Fixed a 'not all control paths return a value' warning on MSVC builds

llvm-svn: 280917

clang/lib/CodeGen/CGVTables.cpp

@@ -529,6 +529,9 @@ llvm::Constant *CodeGenVTables::CreateVTableComponent(
   };
 
   switch (Component.getKind()) {
+  default:
+    llvm_unreachable("Unexpected vtable component kind");
+
   case VTableComponent::CK_VCallOffset:
     return OffsetConstant(Component.getVCallOffset());