diff --git a/lib/Support/TimeProfiler.cpp b/lib/Support/TimeProfiler.cpp
index f2ede75ccf9..47091221a78 100644
--- a/lib/Support/TimeProfiler.cpp
+++ b/lib/Support/TimeProfiler.cpp
@@ -19,6 +19,7 @@
 #include <algorithm>
 #include <cassert>
 #include <chrono>
+#include <mutex>
 #include <string>
 #include <vector>