[libcxx] Add support for sanitizers on OS X.

[EricWF]

Summary

This patch adds special configuration logic to find the compiler_rt libraries required by sanitizers on OS X. The supported sanitizers are Address and Undefined.

[mclow.lists]

This looks fine to me; and seems to work on my system.

lib/CMakeLists.txt

 endif()
 target_link_libraries(cxx ${libraries})
 
+if (APPLE AND LLVM_USE_SANITIZER)
+  if ("${LLVM_USE_SANITIZER}" STREQUAL "Address")
+    set(LIBFILE "libclang_rt.asan_osx_dynamic.dylib")
+  elseif("${LLVM_USE_SANITIZER}" STREQUAL "Undefined")
+    set(LIBFILE "libclang_rt.ubsan_osx_dynamic.dylib")
+  else()
+    message(WARNING "LLVM_USE_SANITIZER=${LLVM_USE_SANITIZER} is not supported on OS X")
+  endif()
+  if (LIBFILE)
+    execute_process(COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=lib OUTPUT_VARIABLE LIBDIR RESULT_VARIABLE Result)
+    if (NOT ${Result} EQUAL "0")
+      message(FATAL "Failed to find library resource directory")
+    endif()
+    string(STRIP "${LIBDIR}" LIBDIR)
+    set(LIBDIR "${LIBDIR}/darwin/")
+    if (NOT IS_DIRECTORY "${LIBDIR}")
+      message(FATAL_ERROR "Cannot find compiler-rt directory on OS X required for LLVM_USE_SANITIZER")
+    endif()
+    set(LIBCXX_SANITIZER_LIBRARY "${LIBDIR}/${LIBFILE}")
+    set(LIBCXX_SANITIZER_LIBRARY "${LIBCXX_SANITIZER_LIBRARY}" PARENT_SCOPE)
+    message(STATUS "Manually linking compiler-rt library: ${LIBCXX_SANITIZER_LIBRARY}")
+    target_link_libraries(cxx "${LIBCXX_SANITIZER_LIBRARY}")
+    target_link_libraries(cxx "-Wl,-rpath,${LIBDIR}")
+  endif()
+endif()
+
 
 # Setup flags.
 append_if(LIBCXX_COMPILE_FLAGS LIBCXX_HAS_FPIC_FLAG -fPIC)

test/libcxx/test/config.py

                                    '-fno-sanitize-recover']
                 self.cxx.compile_flags += ['-O3']
                 self.config.available_features.add('ubsan')
+                if self.target_info.platform() == 'darwin':
+                    self.config.available_features.add('sanitizer-new-delete')
             elif san == 'Thread':
                 self.cxx.flags += ['-fsanitize=thread']
                 self.config.available_features.add('tsan')

             else:
                 self.lit_config.fatal('unsupported value for '
                                       'use_sanitizer: {0}'.format(san))
+            san_lib = self.get_lit_conf('sanitizer_library')
+            if san_lib:
+                self.cxx.link_flags += [
+                    san_lib, '-Wl,-rpath,%s' % os.path.dirname(san_lib)]
 
     def configure_coverage(self):
         self.generate_coverage = self.get_lit_bool('generate_coverage', False)

test/lit.site.cfg.in

 config.enable_monotonic_clock   = "@LIBCXX_ENABLE_MONOTONIC_CLOCK@"
 config.cxx_abi                  = "@LIBCXX_CXX_ABI_LIBNAME@"
 config.use_sanitizer            = "@LLVM_USE_SANITIZER@"
+config.sanitizer_library        = "@LIBCXX_SANITIZER_LIBRARY@"
 config.abi_library_path         = "@LIBCXX_CXX_ABI_LIBRARY_PATH@"
 config.configuration_variant    = "@LIBCXX_LIT_VARIANT@"
 config.target_triple            = "@LIBCXX_TARGET_TRIPLE@"