Index: test/asan/lit.cfg
===================================================================
--- test/asan/lit.cfg
+++ test/asan/lit.cfg
@@ -101,7 +101,18 @@
 config.substitutions.append( ("%clangxx ", build_invocation(target_cxxflags)) )
 config.substitutions.append( ("%clang_asan ", build_invocation(clang_asan_cflags)) )
 config.substitutions.append( ("%clangxx_asan ", build_invocation(clang_asan_cxxflags)) )
-config.substitutions.append( ("%shared_libasan", "libclang_rt.asan%s.so" % config.target_suffix))
+if config.host_os == 'Linux':
+  # FIXME: This should be an absolute path!
+  config.substitutions.append( ("%shared_libasan", "libclang_rt.asan%s.so" % config.target_suffix))
+elif config.host_os == 'Darwin':
+  shared_libasan_path = os.path.join(
+    config.compiler_rt_libdir,
+    'libclang_rt.asan_{}_dynamic.dylib'.format(
+      config.apple_platform
+    )
+  )
+  config.substitutions.append( ("%shared_libasan", shared_libasan_path) )
+
 if config.asan_dynamic:
   config.substitutions.append( ("%clang_asan_static ", build_invocation(clang_asan_static_cflags)) )
   config.substitutions.append( ("%clangxx_asan_static ", build_invocation(clang_asan_static_cxxflags)) )