For `async` function types, an actor constraint can be enforced by the callee by hopping executors,
unlike with `sync` functions, so doesn't need to influence the outward type of the function.
rdar://76248452
Repurpose mangling operator `Y` as an umbrella operator that covers new attributes on function types. Free up operators `J`, `j`, and `k`.
```
async ::= 'Ya' // 'async' annotation on function types
sendable ::= 'Yb' // @Sendable on function types
throws ::= 'K' // 'throws' annotation on function types
differentiable ::= 'Yjf' // @differentiable(_forward) on function type
differentiable ::= 'Yjr' // @differentiable(reverse) on function type
differentiable ::= 'Yjd' // @differentiable on function type
differentiable ::= 'Yjl' // @differentiable(_linear) on function type
```
Resolves rdar://76299796.
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.
My goal was to reduce the size of SILLocation. It now contains only of a storage union, which is basically a pointer and a bitfield containing the Kind, StorageKind and flags. By far, most locations are only single pointers to an AST node. For the few cases where more data needs to be stored, this data is allocated separately: with the SILModule's bump pointer allocator.
While working on this, I couldn't resist to do a major refactoring to simplify the code:
* removed unused stuff
* The term "DebugLoc" was used for 3 completely different things:
- for `struct SILLocation::DebugLoc` -> renamed it to `FilePosition`
- for `hasDebugLoc()`/`getDebugSourceLoc()` -> renamed it to `hasASTNodeForDebugging()`/`getSourceLocForDebugging()`
- for `class SILDebugLocation` -> kept it as it is (though, `SILScopedLocation` would be a better name, IMO)
* made SILLocation more "functional", i.e. replaced some setters with corresponding constructors
* replaced the hand-written bitfield `KindData` with C bitfields
* updated and improved comments
Bridging an async Swift method back to an ObjC completion-handler-based API requires
that the ObjC thunk spawn a task on which to execute the Swift async API and pass
its results back on to the completion handler.
implicitly-async calls are calls to synchronous
actor-isolated functions. Synchronous functions
cannot perform hop_to_executor, so implicitly
async calls have the convention that the caller
is responsible for switching to the right
executor prior to entering the actor-isolated
callee.
It follows naturally that the caller must then
switch back to the appropriate executor after
the implicitly-async call completed.
Now, if the caller is not isolated to a
_specific_ actor, then we are (currently)
_not_ emitting a hop to go back to the
caller's executor, because that caller's
executor is unspecified (and currently not
accessable in SIL). This behavior may change
in the future; tracked in rdar://71905765
So if we use an ObjC imported as async to conform to a Swift protocol, delegate a Swift subclass initializer, etc.,
we generate the conversion thunk to the Swift calling convention for the imported API.
This makes it easier to understand conceptually why a ValueOwnershipKind with
Any ownership is invalid and also allowed me to explicitly document the lattice
that relates ownership constraints/value ownership kinds.
We import a C function taking a non-const pointer 'self' parameter
as a mutating method.
The getParameterTypes() helper method in SILGenBridging.cpp would
assert upon encountering the inout 'self' parameter, even though
emitForeignToNativeThunk() would still emit correct code as long
as the 'self' type was not bridged.
Relax the assertion a bit to hopefully still catch bugs where
other parameters are unexpectedly 'inout', but allow it on 'self',
and add a test.
Fixes <rdar://problem/70346482>.
Allow SILGen to not crash when invoking foreign async methods by emitting
`undef` for the completion callback going into the call, and for the
results that would be channeled back through awaiting the continuation.
This patch includes a large number of changes to make sure that:
1. When ExtInfo values are created, we store a ClangTypeInfo if applicable.
2. We reduce dependence on storing SIL representations in ASTExtInfo values.
3. Reduce places where we sloppily create ASTExtInfo values which should
store a Clang type but don't. In certain places, this is unavoidable;
see [NOTE: ExtInfo-Clang-type-invariant].
Ideally, we would check that the appropriate SILExtInfo does always store
a ClangTypeInfo. However, the presence of the HasClangFunctionTypes option
means that we would need to condition that assertion based on a dynamic check.
Plumbing the setting down to SILExtInfoBuilder's checkInvariants would be too
much work. So we weaken the check for now; we should strengthen it once we
"turn on" HasClangFunctionTypes and remove the dynamic feature switch.
At all call-sites, the extInfo passed as the third argument is computed directly
from the second argument, so we compute it directly in getBridgedFunctionType.
