Consider an `@_alwaysEmitIntoClient` function and a custom derivative
defined
for it. Previously, such a combination resulted different errors under
different
circumstances.
Sometimes, there were linker errors due to missing derivative function
symbol -
these occurred when we tried to find the derivative in a module, while
it
should have been emitted into client's code (and it did not happen).
Sometimes, there were SIL verification failures like this:
```
SIL verification failed: internal/private function cannot be serialized or serializable: !F->isAnySerialized() || embedded
```
Linkage and serialization options for the derivative were not handled
properly,
and, instead of PublicNonABI linkage, we had Private one which is
unsupported
for serialization - but we need to serialize `@_alwaysEmitIntoClient`
functions
so the client's code is able to see them.
This patch resolves the issue and adds proper handling of custom
derivatives
of `@_alwaysEmitIntoClient` functions. Note that either both the
function and
its custom derivative or none of them should have
`@_alwaysEmitIntoClient`
attribute, mismatch in this attribute is not supported.
The following cases are handled (assume that in each case client's code
uses
the derivative).
1. Both the function and its derivative are defined in a single file in
one module.
2. Both the function and its derivative are defined in different files
which
are compiled to a single module.
3. The function is defined in one module, its derivative is defined in
another
module.
4. The function and the derivative are defined as members of a protocol
extension in two separate modules - one for the function and one for the
derivative. A struct conforming the protocol is defined in the third
module.
5. The function and the derivative are defined as members of a struct
extension in two separate modules - one for the function and one for the
derivative.
The changes allow to define derivatives for methods of `SIMD`.
Fixes#54445
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Store specialize witness tables in a separate lookup table in the module. This allows that for a normal conformance there can exist the original _and_ a specialized witness table.
Also, add a boolean property `isSpecialized` to `WitnessTable` which indicates whether the witness table is specialized or not.
In embedded swift all the code is generated in the top-level module.
De-serialized witness tables for class existentials must be code-gen'd and therefore made non-external.
Fixes an unresolved symbol linker error.
rdar://142561676
The main change here is to associate a witness table with a `ProtocolConformance` instead of a `RootProtocolConformance`.
A `ProtocolConformance` is the base class and can be a `RootProtocolConformance` or a `SpecializedProtocolConformance`.
- Keep witness thunk linkage private for a package protocol member in SILGen.
- Optimize private/hidden functions during Package CMO; if they don't contain
references that have private/hidden symbols, serialize them and set the linkage
to shared. For unserialized witness thunks, set the linkage to package, so the
witness table itself can be serialized.
- Update witness table and vtable serialization.
Resolves rdar://129976582
Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
inlining, generic/closure specialization, and devirtualization optimization passes.
SILFunction::canBeInlinedIntoCaller now exlicitly requires a caller's SerializedKind_t arg.
isAnySerialized() is added as a convenience function that checks if [serialized] or [serialized_for_pkg].
Resolves rdar://128704752
[serialized_for_package] if Package CMO is enabled. The latter kind
allows a function to be serialized even if it contains loadable types,
if Package CMO is enabled. Renamed IsSerialized_t as SerializedKind_t.
The tri-state serialization kind requires validating inlinability
depending on the serialization kinds of callee vs caller; e.g. if the
callee is [serialized_for_package], the caller must be _not_ [serialized].
Renamed `hasValidLinkageForFragileInline` as `canBeInlinedIntoCaller`
that takes in its caller's SerializedKind as an argument. Another argument
`assumeFragileCaller` is also added to ensure that the calle sites of
this function know the caller is serialized unless it's called for SIL
inlining optimization passes.
The [serialized_for_package] attribute is allowed for SIL function, global var,
v-table, and witness-table.
Resolves rdar://128406520
In embedded swift all de-serialized get public linkage because all the code is generated in the top-level module.
This change moves the point where we make de-serialized functions public to the end of the pipeline.
This allows dead function elimination to remove unused de-serialized functions.
For some stdlib functions (actually one: the Double initializer for a builtin integer) is essential, because codegen for embedded produces an unresolved symbol.
rdar://123772098
When an actual instance of a distributed actor is on the local node, it is
has the capabilities of `Actor`. This isn't expressible directly in the type
system, because not all `DistributedActor`s are `Actor`s, nor is the
opposite true.
