- Emit a withoutActuallyEscapingClosure partial apply
This is to convert an @noescape closure to an escaping closure.
This needs to be done in preparation of @noescape closure contexts
becoming trivial.
- Insert escaping to noescape conversions
- Fix SILGen for @noescape
- Postpone closure cleanups to outside the argument scope
- Apply postponement recursively for closures passed to subscripts
- Only skip applying escapeness conversions for Swift thick functions
- Fix parameter convention for noescape closures in thunks
Part of:
SR-5441
rdar://36116691
Emit a borrow scope whenever exploding tuples in to a list of arguments.
I spent a lot of time attempting to refactor the reabstraction thunk generation
code with code that handles RValue. However, there is a subtle difference in how
tuples are handled when they are packed into a single "RValue" as opposed to a
list of arguments.
Eventually, I ditched that effort because of subtle complexity and fell back on
Michael's suggestion of handling the extra thunk-sepcific work inside
Scope.popPreservingValues. This will just go away though once we have the
'destructure' instruction.
It is only safe to perform a destroy_value on an alloc_box that contains an
initialized value. We preserve the original cleanups for the value we are
pushing through the scope implying that the box will not contain an initialized
value when its lifetime ends (just like an alloc_stack). Thus we must use
dealloc_box here.
The surprising thing about tracking down this error is that I was not hitting
any memory issues at -Onone. Instead what was happening was that at -O, we were
miscompiling (creating non-dominating uses of SSA values) in the face of an
address being taken twice.
This does not seem to hit any SILGen tests today (I hit this when testing a
patch I am trying to land today).
rdar://31521023
