[6.2][cxx-interop] Fix duplicate symbol error with default arguments #84165
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Explanation: We synthesize a Swift function that only calls a C++ funtion that produces the default argument. We produce this function for each module that imports the C++ function with the default argument. This symbol needs to be public as it is created in the context of the Clang module and used from the Swift module. To avoid the linker errors, we always emit this function into the client which is also the right thing to do as the whole body is a single function call.
Issues: rdar://160182651
Original PRs: #82333
Risk: Low, this is merged to main in early July and no one complained yet. And the change is straightforward.
Testing: Added a compiler test.
Reviewers: @egorzhdan