[libcxx] Allow tests to link with static libc++abi/libc++ even if the shared version is present

Summary:
This is essentially D71894, but for libc++.

This is needed for running libc++ tests over SSH.

Reviewers: EricWF, ldionne, phosek, mehdi_amini, mclow.lists, jroelofs, bcraig, #libc

Reviewed By: ldionne, phosek, #libc

Subscribers: mgorny, christof, dexonsmith, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D72687

Author: broadwaylamb

libcxx/test/CMakeLists.txt

@@ -26,10 +26,40 @@ if (LIBCXX_ENABLE_ABI_LINKER_SCRIPT)
   set(LIBCXXABI_USE_LLVM_UNWINDER OFF)
 endif()
 
+option(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI
+       "Whether the libc++ tests should link with the shared libc++abi library"
+       ${LIBCXXABI_ENABLE_SHARED})
+
+option(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX
+       "Whether the libc++ tests should link with the shared libc++ library"
+       ${LIBCXX_ENABLE_SHARED})
+
+if(DEFINED LIBCXXABI_ENABLE_SHARED
+   AND LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI
+   AND NOT LIBCXXABI_ENABLE_SHARED)
+  message(FATAL_ERROR "LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI being ON requires LIBCXXABI_ENABLE_SHARED to be ON")
+endif()
+
+if(DEFINED LIBCXXABI_ENABLE_STATIC
+   AND NOT LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI
+   AND NOT LIBCXXABI_ENABLE_STATIC)
+  message(FATAL_ERROR "LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI being OFF requires LIBCXXABI_ENABLE_STATIC to be ON")
+endif()
+
+if(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX AND NOT LIBCXX_ENABLE_SHARED)
+  message(FATAL_ERROR "LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX being ON requires LIBCXX_ENABLE_SHARED to be ON")
+endif()
+
+if(NOT LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX AND NOT LIBCXX_ENABLE_STATIC)
+  message(FATAL_ERROR "LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX being OFF requires LIBCXX_ENABLE_STATIC to be ON")
+endif()
+
 pythonize_bool(LIBCXX_ENABLE_EXCEPTIONS)
 pythonize_bool(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY)
 pythonize_bool(LIBCXX_ENABLE_RTTI)
 pythonize_bool(LIBCXX_ENABLE_SHARED)
+pythonize_bool(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX)
+pythonize_bool(LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI)
 pythonize_bool(LIBCXX_ENABLE_FILESYSTEM)
 pythonize_bool(LIBCXX_BUILD_32_BITS)
 pythonize_bool(LIBCXX_GENERATE_COVERAGE)

libcxx/test/lit.site.cfg.in

@@ -8,7 +8,7 @@ config.enable_exceptions        = @LIBCXX_ENABLE_EXCEPTIONS@
 config.enable_experimental      = @LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY@
 config.enable_filesystem        = @LIBCXX_ENABLE_FILESYSTEM@
 config.enable_rtti              = @LIBCXX_ENABLE_RTTI@
-config.enable_shared            = @LIBCXX_ENABLE_SHARED@
+config.enable_shared            = @LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXX@
 config.enable_32bit             = @LIBCXX_BUILD_32_BITS@
 config.cxx_abi                  = "@LIBCXX_CXX_ABI_LIBNAME@"
 config.use_sanitizer            = "@LLVM_USE_SANITIZER@"
@@ -31,7 +31,7 @@ config.builtins_library         = "@LIBCXX_BUILTINS_LIBRARY@"
 config.has_libatomic            = @LIBCXX_HAS_ATOMIC_LIB@
 config.use_libatomic            = @LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB@
 config.debug_build              = @LIBCXX_DEBUG_BUILD@
-config.libcxxabi_shared         = @LIBCXXABI_ENABLE_SHARED@
+config.libcxxabi_shared         = @LIBCXX_LINK_TESTS_WITH_SHARED_LIBCXXABI@
 config.cxx_ext_threads          = @LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY@
 config.pstl_src_root            = "@ParallelSTL_SOURCE_DIR@" if @LIBCXX_ENABLE_PARALLEL_ALGORITHMS@ else None
 config.pstl_obj_root            = "@ParallelSTL_BINARY_DIR@" if @LIBCXX_ENABLE_PARALLEL_ALGORITHMS@ else None