diff --git a/flang/tools/tco/tco.cpp b/flang/tools/tco/tco.cpp
--- a/flang/tools/tco/tco.cpp
+++ b/flang/tools/tco/tco.cpp
@@ -21,6 +21,7 @@
 #include "mlir/Transforms/Passes.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/SourceMgr.h"