Instead, provide an API `DistributedActor.asLocalActor` that can only
be executed when the distributed actor is known to be local (because
this API is not itself `distributed`), and produces an existential
`any Actor` referencing that actor. The resulting existential value
carries with it a special witness table that adapts any type
conforming to the DistributedActor protocol into a type that conforms
to the Actor protocol. It is "as if" one had written something like this:
extension DistributedActor: Actor { }
which, of course, is not permitted in the language. Nonetheless, we
lovingly craft such a witness table:
* The "type" being extended is represented as an extension context,
rather than as a type context. This hasn't been done before, all Swift
runtimes support it uniformly.
* A special witness is provided in the Distributed library to implement
the `Actor.unownedExecutor` operation. This witness back-deploys to the
Swift version were distributed actors were introduced (5.7). On Swift
5.9 runtimes (and newer), it will use
`DistributedActor.unownedExecutor` to support custom executors.
* The conformance of `Self: DistributedActor` is represented as a
conditional requirement, which gets satisfied by the witness table
that makes the type a `DistributedActor`. This makes the special
witness work.
* The witness table is *not* visible via any of the normal runtime
lookup tables, because doing so would allow any
`DistributedActor`-conforming type to conform to `Actor`, which would
break the safety model.
* The witness table is emitted on demand in any client that needs it.
In back-deployment configurations, there may be several witness tables
for the same concrete distributed actor conforming to `Actor`.
However, this duplication can only be observed under fairly extreme
circumstances (where one is opening the returned existential and
instantiating generic types with the distributed actor type as an
`Actor`, then performing dynamic type equivalence checks), and will
not be present with a new Swift runtime.
All of these tricks together mean that we need no runtime changes, and
`asLocalActor` back-deploys as far as distributed actors, allowing it's
use in `#isolation` and the async for...in loop.
The SIL linker de-serializes functions. Immediately after de-serialization some `[serialized]` flags of referenced functions may not be set correctly, yet.
This is fixed by the linker. But it also means that the SIL is only valid after the linker has finished processing all functions.
Fixes a SIL verifier error.
- Add a flag to the serialized module (IsEmbeddedSwiftModule)
- Check on import that the mode matches (don't allow importing non-embedded module in embedded mode and vice versa)
- Drop TBD support, it's not expected to work in embedded Swift for now
- Drop auto-linking backdeploy libraries, it's not expected to backdeploy embedded Swift for now
- Drop prespecializations, not expected to work in embedded Swift for now
- Use CMO to serialize everything when emitting an embedded Swift module
- Change SILLinker to deserialize/import everything when importing an embedded Swift module
- Add an IR test for importing modules
- Add a deserialization validation test
Include the parent `ModuleDecl` when serializing a `SILFunction` so that it is available on deserialized functions even though the full `DeclContext` is not present. With the parent module always available we can reliably compute whether the `SILFunction` comes from a module that was imported `@_weakLinked`.
Serialize the `DeclContext` member of `SILFunction` so that it can be used to look up the module that a function belongs to in order to compute weak import status.
Resolves rdar://98521248
We never have them, we never need them, and we'll crash if there were
one for a conformance of a non-nominal type to such a protocol.
Fixes rdar://91126885 .
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.
Reduces the number of _ContiguousArrayStorage metadata.
In order to support constant time bridging we do need to set the correct
metadata when we bridge to Objective-C. This is so that the type check
succeeds when bridging back from Objective-C to reuse the storage
instance rather than bridging the elements.
To support dynamically setting the `_ContiguousArrayStorage` element
type i needed to add support for optimizing `alloc_ref_dynamic`
throughout the optimizer.
Possible future improvements:
* Use different metadata such that we can disambiguate native Swift
classes during destruction -- allowing native release rather then unknown
release usage.
* Optimize the newly added semantic function
getContiguousArrayStorageType
rdar://86171143
If we know that we have a FunctionRefInst (and not another variant of FunctionRefBaseInst), we know that getting the referenced function will not be null (in contrast to FunctionRefBaseInst::getReferencedFunctionOrNull).
NFC
Specifically, I split it into 3 initial categories: IR, Utils, Verifier. I just
did this quickly, we can always split it more later if we want.
I followed the model that we use in SILOptimizer: ./lib/SIL/CMakeLists.txt vends
a macro (sil_register_sources) to the sub-folders that register the sources of
the subdirectory with a global state variable that ./lib/SIL/CMakeLists.txt
defines. Then after including those subdirs, the parent cmake declares the SIL
library. So the output is the same, but we have the flexibility of having
subdirectories to categorize source files.
