Allow passing additional compiler/linker flags for the tests

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

Reviewers: EricWF

Reviewed By: EricWF

Subscribers: christof, mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D42139

llvm-svn: 325914

libcxx/test/CMakeLists.txt

@@ -9,6 +9,11 @@ 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)

libcxx/test/lit.site.cfg.in

@@ -22,6 +22,9 @@ 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@"

libcxx/utils/libcxx/test/config.py

@@ -510,6 +510,9 @@ class Configuration(object):
             # 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
@@ -794,6 +797,9 @@ class Configuration(object):
                                         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.