ldionne
commented
2 months ago We are in the process of significantly rewriting our modulemap in libc++: https://github.com/llvm/llvm-project/pull/107638
This will yield significant compilation time speedups when using modules. IMO what we should do here (as far as trunk libc++ is concerned) is to keep moving towards that change and make sure that it doesn't break interop (in fact ideally it would fix the issues you're seeing). If we need to backport a partial fix to an already-released version of libc++, that's another story and I would tackle that separately.
Do you see problems when using libc++ as it shipped with LLVM 19? Perhaps the NDK doesn't ship such a recent version yet?
finagolfin
michael-yuji
Description
I just tried building the Swift 6.1 trunk Sep.4 source snapshot natively on Android 13 AArch64 with the new Android NDK 27 sysroot and it failed with this linker error:
Modifying the libc++ module map like this got it to build again:
This worked fine when building the Aug. 6 trunk source snapshot with the NDK 26b sysroot last month, so I looked into it and that NDK did not ship with @ian-twilightcoder's reorganization of the libc++ module map from last summer, llvm/llvm-project@571178a21. NDK 27 ships with a lightly-patched version of that upstream libc++ module map, but I don't see anything when comparing their changes to the version in swiftlang/llvm-project that would cause this error.
I also see 11 newly failing C++ Interop tests from the Swift compiler validation suite, which all worked fine last month with NDK 26b:
Since the upstream libc++ reorg shipped with the LLVM 17 release last fall and there don't appear to be any fixes merged for this issue since, I assume this doesn't affect clang/C++, only Swift->C++ Interop, so I filed the issue here.
Reproduction
See commands pasted above
Expected behavior
No linker errors
Environment
Android 13 AArch64 in the Termux app
Additional information
I'll see what other module map changes get those 11 failing C++ Interop tests to build again. In the meantime, aren't there other environments using Swift with libc++ also that fail in this way?
@egorzhdan or @ldionne, in addition to Ian, let me know what you think.