C++ code can return values that depend on the storage that backs the
references that were passed in as argument. Thus, swift should not
introdue temporary copies of that storage before invoking those
functions as they could result in lifetime issues.
In GenCall, fix the IR gen for C++ method calls as under MSVC as the
calling conventions for free functions and C++ methods can be
different. This also fixes the missing inreg (on sret arguments)
issues on Windows ARM64. Also refactor to use CGFunctionInfo
returnInfo isSretAfterThis to detect when to reorder the sret and the
this arguments under MSVC.
In ClagImporter, don't drop the return type for the compound
assignment operators such as operator+= when the return value is a
reference so that the CGFunctionInfo will be correctly indicate an
indirect return for the compound assignment operators.
When we have both const and non-const version of a function, we import
the non-cont version with the "Mutating" suffix. This logic, however, is
redundant for static member functions as those can never be marked as
"const" since they don't have a "self" or "this" to mutate.
rdar://120858502
Fixes https://github.com/apple/swift/issues/66326
This allows us to reneable Windows method tests. Note that Windows still has
a broken convention for non-trivial record with non-trivial destructor but
trivial copy-constructor, so classes in the methods.swift test need an explicit
copy constructor.
Fixes rdar://88391102
When importing a C++ struct that contains two methods that only differ in const-ness, we append `Mutating` to the name of the non-const method to make it possible to call from Swift unambiguously.
Unfortunately that logic was dependent on the order in which we import methods of a class: the `Mutating` suffix was added when another method with the same name was already imported.
This caused lookup failures, and the behavior was incorrect when the pair of methods return instances of an unsafe type: the const overload was renamed as `Unsafe` properly, but the non-const overload was not renamed.
