[libcxx-commits] [libcxx] [libc++] Run the Lit test suite against an installed version of the library (PR #96910)

[Martin Storsjö via libcxx-commits]

mstorsjo wrote:

> It is failing because we try installing the `install-unwind-test-suite-prefix` target which depends on `unwind-headers` and `unwind`, however that whole code block is gated on `LIBCXXABI_USE_LLVM_UNWINDER`. On Windows though, it looks like you're not building libunwind at all

Side note, we _do_ build libunwind on Windows. We don't build it in clang-cl configs, but we do build it in mingw configs.

> so I don't understand why that code path is taken. Do you understand what's going on?

In https://github.com/llvm/llvm-project/blob/main/libcxx/CMakeLists.txt#L279 you have `option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." ON)` - which defaults this variable to `ON`, regardless of whether either `libcxxabi` or `libunwind` even are enabled. In this PR, you're checking `if (LIBCXXABI_USE_LLVM_UNWINDER)` and reference libunwind within that.

https://github.com/llvm/llvm-project/pull/96910