaighofer]

@swift-ci Please smoke test

[slavapestov]

Oh you’re absolutely right. Thanks for the explanation. Now I see that only negative tests would’ve caught this (or TBD tests actually, since it’s an error to have an IRGen symbol that’s not in the TBD).

[aschwaighofer]

@swift-ci Please smoke test