let userdef_signature frame _tused _pused =
let add (acc_vmem, acc_lab) (label, m) =
let acc_lab = match label with
| Clabels.LabelParam l -> Alloc l :: Mem l :: acc_lab
| _ -> Wp_parameters.fatal
"Unexpected statement label in user-defined symbol"
in
let vma = valloc_of_mem m in
let vmb = vbits_of_mem m in
vma::vmb::acc_vmem, acc_lab
in List.fold_left add ([], []) frame.memories