patterns) in argument positions in reabstraction thunks.
Most of the difficulty in this work continues to center around
(1) trying to reuse as much code as possible between the parameter
and result paths and (2) propagating ownership information as
necessary throughout the code. I did my best to assert the preconditions
and postconditions here, but undoubtedly I'm missing cases. Some
simplicity here is still eluding me here.
This patch necessarily changes quite a bit of the code used in
non-variadic paths. I tried to avoid doing things that I knew would
be risky, like optimizing copies. I did fail in a few places: e.g.
we should now generate significantly better code when erasing to
Optional<Any>, just because the code was oddly poorly-factored before.
You can see the effect on the function_conversion test case.
The `_diagnoseUnavailableCodeReached()` function was introduced in the Swift
5.9 standard library and employs `@backDeployed` to support compilation of
binaries that target OS releases aligned with earlier Swift releases.
Unfortunately, though, this backdeployment strategy doesn't work well for some
unusual build environments. Specifically, in some configurations code may be
built with a compiler from a recent Swift toolchain and then linked against the
dylibs in an older toolchain. When linking against the older dylibs, the
`_diagnoseUnavailableCodeReached()` function does not exist but the
`@backDeployed` thunks emitted into the binary reference that function and
therefore linking fails.
The idea of building with one toolchain and then linking to the dylibs in a
different, older toolchain is extremely dubious. However, it exists and for now
we need to support it. This PR introduces an alternative
`_diagnoseUnavailableCodeReached()` function that is annotated with
`@_alwaysEmitIntoClient`. Calls to the AEIC variant are now emitted by the
compiler when the deployment target is before Swift 5.9.
Once these unusual build environments upgrade and start linking against a Swift
5.9 toolchain or later we can revert all of this.
Resolves rdar://119046537
For an isolated ObjC function that is not async, we
emit a hops around the call. But if that function
returns an autoreleased pointer, we need to ensure
we're retaining that pointer before hopping back
after the call. We weren't doing that in the case
of an autoreleased NSError:
```
%10 = alloc_stack $@sil_unmanaged Optional<NSError>
%19 = ... a bunch of steps to wrap up %10 ...
%20 = enum $Optional<AutoreleasingUnsafeMutablePointer<Optional<NSError>>>, #Optional.some!enumelt, %19 : $AutoreleasingUnsafeMutablePointer<Optional<NSError>>
hop_to_executor $MainActor
%26 = apply X(Y, %20) : $@convention(objc_method) (NSObject, Optional<AutoreleasingUnsafeMutablePointer<Optional<NSError>>>) -> @autoreleased Optional<NSString>
hop_to_executor $Optional<Builtin.Executor>
// retain the autoreleased pointer written-out.
%28 = load [trivial] %10 : $*@sil_unmanaged Optional<NSError>
%29 = unmanaged_to_ref %28 : $@sil_unmanaged Optional<NSError> to $Optional<NSError>
%30 = copy_value %29 : $Optional<NSError>
assign %31 to %7 : $*Optional<NSError>
```
This patch sinks the hop emission after the call
so it happens after doing that copy.
rdar://114049646
Mark the result of a move-only addressor as unresolved. The pointed-at value
cannot be consumed so ensure that only [read] or [modify] accesses are
performed. Update the move-only checker to recognize code patterns
from addressors.
SILGen and IRGen would disagree on the return type of the
`swift_task_getMainExecutor()` runtime function if
`SILGenModule::getGetMainExecutor()` had ever been called. To address this,
consistently use the `buildMainActorExecutorRef` built-in and get rid of
`SILGenModule::getGetMainExecutor()`.
Resolves rdar://116472583
Correctly determining the DeclContext needed for an
ExplicitCaughtTypeRequest is tricky for a number of callers, and
mistakes here can easily lead to redundant computation of the caught
type, redundant diagnostics, etc.
Instead, put a `DeclContext` into `DoCatchStmt`, because that's the
only catch node that needs a `DeclContext` but does not have one.
Following https://github.com/apple/swift/pull/70333, do the same thing for
modify coroutines, marking the result so that we check uses of the result to
ensure it isn't consumed (without being reinitialized).
Mark the result of starting a read coroutine to be checked by the move-only checker, and then
update the pattern matching in the move checker itself so that it recognizes code patterns
involving yielding from and receiving yields from read coroutines. Teach move only diagnostics
to get the property name for an access through a read coroutine from the referenced declaration.
When `-experimental-skip-non-exportable-decls` is specified, skip emitting
property wrapper backing inits since they cannot be referenced directly by
module clients.
Resolves rdar://119469651
