diff --git a/CMakeLists.txt b/CMakeLists.txt
index 35379a2..ab35749 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -354,5 +354,5 @@
 set(BUG_REPORT_URL "http://llvm.org/bugs/" CACHE STRING
   "Default URL where bug reports are to be submitted.")
 
-option(CLANG_ORDER_FILE
-  "Order file to use when compiling clang in order to improve startup time." "")
+set(CLANG_ORDER_FILE "" CACHE FILEPATH
+  "Order file to use when compiling clang in order to improve startup time.")