diff --git a/llvm/tools/llvm-readobj/llvm-readobj.h b/llvm/tools/llvm-readobj/llvm-readobj.h
index 54318b2..c89871f 100644
--- a/llvm/tools/llvm-readobj/llvm-readobj.h
+++ b/llvm/tools/llvm-readobj/llvm-readobj.h
@@ -22,6 +22,7 @@
 
   // Various helper functions.
   LLVM_ATTRIBUTE_NORETURN void reportError(Twine Msg);
+  void reportWarning(Twine Msg);
   void error(std::error_code EC);
   void error(llvm::Error EC);
   template <typename T> T error(llvm::Expected<T> &&E) {