In the reverse interop header we generated move constructors that call
abort at runtime. This is problematic for several reasons:
* In C++14 and below some of our own generated functions like _make
ended up calling the move constructor. Those are calling abort and
also trigger unreachable code warning in newer versions of Clang.
In C++17 and up it is fine due to the guaranteed copy elision.
* Type traits are fooled and think these types are movable. As a result,
libraries could generate calls to the aborting move ctor.
This PR removes the generation of move operations. As we generate copy
operations, the compiler will not declare or define the move operations
implicitly. Whenever the user goes out of their way and try to move an
object they will get a copy instead.
rdar://150793518
PrintAsClang is supposed to emit declarations in the same order regardless of the compiler’s internal state, but we have repeatedly found that our current criteria are inadequate, resulting in non-functionality-affecting changes to generated header content. Add a diagnostic that’s emitted when this happens soliciting a bug report.
Since there *should* be no cases where the compiler fails to order declarations, this diagnostic is never actually emitted. Instead, we test this change by enabling `-verify` on nearly all PrintAsClang tests to make sure they are unaffected.
This did demonstrate a missing criterion that only mattered in C++ mode: extensions that varied only in their generic signature were not sorted stably. Add a sort criterion for this.
It is really involved to change how methods and classes are emitted into
the header so this patch introduces the impression of nested structs
through using statements and still emits the structs themselves as top
level structs. It emits them in their own namespace to avoid name
collisions. This patch also had to change some names to be fully
qualified to avoid some name lookup errors in case of nested structs.
Moreover, nesting level of 3 and above requires C++17 because it relies
on nested namespaces. Only nested structs are supported, not nested
classes.
Since this patch is already started to grow quite big, I decided to put
it out for reviews and plan to address some of the shortcomings in a
follow-up PR.
rdar://118793469
The generated header would not compile without these dependencies. Moreover
users probably expect all-public option to be the most permissive filter
including the maximal amount of declarations.
Swift-to-C++ thunk printing for functions didn’t really take into account Swift’s `Never` type. This type maps to `SWIFT_NORETURN`, but it also requires other tweaks to code generation, such as omitting the `return` keyword. (Removing that requires minor changes to many tests.)
Fixes rdar://124137073.
This macro applies always_inline in addition to inline. It also applies artificial, which lets debugger know that this is an artificial function. The used attribute is added in debug builds to ensure that the symbol is emitted in the binary so that LLDB can invoke it.
Each emitted declaration is annotated with the external_source_symbol with its own USR, to allow Clang's indexer to recognize this declaration as a Swift declaration with a specific USR
