Avoid gcc warning.

llvm-svn: 246811
diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 5385d2e..70a8760 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -38,6 +38,7 @@
   case ELF64LEKind:
     return getEMachine<ELF64LE>(B);
   }
+  llvm_unreachable("Invalid kind");
 }
 
 bool ELFFileBase::isCompatibleWith(const ELFFileBase &Other) const {