Allow passing additional compiler/linker flags for the tests

[arichardson]

Summary

These flags can be specified using the CMake variables
LIBCXX_TEST_LINKER_FLAGS and LIBCXX_TEST_COMPILER_FLAGS.
When building the tests for CHERI I need to pass additional
flags (such as -mabi=n64 or -mabi=purecap) to the compiler
for our test configurations

[arichardson]

ping

[EricWF]

I'm fine with this, but I don't really think it's a good solution (but none of our LIT config is ideal). In particular for the link flags might not work well, because the order of linker flags matters a lot and this doesn't really deal with that. But if it works for your case.

libcxx/trunk/test/CMakeLists.txt

 macro(pythonize_bool var)
   if (${var})
     set(${var} True)
   else()
     set(${var} False)
   endif()
 endmacro()
 
 set(LIBCXX_LIT_VARIANT "libcxx" CACHE STRING
     "Configuration variant to use for LIT.")
 
+set(LIBCXX_TEST_LINKER_FLAGS "" CACHE STRING
+    "Additonal linker flags to pass when compiling the tests")
+set(LIBCXX_TEST_COMPILER_FLAGS "" CACHE STRING
+    "Additonal linker flags to pass when compiling the tests")
+
 # The tests shouldn't link to any ABI library when it has been linked into
 # libc++ statically or via a linker script.
 if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY OR LIBCXX_ENABLE_ABI_LINKER_SCRIPT)
   set(LIBCXX_CXX_ABI_LIBNAME "none")
 endif()
 
 # The tests shouldn't link to libunwind if we have a linker script which
 # already does so.

libcxx/trunk/test/lit.site.cfg.in

 config.configuration_variant    = "@LIBCXX_LIT_VARIANT@"
 config.host_triple              = "@LLVM_HOST_TRIPLE@"
 config.target_triple            = "@TARGET_TRIPLE@"
 config.use_target               = len("@LIBCXX_TARGET_TRIPLE@") > 0
 config.sysroot                  = "@LIBCXX_SYSROOT@"
 config.gcc_toolchain            = "@LIBCXX_GCC_TOOLCHAIN@"
 config.generate_coverage        = "@LIBCXX_GENERATE_COVERAGE@"
 config.target_info              = "@LIBCXX_TARGET_INFO@"
+config.test_linker_flags        = "@LIBCXX_TEST_LINKER_FLAGS@"
+config.test_compiler_flags      = "@LIBCXX_TEST_COMPILER_FLAGS@"
+
 config.executor                 = "@LIBCXX_EXECUTOR@"
 config.llvm_unwinder            = "@LIBCXXABI_USE_LLVM_UNWINDER@"
 config.compiler_rt              = "@LIBCXX_USE_COMPILER_RT@"
 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.cxx_ext_threads          = "@LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY@"
 
 # Let the main config do the real work.
 config.loaded_site_config = True
 lit_config.load_config(config, "@LIBCXX_SOURCE_DIR@/test/lit.cfg")

libcxx/trunk/utils/libcxx/test/config.py

def configure_compile_flags(self):
         self.cxx.compile_flags += shlex.split(compile_flags_str)
         if self.is_windows:
             # FIXME: Can we remove this?
             self.cxx.compile_flags += ['-D_CRT_SECURE_NO_WARNINGS']
             # Required so that tests using min/max don't fail on Windows,
             # and so that those tests don't have to be changed to tolerate
             # this insanity.
             self.cxx.compile_flags += ['-DNOMINMAX']
+        additional_flags = self.get_lit_conf('test_compiler_flags')
+        if additional_flags:
+            self.cxx.compile_flags += shlex.split(additional_flags)
 
     def configure_default_compile_flags(self):
         # Try and get the std version from the command line. Fall back to
         # default given in lit.site.cfg is not present. If default is not
         # present then force c++11.
         std = self.get_lit_conf('std')
         if not std:
             # Choose the newest possible language dialect if none is given.
def configure_link_flags_cxx_library_path(self):
                     self.add_path(self.exec_env, self.cxx_runtime_root)
         elif os.path.isdir(str(self.use_system_cxx_lib)):
             self.cxx.link_flags += ['-L' + self.use_system_cxx_lib]
             if not self.is_windows:
                 self.cxx.link_flags += ['-Wl,-rpath,' +
                                         self.use_system_cxx_lib]
             if self.is_windows and self.link_shared:
                 self.add_path(self.cxx.compile_env, self.use_system_cxx_lib)
+        additional_flags = self.get_lit_conf('test_linker_flags')
+        if additional_flags:
+            self.cxx.link_flags += shlex.split(additional_flags)
 
     def configure_link_flags_abi_library_path(self):
         # Configure ABI library paths.
         self.abi_library_root = self.get_lit_conf('abi_library_path')
         if self.abi_library_root:
             self.cxx.link_flags += ['-L' + self.abi_library_root]
             if not self.is_windows:
                 self.cxx.link_flags += ['-Wl,-rpath,' + self.abi_library_root]