Index: cmake/Modules/AddCompilerRT.cmake
===================================================================
--- cmake/Modules/AddCompilerRT.cmake
+++ cmake/Modules/AddCompilerRT.cmake
@@ -280,6 +280,10 @@
   if(NOT COMPILER_RT_STANDALONE_BUILD)
     list(APPEND LIBCXX_DEPS clang)
   endif()
+  set(LIBCXX_SHARED_LINKER_FLAGS)
+  if (APPLE)
+    set(LIBCXX_SHARED_LINKER_FLAGS "-undefined dynamic_lookup")
+  endif()
 
   ExternalProject_Add(${name}
     PREFIX ${prefix}
@@ -289,6 +293,7 @@
                -DCMAKE_C_FLAGS=${LIBCXX_CFLAGS}
                -DCMAKE_CXX_FLAGS=${LIBCXX_CFLAGS}
                -DCMAKE_BUILD_TYPE=Release
+               -DCMAKE_SHARED_LINKER_FLAGS=${LIBCXX_SHARED_LINKER_FLAGS}
                -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
     LOG_BUILD 1
     LOG_CONFIGURE 1
Index: test/tsan/CMakeLists.txt
===================================================================
--- test/tsan/CMakeLists.txt
+++ test/tsan/CMakeLists.txt
@@ -6,8 +6,7 @@
   list(APPEND TSAN_TEST_DEPS tsan)
 endif()
 if(COMPILER_RT_HAS_LIBCXX_SOURCES AND
-   COMPILER_RT_TEST_COMPILER_ID STREQUAL "Clang"
-   AND NOT APPLE)
+   COMPILER_RT_TEST_COMPILER_ID STREQUAL "Clang")
   list(APPEND TSAN_TEST_DEPS libcxx_tsan)
   set(TSAN_HAS_LIBCXX True)
 else()
Index: test/tsan/lit.cfg
===================================================================
--- test/tsan/lit.cfg
+++ test/tsan/lit.cfg
@@ -37,6 +37,9 @@
 clang_tsan_cflags = ["-fsanitize=thread",
                      "-Wall",
                      "-m64"] + config.debug_info_flags + extra_cflags
+if config.host_os == 'Darwin':
+  clang_tsan_cflags.extend(["-isystem", os.path.join(config.test_source_root)])
+
 clang_tsan_cxxflags = config.cxx_mode_flags + clang_tsan_cflags
 # Add additional flags if we're using instrumented libc++.
 # Instrumented libcxx currently not supported on Darwin.
@@ -46,11 +49,16 @@
                              "tsan", "libcxx_tsan")
   libcxx_incdir = os.path.join(libcxx_path, "include", "c++", "v1")
   libcxx_libdir = os.path.join(libcxx_path, "lib")
-  libcxx_so = os.path.join(libcxx_libdir, "libc++.so")
+  if config.host_os == 'Darwin':
+    libcxx_so = os.path.join(libcxx_libdir, "libc++.dylib")
+    rpath_flag = '-Wl,-rpath,%s' % libcxx_so
+  else:
+    libcxx_so = os.path.join(libcxx_libdir, "libc++.so")
+    rpath_flag = '-Wl,-rpath=%s' % libcxx_so
   clang_tsan_cxxflags += ["-std=c++11",
                           "-I%s" % libcxx_incdir,
                           libcxx_so,
-                          "-Wl,-rpath=%s" % libcxx_libdir]
+                          rpath_flag]
 
 def build_invocation(compile_flags):
   return " " + " ".join([config.clang] + compile_flags) + " "