The old syntax was
@opened("UUID") constraintType
Where constraintType was the right hand side of a conformance requirement.
This would always create an archetype where the interface type was `Self`,
so it couldn't cope with member types of opened existential types.
Member types of opened existential types is now a thing with SE-0309, so
this lack of support prevented writing SIL test cases using this feature.
The new syntax is
@opened("UUID", constraintType) interfaceType
The interfaceType is a type parameter rooted in an implicit `Self`
generic parameter, which is understood to be the underlying type of the
existential.
Fixes rdar://problem/93771238.
The new intrinsic, exposed via static functions on Task<T, Never> and
Task<T, Error> (rethrowing), begins an asynchronous context within a
synchronous caller's context. This is only available for use under the
task-to-thread concurrency model, and even then only under SPI.
This is an incremental improvement of the debug info at a
(hop_to_executor) suspend site.
Before this patch the debug info at the call site would use the
`__swift_suspend_point` function name as the current function after
coro lowering has inlined the thunk.
The proper fix is to rewire the debug info such that the thunk name is
never mentioned rather the current function that suspend site sits in is
used.
Until I have figured out how to do that using the current function name
instead of `__swift_suspend_point` for the thunk is an incremental
improvement in the debug information consumers can observe.
rdar://90859530
The main point of this change is to make sure that a shared function always has a body: both, in the optimizer pipeline and in the swiftmodule file.
This is important because the compiler always needs to emit code for a shared function. Shared functions cannot be referenced from outside the module.
In several corner cases we missed to maintain this invariant which resulted in unresolved-symbol linker errors.
As side-effect of this change we can drop the shared_external SIL linkage and the IsSerializable flag, which simplifies the serialization and linkage concept.
Improvement upon #41645 to emit the async suspend dispatch thunk's debug
info with the `linkageName` of the containing function of the async
await.
rdar://88579737
This is an incremental improvement of the debug info at a suspend apply site.
Before this patch the debug info at the call site would use the
`__swift_suspend_dispatch` function name as the current function after
coro lowering has inlined the thunk.
The proper fix is to rewire the debug info such that the thunk name is
never mentioned rather the current function that suspend site sits in is
used.
Until I have figured out how to do that using the current function name
instead of `__swift_suspend_dispatch.5` for the thunk is an incremental
improvement in the debug information consumers can observe.
rdar://88579737
Generated code has never actually initialized this field, so we
might as well remove it. Doing so mostly doesn't impact the ABI
since we don't store anything for arguments or results in the
context as part of the normal call sequence. We do need to adjust
some of the hard-coded contexts, however, such as continuation
contexts and the statically-sized context for special runtime
async functions.
These were previously disabled due to the UB that caused the tests to
fail. Now that this has been fixed, restore these tests to running
state in line with the other targets.
With PE/COFF, one cannot reference a data symbol directly across the
binary module boundary. Instead, the reference must be indirected
through the Import Address Table (IAT) to allow for position
independence.
When generating a reference to a AsyncFunctionPointer ({i8*, i32}), we
tag the pointer as being indirected by tagging bit 1 (with the
assumption that native alignment will ensure 4/8 byte alignment, freeing
the bottom 2 bits at least for bit-packing). We tweak the
v-table/witness table emission such that all references to the
AsyncFunctionPointer are replaced with the linker synthetic import
symbol with the bit packing:
~~~
.quad __imp_$s1L1CC1yyYaKFTu+1
~~~
rather than
~~~
.quad $s1L1CC1yyYaKFTu
~~~
Upon access of the async function pointer reference, we open-code the
check for the following:
~~~
pointer = (pointer & 1) ? *(void **)(pointer & ~1) : pointer;
~~~
Thanks to @DougGregor for the discussion and the suggestion for the
pointer tagging. Thanks to @aschwaighofer for pointers to the code that
I had missed. Also, thanks to @SeanROlszewski for the original code
sample that led to the reduced test case.
Fixes: SR-15399
If target doesn't support musttail (e.g. WebAssembly), the function
passed to coro.end.async can return control back to the caller.
So the frontend should emit 'ret void' instead of unreachable after the
coro.end.async intrinsic call to allow such situation.
Rather than blanket-disabling concurrency tests when we aren't using a
just-built concurrency library, enable them whenever we have a
suitable concurrency runtime, either just-built, in the OS, or via the
back-deployment libraries.
