fallback to classname when LM doesnt have config (#1334)

lm_eval/evaluator.py

@@ -158,11 +158,16 @@ def simple_evaluate(
     )
 
     if lm.rank == 0:
+        if isinstance(model, str):
+            model_name = model
+        elif hasattr(model, "config") and hasattr(model.config, "_name_or_path"):
+            model_name = model.config._name_or_path
+        else:
+            model_name = type(model).__name__
+
         # add info about the model and few shot config
         results["config"] = {
-            "model": model
-            if isinstance(model, str)
-            else model.model.config._name_or_path,
+            "model": model_name,
             "model_args": model_args,
             "batch_size": batch_size,
             "batch_sizes": list(lm.batch_sizes.values())