An async @objc method only checks if its completion handler parameter is null if ClangImporter forces it to. This is fine for @objc with a generated header, because the generated header always declares the parameter _Nonnull, but clients ignore that annotation and pass nil anyway often enough that for @objc @implementation, we ought to be defensive.
We can achieve this by simply making the completion handler’s type Optional—SILGen already looks for this and knows what to do when it sees it.
Fixes rdar://130527373.
When an @objc @implementation class requires the use of `ClassMetadataStrategy::Update` because some of its stored properties do not have fixed sizes, we adjust the direct field offsets during class realization by emitting a custom metadata update function which calls a new entry point in the Swift runtime. That entry point adjusts field offsets like `swift_updateClassMetadata2()`, but it only assumes that the class has Objective-C metadata, not Swift metadata.
This commit introduces an alternative mechanism which does the same thing without using any Swift-only metadata. It’s a rough implementation with important limitations:
• We’re currently using the field offset vector, which means that field offsets are being emitted into @objc @implementation classes; these will be removed.
• The new Swift runtime entry point duplicates a lot of `swift_updateClassMetadata2()`’s implementation; it will be refactored into something much smaller and more compact.
• Availability bounds for this feature have not yet been implemented.
Future commits in this PR will correct these issues.
When @_objcImplementation is used to implement a C function marked with __asm__, take the attribute into account when mangling SIL references.
In theory this change should also make `clang::OverloadableAttr` functions mangle correctly, but in practice the matching logic for @_cdecl @_objcImplementation doesn’t currently support overloadable functions (and it’s not wise to try anyway, since clang doesn’t promise that their ABI won’t change).
Fixes rdar://120503717.
A class that uses @objcImplementation but does not explicitly declare any designated initializers previously did not override the superclass initializers, so its stored properties would not be initialized. Opt these classes into that logic and adjust it to add the initializers to the @objcImplementation extension instead of the ClassDecl itself.
Fixes rdar://105008242.
This commit begins to generate correct metadata for @_objcImplementation extensions:
• Swift-specific metadata and symbols are not generated.
• For main-class @_objcImpls, we visit the class to emit metadata, but visit the extension’s members.
• Includes both IR tests and executable tests, including coverage of same-module @objc subclasses, different-module @objc subclasses, and clang subclasses.
The test cases do not yet cover stored properties.
