let result frame =
match frame.result with
| Some x -> x
| None ->
match frame.return with
| Some typ ->
let tau = M.tau_of_logic_type (Ctype typ) in
let x = L.fresh "result" (Formula.Acsl(tau,Ctype typ)) in
frame.result <- Some x ; x
| None ->
Wp_parameters.fatal "Result type undefined"