Long term I would like to get region analysis and transfer non sendable out of
the business of directly interpreting the AST... but if we have to do it now, I
would rather us do it through a helper struct. At least the helper struct can be
modified later to work with additional SIL concurrency support when it is added.
This is in preparation for beginning to track an IsolationRegionInfo in
TransferringOperand.
Just splitting this into a separate commit to make it easier to read.
I need to start tracking the dynamic IsolationRegionInfo for the transferring
operand so I can ignore uses that are part of the same
IsolationRegionInfo. IsolationRegionInfo doesn't fit into a pointer, so just to
keep things the same, I am going to just allocate it.
This is an initial staging commit that tests out the bump ptr allocating without
expanding the type yet.
Enable KeyPath/AnyKeyPath/PartialKeyPath/WritableKeyPath in Embedded Swift, but
for compile-time use only:
- Add keypath optimizations into the mandatory optimizations pipeline
- Allow keypath optimizations to look through begin_borrow, to make them work
even in OSSA.
- If a use of a KeyPath doesn't optimize away, diagnose in PerformanceDiagnostics
- Make UnsafePointer.pointer(to:) transparent to allow the keypath optimization
to happen in the callers of UnsafePointer.pointer(to:).
I also eliminated the very basic "why is this task isolated" part of the warning
in favor of the larger, better, region history impl that I am going to land
soon. The diagnostic wasn't that good in the first place and also was fiddly. So
I removed it for now.
rdar://124960994
I am going to need this so that I can use it when evaluating partition
ops. Specifically, so I can when I find two values that do not merge correctly,
emit an error.
Now that we actually know the region that non transferrable things belong to, we
can use this information to give a better diagnostic here.
A really nice effect of this is that we now emit that actor isolated parameters
are actually actor isolated instead of task isolated.
In a subsequent commit, this is going to let me begin handling parameters with
actor regions in a nice way (and standardize all of the errors).
This is meant to be a refactoring commit that uses the current tests in tree to
make sure I did it correctly, so no tests need to be updated.
A destroy_value of Optional.none can be deleted.
A move-only struct with deinit has a non trivial SILType but OwnershipKind::None,
such values cannot be deleted.
For years, optimizer engineers have been hitting a common bug caused by passes
assuming all SILValues have a parent function only to be surprised by SILUndef.
Generally we see SILUndef not that often so we see this come up later in
testing. This patch eliminates that problem by making SILUndef uniqued at the
function level instead of the module level. This ensures that it makes sense for
SILUndef to have a parent function, eliminating this possibility since we can
define an API to get its parent function.
rdar://123484595
I am going to reuse this for TransferNonSendable. In the process I made a few
changes to make it more amenable to both use cases and used the current set of
tests that we have for noncopyable types to validate that I didn't break
anything.
This involved fixing a few different bugs.
1. We were just performing dataflow by setting that only the initial block needs
to be updated. This means that if there isn’t anything in the initial dataflow
block, we won’t visit any successor blocks. Instead the correct thing to do here
is to visit all blocks in the initial round.
2. I also needed to fix a separate issue where we were updating our union-find
data structure incorrectly as found by an assert on transfernonsendable.swift
that was triggered once I fixed 1. Put simply, we needed to set a new max label
+ 1 when our new max element is less than or equal to the old max label + 1…
before we just did less than so if we had a new max element that is the same as
our fresh label, we wouldn’t increment the fresh label.
rdar://119584497
* [SILOpt] Allow pre-specializations for _Trivial of known size
rdar://119224542
This allows pre-specializations to be generated and applied for trivial types of a shared size.
I left them as friends since that was in the original code. There isn't a reason
to do this and break the encapsulation of Partition. I just added reasonable
helpers that give PartitionOpEvaluator all of the functionality it needs.
Previously I avoided doing this since the only problem would be that in a case
where we had two transfer instructions that were in an if-else block, we would
just emit an error for one:
```swift
if boolValue {
transfer(x)
} else {
transfer(x) // Only emit error for this transfer!
}
useValue(x)
```
Now that we are tracking at the transfer point if any element in the transfer
was captured in a closure, this becomes an actual semantic issue since if we
track the transfer instruction that isn't reachable from the closure capture, we
will not become more pessimistic:
```swift
if boolValue {
closure = { useInOut(&x) }
transfer(x)
} else {
transfer(x)
}
// Since we grab from the else block, sendableField is allowed to be accessed
// since we do not track that x was captured by reference in a closure.
x.sendableField
useValue(x)
```
To be truly safe, we need to emit both errors.
rdar://119048779
If the var is captured in a closure before it is transferred, it is not safe to
access the Sendable field since we may race on accessing the field with an
assignment to the field in another concurrency domain.
rdar://115124361
I am not sure if this would ever actually ever cause a bug... but we should be
consistent. The issue here is that in the evaluator switch when processing
transfers in certain cases when we emitted an early error due to an actor
derived value we were performing a transfer and other times we weren't. With
this patch:
1. We now consistently do not actually transfer the value if it is actor
derived. It is always illegal to transfer an actor derived value... so we know
that if we always just error on transferring it, we have a safe model.
2. The switch we breaking so that we could do an assert that we canonicalized
the modified PartitionOp. Rather than do that and allow for people to
potentially return, I moved the assert into a SWIFT_DEFER and added an assert in
the continuation of the switch. This means that if an author ever breaks out of
the switch, they will hit the assert implying that the author in all cases must
explicitly return within the case statement guaranteeing this mistake does not
happen again.
Specifically:
1. If the value is transferred such that it becomes part of an actor region, the
value is permanently part of the actor region as one would normally have.
2. If the value is just used in an async let or is used by a nonisolated async
function within the async let then while the async let is alive it cannot be
used. But once the async let has been awaited upon, we allow for it to be used
again.
rdar://117506395
This means to support specializing functions with indirect error results.
Also, when specializing (and the concrete error type is loadable), convert the indirect error to a direct error.
rdar://118532113
[region-isolation] Since we now propagate the transferred instruction, use that to emit the error instead of attempting to infer the transfer instruction for a requires
