diff --git a/lldb/test/API/tools/lldb-server/Makefile b/lldb/test/API/tools/lldb-server/Makefile
--- a/lldb/test/API/tools/lldb-server/Makefile
+++ b/lldb/test/API/tools/lldb-server/Makefile
@@ -1,6 +1,7 @@
 CFLAGS_EXTRAS := -D__STDC_LIMIT_MACROS -D__STDC_FORMAT_MACROS
 ENABLE_THREADS := YES
 CXX_SOURCES := main.cpp
-MAKE_DSYM :=NO
+MAKE_DSYM := NO
+CXXFLAGS_EXTRAS := -fmodules -fcxx-modules -fmodules-cache-path=$(THE_CLANG_MODULE_CACHE_DIR)
 
 include Makefile.rules