diff --git a/clangd/FileDistance.h b/clangd/FileDistance.h
index e7174bc..88bb30c 100644
--- a/clangd/FileDistance.h
+++ b/clangd/FileDistance.h
@@ -43,6 +43,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Path.h"