diff --git a/compiler/compiler_backend.h b/compiler/compiler_backend.h
index 5ebeef1..b20c125 100644
--- a/compiler/compiler_backend.h
+++ b/compiler/compiler_backend.h
@@ -40,7 +40,7 @@
     kPortable
   };
 
-  CompilerBackend(int warning)
+  explicit CompilerBackend(int warning)
       : maximum_compilation_time_before_warning_(warning) {}
 
   static CompilerBackend* Create(Kind kind);
@@ -93,4 +93,4 @@
 
 }  // namespace art
 
-#endif  // ART_COMPILER_DRIVER_COMPILER_BACKEND_H_
+#endif  // ART_COMPILER_COMPILER_BACKEND_H_