sig
type data
val clear : unit -> unit
val mem : int -> bool
val find : int -> Dataflow.StmtStartData.data
val replace : int -> Dataflow.StmtStartData.data -> unit
val add : int -> Dataflow.StmtStartData.data -> unit
val iter : (int -> Dataflow.StmtStartData.data -> unit) -> unit
val length : unit -> int
end