Since the two ExtInfos share a common ClangTypeInfo, and C++ doesn't let us
forward declare nested classes, we need to hoist out AnyFunctionType::ExtInfo
and SILFunctionType::ExtInfo to the top-level.
We also add some convenience APIs on (AST|SIL)ExtInfo for frequently used
withXYZ methods. Note that all non-default construction still goes through the
builder's build() method.
We do not add any checks for invariants here; those will be added later.
```
class Generic<T> {
@objc dynamic func method() {}
}
extension Generic {
@_dynamicReplacement(for:method())
func replacement() {}
}
```
The standard mechanism of using Objective-C categories for dynamically
replacing @objc methods in generic classes does not work.
Instead we mark the native entry point as replaceable.
Because this affects all @objc methods in generic classes (whether there
is a replacement or not) by making the native entry point
`[dynamically_replaceable]` (regardless of optimization mode) we guard this by
the -enable-implicit-dynamic flag because we are late in the release cycle.
* Replace isNativeDynamic and isObjcDynamic by calls to shouldUse*Dispatch and
shouldUse*Replacement
This disambiguates between which dispatch method we should use at call
sites and how these methods should implement dynamic function
replacement.
* Don't emit the method entry for @_dynamicReplacement(for:) of generic class
methods
There is not way to call this entry point since we can't generate an
objective-c category for generic classes.
rdar://63679357
This became necessary after recent function type changes that keep
substituted generic function types abstract even after substitution to
correctly handle automatic opaque result type substitution.
Instead of performing the opaque result type substitution as part of
substituting the generic args the underlying type will now be reified as
part of looking at the parameter/return types which happens as part of
the function convention apis.
rdar://62560867
This fixes an immediate bug with subst-to-orig conversion of
parameter functions that I'm surprised isn't otherwise tested.
More importantly, it preserves valuable information that should
let us handle a much wider variety of variant representations
that aren't necessarily expressed in the AbstractionPattern.
In order to allow this, I've had to rework the syntax of substituted function types; what was previously spelled `<T> in () -> T for <X>` is now spelled `@substituted <T> () -> T for <X>`. I think this is a nice improvement for readability, but it did require me to churn a lot of test cases.
Distinguishing the substitutions has two chief advantages over the existing representation. First, the semantics seem quite a bit clearer at use points; the `implicit` bit was very subtle and not always obvious how to use. More importantly, it allows the expression of generic function types that must satisfy a particular generic abstraction pattern, which was otherwise impossible to express.
As an example of the latter, consider the following protocol conformance:
```
protocol P { func foo() }
struct A<T> : P { func foo() {} }
```
The lowered signature of `P.foo` is `<Self: P> (@in_guaranteed Self) -> ()`. Without this change, the lowered signature of `A.foo`'s witness would be `<T> (@in_guaranteed A<T>) -> ()`, which does not preserve information about the conformance substitution in any useful way. With this change, the lowered signature of this witness could be `<T> @substituted <Self: P> (@in_guaranteed Self) -> () for <A<T>>`, which nicely preserves the exact substitutions which relate the witness to the requirement.
When we adopt this, it will both obviate the need for the special witness-table conformance field in SILFunctionType and make it far simpler for the SILOptimizer to devirtualize witness methods. This patch does not actually take that step, however; it merely makes it possible to do so.
As another piece of unfinished business, while `SILFunctionType::substGenericArgs()` conceptually ought to simply set the given substitutions as the invocation substitutions, that would disturb a number of places that expect that method to produce an unsubstituted type. This patch only set invocation arguments when the generic type is a substituted type, which we currently never produce in type-lowering.
My plan is to start by producing substituted function types for accessors. Accessors are an important case because the coroutine continuation function is essentially an implicit component of the function type which the current substitution rules simply erase the intended abstraction of. They're also used in narrower ways that should exercise less of the optimizer.
Even if differently-substituted function types have different value representations,
we can still share reabstraction and bridging thunks among types that are equivalent after
substitution, so handle these by generating thunks in terms of the unsubstituted type and
converting to the needed substitution form at the use site.
It's possible for a value of a non-trivial type to have no cleanup,
if the value was constructed from a no-payload enum case. Tweak
the assert to check the value's ownership instead of checking the
type.
Fixes <https://bugs.swift.org/browse/SR-12000>, <rdar://problem/58455443>.
