This routine takes a synchronous non-throwing main actor isolated closure
without a result. If we are dynamically on the main actor, we just run the
closure synchronously. Otherwise, we run a new task on the main actor and call
the closure on that.
This builds on top of the previous commit by using
swift_task_isCurrentExecutorWithFlags in the implementation of this function.
To backwards deploy this function on Darwin, I used some tricks from libdispatch
to validate that we are on the main queue.
Refactor SILGen's ApplyOptions into an OptionSet, add a
DoesNotAwait flag to go with DoesNotThrow, and sink it
all down into SILInstruction.h.
Then, replace the isNonThrowing() flag in ApplyInst and
BeginApplyInst with getApplyOptions(), and plumb it
through to TryApplyInst as well.
Set the flag when SILGen emits a sync call to a reasync
function.
When set, this disables the SIL verifier check against
calling async functions from sync functions.
Finally, this allows us to add end-to-end tests for
rdar://problem/71098795.
Resilient witness tables and resilient class vtables are built from
descriptors. Make sure we reference the AsyncFunctionPointer of a
method implementation, and not the implementation itself, if the
method is async.
Part of rdar://problem/73625623.
