diff --git a/lib/Support/CMakeLists.txt b/lib/Support/CMakeLists.txt
index 7c8ce706b61..da80eaa07a3 100644
--- a/lib/Support/CMakeLists.txt
+++ b/lib/Support/CMakeLists.txt
@@ -25,6 +25,7 @@ add_llvm_library(LLVMSupport
   StringMap.cpp
   StringPool.cpp
   SystemUtils.cpp
+  Threading.cpp
   Timer.cpp
   Triple.cpp
   raw_ostream.cpp