let offset_of_field f =
let rec acc sz l f =
match l with
| [] -> Wp_parameters.fatal "[offset_of_field] not found %s" f.fname
| fi::m ->
if Cil_datatype.Fieldinfo.equal f fi
then sz
else acc (F.i_add sz (sizeof (object_of fi.ftype))) m f
in
acc F.i_zero f.fcomp.cfields f