Many, many, many types in the Swift compiler are intended to only be allocated in the ASTContext. We have previously implemented this by writing several `operator new` and `operator delete` implementations into these types. Factor those out into a new base class instead.
Start treating the null {Can}GenericSignature as a regular signature
with no requirements and no parameters. This not only makes for a much
safer abstraction, but allows us to simplify a lot of the clients of
GenericSignature that would previously have to check for null before
using the abstraction.
If a conformance is found in an imported module as well as the current module,
and one of the two conformances is conditionally unavailable on the current
deployment target, pick the one that is always available.
Fixes <rdar://problem/78633800>.
getParsedMembers() on imported and deserialized contexts has to pull
in all the members. This is wasteful. Imported contexts do not have
fingerprints at all, and fingerprints of deserialized contexts are
serialized separately.
The fast path handles these cases, only calling down to
getParsedMembers() if the parent FileUnit is a SourceFile.
When an extension is nested inside of an invalid decl context, it is
going to pull the signature of its nearest enclosing context instead of
its extended type. This leads to a null signature since the nearest
enclosing context for an extension should always be its parent source
file.
rdar://76049852
Introduce an "all members" request to compute all of the members of a
given iterable declaration context in stable order. This builds on ABI
members so that it will also include, e.g., type aliases synthesized
for associated types.
The "semantic members" query produces the list of members that can
affect the ABI, e.g., of classes. It does not produce the complete
list of members suitable for semantic queries.
getFragileFunctionKind() would report that all initializers in
non-resilient public types were inlinable, including static
properties.
This was later patched by VarDecl::isInitExposedToClients(),
which was checked in diagnoseInlinableDeclRefAccess().
However, the latter function only looked at the innermost
DeclContexts, not all parent contexts, so it would incorrectly
diagnose code with a nested DeclContext inside of a static
property initializer.
Fix this by changing getFragileFunctionKind() to call
isInitExposedToClients() and simplifying
diagnoseInlinableDeclRefAccess().
This commit also introduces a new isLayoutExposedToClients()
method, which is similar to isInitExposedToClients(), except
it also returns 'true' if the property does not have an
initializer (and in fact the latter is implemented in terms
of the former).
This attribute allows to define a pre-specialized entry point of a
generic function in a library.
The following definition provides a pre-specialized entry point for
`genericFunc(_:)` for the parameter type `Int` that clients of the
library can call.
```
@_specialize(exported: true, where T == Int)
public func genericFunc<T>(_ t: T) { ... }
```
Pre-specializations of internal `@inlinable` functions are allowed.
```
@usableFromInline
internal struct GenericThing<T> {
@_specialize(exported: true, where T == Int)
@inlinable
internal func genericMethod(_ t: T) {
}
}
```
There is syntax to pre-specialize a method from a different module.
```
import ModuleDefiningGenericFunc
@_specialize(exported: true, target: genericFunc(_:), where T == Double)
func prespecialize_genericFunc(_ t: T) { fatalError("dont call") }
```
Specially marked extensions allow for pre-specialization of internal
methods accross module boundries (respecting `@inlinable` and
`@usableFromInline`).
```
import ModuleDefiningGenericThing
public struct Something {}
@_specializeExtension
extension GenericThing {
@_specialize(exported: true, target: genericMethod(_:), where T == Something)
func prespecialize_genericMethod(_ t: T) { fatalError("dont call") }
}
```
rdar://64993425
Provide an accessor for retrieving the parsed members, generalizing
`ParseMembersRequest` so it can provide the parsed members for
deserialized/synthesized declarations as well. This is the counterpart
to the recently-generalized `getSemanticMembers()`; together, these
should suffice for most (all?) clients of `getMembers()`.
Generalize `ClassDecl::getEmittedMembers()` to operate on an
`IterableDeclContext`, so that it can be for other nominal types,
extensions, etc. Rename to `getSemanticMembers()` to indicate that
these are all of the members that are semantically part of that
context.
Clean up the implementation slightly so it only forces type checking
for the conformances within that particular context (using
`getLocalConformances()`) and doesn't need to list out each of the
protocols it cares about.
Make sure we consistently use getParentForLookup() and not getParent()
when looking at generic DeclContexts. This is because an extension or
protocol that is nested inside of another generic context must never
inherit generic parameters from the parent context.
We already had this invariant enforced in some places, but now that we
do it more consistently we can fix more crashes of this kind.
Fixes <rdar://problem/58813746>, <https://bugs.swift.org/browse/SR-13004>.
We had some duplicated logic between getResilienceExpansion() and
getFragileFunctionKind(). Clean this up by moving the latter into
AST, and re-implementing the former in terms of the latter.
This also fixes a crash in at least one case where these two
implementations had previously diverged.
Fixes <rdar://problem/60605117>.
`SynthesizedFileUnit` is a container for synthesized declarations. Currently, it
only supports module-level declarations.
It is used by the SIL differentiation transform, which generates implicit struct
and enum declarations.
Type erasure requires a circular construction by its very nature:
@_typeEraser(AnyProto)
protocol Proto { /**/ }
public struct AnyProto : Proto {}
If we eagerly resolve AnyProto, the chain of resolution steps that
deserialization must make goes a little something like this:
Lookup(Proto)
-> Deserialize(@_typeEraser(AnyProto))
-> Lookup(AnyProto)
-> DeserializeInheritedStuff(AnyProto)
-> Lookup(Proto)
This cycle could be broken if the order of incremental inputs was
such that we had already cached the lookup of Proto.
Resolve this cycle in any case by suspending the deserialization of the
type eraser until the point it's demanded by adding
ResolveTypeEraserTypeRequest.
rdar://61270195
A request is intended to be a pure function of its inputs. That function could, in theory, fail. In practice, there were basically no requests taking advantage of this ability - the few that were using it to explicitly detect cycles can just return reasonable defaults instead of forwarding the error on up the stack.
This is because cycles are checked by *the Evaluator*, and are unwound by the Evaluator.
Therefore, restore the idea that the evaluate functions are themselves pure, but keep the idea that *evaluation* of those requests may fail. This model enables the best of both worlds: we not only keep the evaluator flexible enough to handle future use cases like cancellation and diagnostic invalidation, but also request-based dependencies using the values computed at the evaluation points. These aforementioned use cases would use the llvm::Expected interface and the regular evaluation-point interface respectively.
When a “separately imported overlay” is added to a SourceFile, two things happen:
1. The direct import of the underlying module is removed from getImports*() by default. It is only visible if the caller passes ImportFilterKind:: ShadowedBySeparateOverlay. This means that non-module-scoped lookups will search _OverlayModule before searching its re-export UnderlyingModule, allowing it to shadow underlying declarations.
2. When you ask for lookupInModule() to look in the underlying module in that source file, it looks in the overlays instead. This means that UnderlyingModule.foo() can find declarations in _OverlayModule.
Effectively revert #28907. The request evaluator will also catch re-entrancy here, and those cycles can be broken with NameLookupFlags::IgnoreNewExtensions.