When build-script is given `--back-deploy-concurrency`, also use that
to build other parts of Swift with the back-deployed versions:
* The compiler allows async and actors to be defined with the
back-deployed availability, e.g., the same as `-Xfrontend
-enable-experimental-back-deploy-concurrency`. (The latter will go
away soon)
* The standard library unit testing framework and distributed actors
library are build with the older OS versions.
* The tests use the older OS versions, with some adjustments to make
them agnostic to the back-deployment setting.
Tracking this as a single bit is actually largely uninteresting
to the runtime. To handle priority escalation properly, we really
need to track this at a finer grain of detail: recording that the
task is running on a specific thread, enqueued on a specific actor,
or so on. But starting by tracking a single bit is important for
two reasons:
- First, it's more realistic about the performance overheads of
tasks: we're going to be doing this tracking eventually, and
the cost of that tracking will be dominated by the atomic
access, so doing that access now sets the baseline about right.
- Second, it ensures that we've actually got runtime involvement
in all the right places to do this tracking.
A propos of the latter: there was no runtime involvement with
awaiting a continuation, which is a point at which the task
potentially transitions from running to suspended. We must do
the tracking as part of this transition, rather than recognizing
in the run-loops that a task is still active and treating it as
having suspended, because the latter point potentially races with
the resumption of the task. To do this, I've had to introduce
a runtime function, swift_continuation_await, to do this awaiting
rather than inlining the atomic operation on the continuation.
As part of doing this work, I've also fixed a bug where we failed
to load-acquire in swift_task_escalate before walking the task
status records to invoke escalation actions.
I've also fixed several places where the handling of task statuses
may have accidentally allowed the task to revert to uncancelled.
Because actors don't have inheritance, ban "open" and "required", which
don't make sense. We will permit "final" which, although it doesn't
have any semantic impact, is still used to determine whether the ABI
of the actor itself might permit subclassing in the future. This
leaves the door slightly ajar for actor inheritance should we need to
revisit that decision.
Fixes SR-14785 / rdar://79401150.
We were not making references to async function pointers "weak" when
the function itself was weak, because we were always calculating
linkage as-if we were defining the async function pointer.
Fixes the rest of rdar://79674106.
Rather than using group task options constructed from the Swift parts
of the _Concurrency library and passed through `createAsyncTask`'s
options, introduce a separate builtin that always takes a group. Move
the responsibility for creating the options structure into IRGen, so
we don't need to expose the TaskGroupTaskOptionRecord type in Swift.
introduce new options parameter to all task spawning
[Concurrency] ABI for asynclet start to accept options
[Concurrency] fix unittest usages of changed task creation ABI
[Concurrency] introduce constants for parameter indexes in ownership
[Concurrency] fix test/SILOptimizer/closure_lifetime_fixup_concurrency.swift
Changes the task, taskGroup, asyncLet wait funtion call ABIs.
To reduce code size pass the context parameters and resumption function
as arguments to the wait function.
This means that the suspend point does not need to store parent context
and resumption to the suspend point's context.
```
void swift_task_future_wait_throwing(
OpaqueValue * result,
SWIFT_ASYNC_CONTEXT AsyncContext *callerContext,
AsyncTask *task,
ThrowingTaskFutureWaitContinuationFunction *resume,
AsyncContext *callContext);
```
The runtime passes the caller context to the resume entry point saving
the load of the parent context in the resumption function.
This patch adds a `Metadata *` field to `GroupImpl`. The await entry
pointer no longer pass the metadata pointer and there is a path through
the runtime where the task future is no longer available.
Introduce a second level of standard substitutions to the mangling,
all of the form `Sc<character>`, and use it to provide standard
substitutions for most of the _Concurrency types.
This is a precursor to rdar://78269642 and a good mangling-size
optimization in its own right.
This commit changes JobFlags storage to be 32bits, but leaves the runtime
API expressed in terms of size_t. This allows us to pack an Id in the
32bits we freed up.
The offset of this Id in the AsyncTask is an ABI constant. This way
introspection tools can extract the currently running task identifier
without any need for special APIs.
Previously, they were storing a low-bit flag that indicated that they
were a default actor. Using an extra inhabitant frees up the low bit
for future use without being conspicuously more expensive to check.