All the context dependencies in SIL type lowering have been eradicated, but IRGen's
type info lowering is still context-dependent and doesn't systemically pass generic
contexts around. Sink GenericContextScope bookkeeping entirely into IRGen for now.
ProtocolConformanceRef already has an invalid state. Drop all of the
uses of Optional<ProtocolConformanceRef> and just use
ProtocolConformanceRef::forInvalid() to represent it. Mechanically
translate all of the callers and callsites to use this new
representation.
https://forums.swift.org/t/improving-the-representation-of-polymorphic-interfaces-in-sil-with-substituted-function-types/29711
This prepares SIL to be able to more accurately preserve the calling convention of
polymorphic generic interfaces by letting the type system represent "substituted function types".
We add a couple of fields to SILFunctionType to support this:
- A substitution map, accessed by `getSubstitutions()`, which maps the generic signature
of the function to its concrete implementation. This will allow, for instance, a protocol
witness for a requirement of type `<Self: P> (Self, ...) -> ...` for a concrete conforming
type `Foo` to express its type as `<Self: P> (Self, ...) -> ... for <Foo>`, preserving the relation
to the protocol interface without relying on the pile of hacks that is the `witness_method`
protocol.
- A bool for whether the generic signature of the function is "implied" by the substitutions.
If true, the generic signature isn't really part of the calling convention of the function.
This will allow closure types to distinguish a closure being passed to a generic function, like
`<T, U> in (*T, *U) -> T for <Int, String>`, from the concrete type `(*Int, *String) -> Int`,
which will make it easier for us to differentiate the representation of those as types, for
instance by giving them different pointer authentication discriminators to harden arm64e
code.
This patch is currently NFC, it just introduces the new APIs and takes a first pass at updating
code to use them. Much more work will need to be done once we start exercising these new
fields.
This does bifurcate some existing APIs:
- SILFunctionType now has two accessors to get its generic signature.
`getSubstGenericSignature` gets the generic signature that is used to apply its
substitution map, if any. `getInvocationGenericSignature` gets the generic signature
used to invoke the function at apply sites. These differ if the generic signature is
implied.
- SILParameterInfo and SILResultInfo values carry the unsubstituted types of the parameters
and results of the function. They now have two APIs to get that type. `getInterfaceType`
returns the unsubstituted type of the generic interface, and
`getArgumentType`/`getReturnValueType` produce the substituted type that is used at
apply sites.
Structurally prevent a number of common anti-patterns involving generic
signatures by separating the interface into GenericSignature and the
implementation into GenericSignatureBase. In particular, this allows
the comparison operators to be deleted which forces callers to
canonicalize the signature or ask to compare pointers explicitly.
We've fixed a number of bugs recently where callers did not expect
to get a null Type out of subst(). This occurs particularly often
in SourceKit, where the input AST is often invalid and the types
resulting from substitution are mostly used for display.
Let's fix all these potential problems in one fell swoop by changing
subst() to always return a Type, possibly one containing ErrorTypes.
Only a couple of places depended on the old behavior, and they were
easy enough to change from checking for a null Type to checking if
the result responds with true to hasError().
Also while we're at it, simplify a few call sites of subst().
This allows the conversion of the Windows `BOOL` type to be converted to
`Bool` implicitly. The implicit bridging allows for a more ergonomic
use of the native Windows APIs in Swift.
Due to the ambiguity between the Objective C `BOOL` and the Windows
`BOOL`, we must manually map the `BOOL` type to the appropriate type.
This required lifting the mapping entry for `ObjCBool` from the mapped
types XMACRO definition into the inline definition in the importer.
Take the opportunity to simplify the mapping code.
Adjust the standard library usage of the `BOOL` type which is now
eclipsed by the new `WindowsBool` type, preferring to use `Bool`
whenever possible.
Thanks to Jordan Rose for the suggestion to do this and a couple of
hints along the way.
This was partially implemented but the check looked at the lowered
types and not the AST types, and DynamicSelfType is erased at the
top level of a lowered type.
Also use the new mangling for reabstraction thunks with self, to
ensure we don't emit the same symbol with two different lowered
types.
Fixes <https://bugs.swift.org/browse/SR-10309>, <rdar://problem/49703441>.
OpaqueValueState used to store a SILValue, so back then the IsConsumable flag
was meaningful. But now we can just check if the ManagedValue has a cleanup
or not.
Also, we were passing around an opened ArchetypeType for no good reason.
