If the preloaded status is locked, then we need to reload it in order to distinguish between the current thread holding the lock and another thread holding the lock. Without this, if another thread holds the lock, then we won't set the is-locked bit. We'll still actually hold the lock, but other threads may perform operations locklessly if the bit is not set, which can cause a crash. By reloading status in that case, we ensure that the bit is always set correctly.
This manifested as crashes in task cancellation but could cause other task-related issues as well.
Also remove an assert of !isStatusRecordLocked() in AsyncTask::complete(). We allow other threads to access tasks and take the lock for things like cancellation, so the lock may legitimately be held at that point.
rdar://150327908
We were failing to switch executors to Dispatch queues, where those
were being used as executors, which caused a variety of unusual
symptoms.
rdar://150310927
This changes the isIsolatingCurrentContext function to return `Bool?`
and removes all the witness table trickery we did previously to detect
if it was implemented or not. This comes at a cost of trying to invoke
it always, before `checkIsolated`, but it makes for an simpler
implementation and more checkable even by third party Swift code which
may want to ask this question.
Along with the `withSerialExecutor` function, this now enables us to
check the isolation at runtime when we have an `any Actor` e.g. from
`#isolation`.
Updates SE-0471 according to
https://forums.swift.org/t/se-0471-improved-custom-serialexecutor-isolation-checking-for-concurrency-runtime/78834/
review discussions
We had fixed this bug in https://github.com/swiftlang/swift/pull/79381
but missed to realize the same problem existed for parameters as well.
This corrects the swift_func_getParameterTypeInfo impl, and also removes
the entire "unsafe" method, we no longer use it anywhere.
Resolves rdar://146679254
The implementation previously took advantage of a missing diagnostic. They
returned a borrowed Span with a dependency on a copied argument. This illegally
promotes the dependency. This is what the author intended to do (the
implementation was correct) but the compiler can't know that so the code needs
to be explicit about overriding the lifetime.
This is basically the same as the one for Linux, but it would be
somewhat awkward to add the platform conditional on a file named for
Linux when OpenBSD is not Linux.
Important note: if Dispatch is disabled, then this will cause a
compilation error (probably not just for OpenBSD either), because
PlatformExecutorFactory is both defined in PlatformExecutorNone.swift
and PlatformExecutor<...>.swift in this case.
Because this only bites OpenBSD bootstrap builds, and since OpenBSD
support has been upstreamed to Dispatch, default to the Dispatch
implementation for now to get this in, and we'll refactor in a different
pr.
The "was already deallocated" message is incorrect, since the target of an unowned reference stays allocated even after being deinitialized. We could say "was already deinitialized" but that's a bit of a niche term. "Was already destroyed" conveys what happened without the reader needing to worry about deinitialization versus deallocation.
rdar://149237704
The new build system set `SWIFT_RUNTIME_CLOBBER_FREED_OBJECTS` to 0.
Unfortunately, the check in the Swift runtime used `#ifdef`, so even
though it was turned off, it was actually enabled in some cases.
Fixing the issue in the build system as well as switching the check to
verify that value of `SWIFT_RUNTIME_CLOBBER_FREED_OBJECTS` is taken into
account in the sources. C/C++ implicitly defines macro values to 1 when
set without a value and 0 when it is not set.
Also making the hex a bit more recognizable and grep'able by including
it as a comment.
Fixes: rdar://149210738
The pass that annotated control-flow positions unreachable after an
infinite loop was migrated to pure Swift in PR 79186
(https://github.com/swiftlang/swift/pull/79186). As a result, the
C++-only bootstrap compiler is unable to determine that the
code-location is unreachable. Placing a fatalError after the infinite
while loop.
Fixes: rdar://149631113
