diff --git a/llvm/unittests/Debuginfod/HTTPServerTests.cpp b/llvm/unittests/Debuginfod/HTTPServerTests.cpp
--- a/llvm/unittests/Debuginfod/HTTPServerTests.cpp
+++ b/llvm/unittests/Debuginfod/HTTPServerTests.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/Debuginfod/HTTPClient.h"
 #include "llvm/Debuginfod/HTTPServer.h"
 #include "llvm/Support/Error.h"