MigrateDestinationRole

To migrate user role information into Drupal roles, uses the MigrateDestinationRole class:

$this->destination = new MigrateDestinationRole();
$this->addFieldMapping('name', 'source_role_name');
$this->addFieldMapping('weight', 'source_role_weight');

The constructor takes no arguments or options. Only two fields are available for mapping - the role name, and the weight (order it should be displayed in).