I am going to be using in inst-simplify/sil-combine/canonicalize instruction a
RAUW everything against everything API (*). This creates some extra ARC
traffic/borrows. It is going to be useful to have some simple peepholes that
gets rid of some of the extraneous traffic.
(*) Noting that we are not going to support replacing non-trivial
OwnershipKind::None values with non-trivial OwnershipKind::* values. This is a
corner case that only comes up with non-trivial enums that have a non-payloaded
or trivial enum case. It is much more complex to implement that transform, but
it is an edge case, so we are just not going to support those for now.
----
I also eliminated the dependence of SILGenCleanup on Swift/SwiftShims. This
speeds up iterating on the test case with a debug compiler since we don't need
those modules.
* Remove RegisterPreservingCC. It was unused.
* Remove DefaultCC from the runtime. The distinction between C_CC and DefaultCC
was unused and inconsistently applied. Separate C_CC and DefaultCC are
still present in the compiler.
* Remove function pointer indirection from runtime functions except those
that are used by Instruments. The remaining Instruments interface is
expected to change later due to function pointer liability.
* Remove swift_rt_ wrappers. Function pointers are an ABI liability that we
don't want, and there are better ways to get nonlazy binding if we need it.
The fully custom wrappers were only needed for RegisterPreservingCC and
for optimizing the Instruments function pointers.
This is different from swift_deallocObject in that it applies to objects
at +1 while swift_deallocObject actually only applies to objects whose
state is deiniting (swift_release was called).
When a boxed type is destroyed, ensure that the object is marked as
deiniting first. This was caught by an assertion in the runtime.
Addresses SR-6268!
