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

Summary:
Right now the only way to force libc++abi tests to link with the static version of libc++abi is to set `LIBCXXABI_ENABLE_SHARED` to `OFF`. However, this doesn't work when libc++abi is built as standalone project because of [this](https://github.com/llvm/llvm-project/blob/54c522420347e58aa7bae1892cf5c5672b57c875/libcxxabi/CMakeLists.txt#L503-L519).

This change allows specifying the version of the library for tests to link with.

This is useful for remote testing, for example, with `SSHExecutor`, where we _have_ to link with libc++abi statically.

Two new CMake options are introduced here: `LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI` and `LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX`. They can be set to `OFF` to tell the test utility to link tests with the static libraries.

It shouldn't break anything, because the default values of these options are set such that the test utility will behave the same way.

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

Subscribers: mgorny, christof, ldionne, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D71894

3 files changed, 33 insertions, 3 deletions

diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 0ddcd5f..f3698e9 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -92,6 +92,14 @@ usual symlinks pointing to that.")
 option(LIBCXXABI_ENABLE_SHARED "Build libc++abi as a shared library." ON)
 option(LIBCXXABI_ENABLE_STATIC "Build libc++abi as a static library." ON)
 
+option(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI
+       "Whether the libc++abi tests should link with the shared libc++abi library"
+       ${LIBCXXABI_ENABLE_SHARED})
+
+option(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX
+       "Whether the libc++abi tests should link with the shared libc++ library"
+       ${LIBCXX_ENABLE_SHARED})
+
 cmake_dependent_option(LIBCXXABI_INSTALL_STATIC_LIBRARY
   "Install the static libc++abi library." ON
   "LIBCXXABI_ENABLE_STATIC;LIBCXXABI_INSTALL_LIBRARY" OFF)
@@ -115,6 +123,26 @@ if (NOT LIBCXXABI_ENABLE_SHARED AND NOT LIBCXXABI_ENABLE_STATIC)
   message(FATAL_ERROR "libc++abi must be built as either a shared or static library.")
 endif()
 
+if(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI AND NOT LIBCXXABI_ENABLE_SHARED)
+  message(FATAL_ERROR "LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI being ON requires LIBCXXABI_ENABLE_SHARED to be ON")
+endif()
+
+if(NOT LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI AND NOT LIBCXXABI_ENABLE_STATIC)
+  message(FATAL_ERROR "LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI being OFF requires LIBCXXABI_ENABLE_STATIC to be ON")
+endif()
+
+if(DEFINED LIBCXX_ENABLE_SHARED 
+   AND LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX
+   AND NOT LIBCXX_ENABLE_SHARED)
+  message(FATAL_ERROR "LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX being ON requires LIBCXX_ENABLE_SHARED to be ON")
+endif()
+
+if(DEFINED LIBCXX_ENABLE_STATIC
+   AND NOT LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX 
+   AND NOT LIBCXX_ENABLE_STATIC)
+  message(FATAL_ERROR "LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX being OFF requires LIBCXX_ENABLE_STATIC to be ON")
+endif()
+
 if (LLVM_EXTERNAL_LIBCXX_SOURCE_DIR)
   set(LIBCXXABI_LIBCXX_SRC_DIRS ${LLVM_EXTERNAL_LIBCXX_SOURCE_DIR})
 else()
@@ -209,7 +237,7 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 # directory.
 if (NOT LIBCXXABI_LIBCXX_LIBRARY_PATH)
   set(LIBCXXABI_LIBCXX_LIBRARY_PATH "${LIBCXXABI_LIBRARY_DIR}" CACHE PATH
-      "The path to libc++ library.")
+      "The path to libc++ library." FORCE)
 endif()
 
 # Check that we can build with 32 bits if requested.
diff --git a/libcxxabi/test/CMakeLists.txt b/libcxxabi/test/CMakeLists.txt
index 60e052d..23c0dac 100644
--- a/libcxxabi/test/CMakeLists.txt
+++ b/libcxxabi/test/CMakeLists.txt
@@ -20,6 +20,8 @@ pythonize_bool(LIBCXXABI_USE_LLVM_UNWINDER)
 pythonize_bool(LIBCXXABI_USE_COMPILER_RT)
 pythonize_bool(LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY)
 pythonize_bool(LIBCXX_ENABLE_PARALLEL_ALGORITHMS)
+pythonize_bool(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX)
+pythonize_bool(LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI)
 set(LIBCXXABI_TARGET_INFO "libcxx.test.target_info.LocalTI" CACHE STRING
     "TargetInfo to use when setting up test environment.")
 set(LIBCXXABI_EXECUTOR "None" CACHE STRING
diff --git a/libcxxabi/test/lit.site.cfg.in b/libcxxabi/test/lit.site.cfg.in
index 8ac2fa4..8125e89 100644
--- a/libcxxabi/test/lit.site.cfg.in
+++ b/libcxxabi/test/lit.site.cfg.in
@@ -16,8 +16,8 @@ config.sanitizer_library        = "@LIBCXXABI_SANITIZER_LIBRARY@"
 config.enable_32bit             = @LIBCXXABI_BUILD_32_BITS@
 config.target_info              = "@LIBCXXABI_TARGET_INFO@"
 config.executor                 = "@LIBCXXABI_EXECUTOR@"
-config.libcxxabi_shared         = @LIBCXXABI_ENABLE_SHARED@
-config.enable_shared            = @LIBCXX_ENABLE_SHARED@
+config.libcxxabi_shared         = @LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXXABI@
+config.enable_shared            = @LIBCXXABI_LINK_TESTS_WITH_SHARED_LIBCXX@
 config.enable_exceptions        = @LIBCXXABI_ENABLE_EXCEPTIONS@
 config.host_triple              = "@LLVM_HOST_TRIPLE@"
 config.target_triple            = "@TARGET_TRIPLE@"