diff --git a/llvm/include/llvm/BinaryFormat/Magic.h b/llvm/include/llvm/BinaryFormat/Magic.h
index 64c687262f4a86..78227ddbe0954d 100644
--- a/llvm/include/llvm/BinaryFormat/Magic.h
+++ b/llvm/include/llvm/BinaryFormat/Magic.h
@@ -9,12 +9,12 @@
 #ifndef LLVM_BINARYFORMAT_MAGIC_H
 #define LLVM_BINARYFORMAT_MAGIC_H
 
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/Twine.h"
-
 #include <system_error>
 
 namespace llvm {
+class StringRef;
+class Twine;
+
 /// file_magic - An "enum class" enumeration of file types based on magic (the
 /// first N bytes of the file).
 struct file_magic {
diff --git a/llvm/lib/BinaryFormat/Magic.cpp b/llvm/lib/BinaryFormat/Magic.cpp
index bbcbbabededbed..61b1504e59b0af 100644
--- a/llvm/lib/BinaryFormat/Magic.cpp
+++ b/llvm/lib/BinaryFormat/Magic.cpp
@@ -7,7 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/BinaryFormat/Magic.h"
-
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/COFF.h"
 #include "llvm/BinaryFormat/ELF.h"
 #include "llvm/BinaryFormat/MachO.h"