[bart] add config.extra_pos_embeddings to facilitate reuse (#5190)

src/transformers/modeling_utils.py

@@ -2090,20 +2090,6 @@ class SequenceSummary(nn.Module):
         return output
 
 
-def create_position_ids_from_input_ids(input_ids, padding_idx):
-    """ Replace non-padding symbols with their position numbers. Position numbers begin at
-    padding_idx+1. Padding symbols are ignored. This is modified from fairseq's
-    `utils.make_positions`.
-
-    :param torch.Tensor x:
-    :return torch.Tensor:
-    """
-    # The series of casts and type-conversions here are carefully balanced to both work with ONNX export and XLA.
-    mask = input_ids.ne(padding_idx).int()
-    incremental_indices = torch.cumsum(mask, dim=1).type_as(mask) * mask
-    return incremental_indices.long() + padding_idx
-
-
 def prune_linear_layer(layer, index, dim=0):
     """ Prune a linear layer (a model parameters) to keep only entries in index.
         Return the pruned layer as a new layer with requires_grad=True.