Nate Chandler 4aff98ffb5 [SILGen] Use opaque AP for ObjC-async returns. ...

Previously, the AbstractionPattern that was used for the value
"returned" (i.e. via a completion handler) from ObjC mostly (but not
quite always) was "type".

The generated completion handler correctly (because this is required in
order to call _resumeUnsafeContinuation) reabstracted the block (e.g.
from @convention(block) to @substituted <T> () -> @out T for <()>).  The
callee of the ObjC function, however, loaded the function from the block
as if it were not reabstracted (e.g. () -> ()).

On most platforms, that happened to work.  On arm64e, that difference in
types caused in a difference in pointer signing, resulting in a failure
at runtime.

rdar://85526879
rdar://85526916

2022-04-20 10:42:45 -07:00

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