foreach $filepath (get_file_list($dir)) 
{
    my (%company_hist, @company_list, %reference_hist, @reference_list) ;
    my $twig = XML::Twig -> new(
        twig_roots => {
            company  => sub { push @company_list, $_[1]->{'att'}->{'code'} },
            ...
        }
    );