diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index d422312..b88d2d8 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -962,6 +962,7 @@
                        "format: not implemented.");
     break;
   }
+  llvm_unreachable("Unknown ObjectFormatType");
 }
 
 MCSection *