diff --git a/lib/Object/ObjectFile.cpp b/lib/Object/ObjectFile.cpp
index b14df9af64f..860c87be984 100644
--- a/lib/Object/ObjectFile.cpp
+++ b/lib/Object/ObjectFile.cpp
@@ -33,6 +33,8 @@ ObjectFile *ObjectFile::createObjectFile(MemoryBuffer *Object) {
   sys::LLVMFileType type = sys::IdentifyFileType(Object->getBufferStart(),
                                 static_cast<unsigned>(Object->getBufferSize()));
   switch (type) {
+    case sys::Unknown_FileType:
+      return 0;
     case sys::ELF_Relocatable_FileType:
     case sys::ELF_Executable_FileType:
     case sys::ELF_SharedObject_FileType:
@@ -52,7 +54,7 @@ ObjectFile *ObjectFile::createObjectFile(MemoryBuffer *Object) {
     case sys::COFF_FileType:
       return createCOFFObjectFile(Object);
     default:
-      llvm_unreachable("Unknown Object File Type");
+      llvm_unreachable("Unexpected Object File Type");
   }
 }
 
diff --git a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
index 06875005837..6041510e039 100644
--- a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
+++ b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
@@ -86,6 +86,11 @@ static void DumpInput(const StringRef &Filename) {
   }
 
   OwningPtr<ObjectFile> Obj(ObjectFile::createObjectFile(Buff.take()));
+  if (!Obj) {
+    errs() << Filename << ": Unknown object file format\n";
+    return;
+  }
+
   OwningPtr<DIContext> DICtx(DIContext::getDWARFContext(Obj.get()));
 
   if (Address == -1ULL) {