Introduce a new runtime entry point,
`swift_objc_swift3ImplicitObjCEntrypoint`, which is called from any
Objective-C method that was generated due to `@objc` inference rules
that were removed by SE-0160. Aside from being a central place where
users can set a breakpoint to catch when this occurs, this operation
provides logging capabilities that can be enabled by setting the
environment variable SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT:
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=0 (default): do not log
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=1: log failed messages
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=2: log failed messages with
backtrace
SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT=3: log failed messages with
backtrace and abort the process.
The log messages look something like:
***Swift runtime: entrypoint -[t.MyClass foo] generated by
implicit @objc inference is deprecated and will be removed in
Swift 4
...and IRGen it into a call to __tsan_write1 in compiler-rt. This is
preparatory work for a later patch that will add an experimental
option to treat Swift inout accesses as TSan writes.
While invoking the instrprof_increment intrinsic, we used to pass the
profile name variable by using a GEP instruction to get to the string
constant. That prevented llvm from uniquing the names. Use a constexpr
GEP to fix the issue.
SubstitutionList is going to be a more compact representation of
a SubstitutionMap, suitable for inline allocation inside another
object.
For now, it's just a typedef for ArrayRef<Substitution>.
We need the encode string to be able to construct NSValues using the core valueWithBytes:objCType: API. This builtin only works with concrete, @objc-representable types for now, which should be sufficient for a stdlib-internal API.
