`clangSema.isCompleteType` checks for decl visibility according to the module visibility rules, which we don't actually need. What we need to check is whether the record has a definition – this is the check we already use elsewhere in ClangImporter.
This makes sure that we can import `std::function` on Windows.
rdar://103979602
Clang rejects code that tries to call a constructor of an abstract C++ class with an error: "Variable type 'Base' is an abstract class". Swift should reject this as well.
rdar://119689243
libc++ recently split the `std` module into many top-level modules: 571178a21a
Previously if a C++ module had `#include <iosfwd>`, importing that module in Swift would make the entire C++ stdlib visible from Swift, since it was a single top-level Clang module. After libc++ got split it doesn't automatically do so, but we need to preserve the current behavior for Swift users.
rdar://119270491
libc++ recently split the `std` module into many top-level modules: 571178a21a
This prevented the conformances to `CxxSet`, `CxxVector`, etc. from being synthesized with a fresh libc++ version.
rdar://119270491
Swift names provided via C attributes or API notes can be parsed as
special names, such as `init` or `subscript`. However, doing so would
cause the Clang importer to crash, because it assumes that these names
are always identifiers. In these places, we actually want to treat
them as identifiers, where special names are mapped back to their
keywords. Introduce a function to do that, and use it consistently.
If a C++ function cannot be imported into Swift, we try to emit a diagnostic that explains why. This diagnostic wasn't always correct: for functions that return a C++ struct, we emitted a note saying "function uses foreign reference type in a return type which breaks 'swift_shared_reference' contract" even if the return type is a trivial struct without any attributes. This was emitted unless there was another diagnostic that we also provided for the same function.
Previously, `friend` operators declared in C++ classes were added to the lookup table when the class is being imported.
The operators were added to the wrong lookup table if the class is declared in a C++ namespace. Since a namespace can span across multiple Clang modules, its contents should be added to a translation unit level lookup table, not to a module level lookup table.
This change makes sure we add `friend` operators to the lookup table earlier, when we are actually building the lookup table. Note that this is not possible for class template instantiations, because those are instantiated later, so for templates we still handle `friend` operators when importing the instantiation.
rdar://116349899
The spelling kind was only ever set to
`StaticSpellingKind::None`, and the static location
was never used for anything (and should be queried
on the storage anyway). This doesn't affect the
computation of `isStatic` since `IsStaticRequest`
already takes the static-ness from the storage for
accessors.
If `struct Base` is a public base class of `struct Derived`, and `Base` is annotated with `__attribute__((swift_attr("conforms_to:MyModule.MyProto")))`, `Derived` will now also get a conformance to `MyProto`.
rdar://113971944
This is a simple work around to avoid importing virtual functions when symbolic
imports are turned on. Test cases that were failing before this WA are in
test/Interop/Cxx/symbolic-imports.
Thanks to Alex Lorenz for providing this WA to me (@hyp).
This is a forward-interop feature that wires up existing functionality for
synthesizing base class function calling to enable virtual function calling.
The general idea is to sythesize the pattern:
```
// C++ class:
struct S { virtual auto f() -> int { return 42; } };
// Swift User:
var s = S()
print("42: \(s.f())")
// Synthetized Swift Code:
extension S { func f() -> CInt { __synthesizedVirtualCall_f() } }
// Synthetized C/C++ Code:
auto __cxxVirtualCall_f(S *s) -> int { return s->f(); }
```
The idea here is to allow for the synthetized C++ bits from the Clang side to
handle the complexity of virtual function calling.
If a C++ type `Derived` inherits from `Base` privately, the public methods from `Base` should not be callable on an instance of `Derived`. However, C++ supports exposing such methods via a using declaration: `using MyPrivateBase::myPublicMethod;`.
MSVC started using this feature for `std::optional` which means Swift doesn't correctly import `var pointee: Pointee` for instantiations of `std::optional` on Windows. This prevents the automatic conformance to `CxxOptional` from being synthesized.
rdar://114282353 / resolves https://github.com/apple/swift/issues/68068
For any operation that can throw an error, such as calls, property
accesses, and non-exhaustive do..catch statements, record the thrown
error type along with the conversion from that thrown error to the
error type expected in context, as appropriate. This will prevent
later stages from having to re-compute the conversion sequences.
When importing a C++ struct, if its owning module requires cplusplus, Swift tried to auto-conform it to certain protocols from the Cxx module. This triggers name lookup in the clang struct, specifically for `__beginUnsafe()` and `__endUnsafe` methods, which imports all of the base structs including their methods.
This moves the import of base structs out of the name lookup request, preventing cycles.
rdar://116426238
When importing a C++ class template instantiation, Swift translates the template parameter type names from C++ into their Swift equivalent.
For instance, `basic_string<wchar_t, char_traits<wchar_t>, allocator<wchar_t>>` gets imported as `basic_string<Scalar, char_traits<Scalar>, allocator<Scalar>>`: `wchar_t` is imported as `CWideChar`, which is a typealias for `Scalar` on most platforms including Darwin. Notice that Swift goes through the `CWideChar` typealias on the specific platform. Another instantiation `basic_string<uint32_t, char_traits<uint32_t>, allocator<uint32_t>>` also gets imported as `basic_string<Scalar, char_traits<Scalar>, allocator<Scalar>>`: `uint32_t` is also imported as `Scalar`. This is problematic because we have two distinct C++ types that have the same name in Swift.
This change makes sure Swift doesn't go through typealiases when emitting names of template parameters, so `wchar_t` would now get printed as `CWideChar`, `int` would get printed as `CInt`, etc.
This also encourages clients to use the correct type (`CInt`, `CWideChar`, etc) instead of relying on platform-specific typealiases.
rdar://115673622
