Also, add a third [serializable] state for functions whose bodies we
*can* serialize, but only do so if they're referenced from another
serialized function.
This will be used for bodies synthesized for imported definitions,
such as init(rawValue:), etc, and various thunks, but for now this
change is NFC.
In 74d979f0ac, the policy was changed
so that only value type accessors are ever marked transparent, and
not class accessors.
This was intended to fix a bug where inlining an accessor of an
Objective-C-derived class across module boundaries caused a linker
failure because the accessor referenced a field offset variable,
which has hidden visibility.
However, this also caused a performance regression for Swift native
classes. Bring back the old behavior for Swift native classes in
non-resilient modules.
Fixes <rdar://problem/29884727>.
This will allow for modules to be split from the command line using a script.
The one thing that is missing from this still is that it does not handle shared
functions in IMO a satisfactory way. Given that we are splitting a module, my
feeling that the correct way to do this is to create a public shim for the
shared function in the module that the shared function gets put in and let all
other users use that entry point.
But I need to think about this a bit more.
