open Batteries
open Rtl
open Linear
open Prog
open Utils


let succs_of_rtl_instr (i: rtl_instr) =
  match i with
  | Rtl.Rbranch (_, _, _, s1) -> [s1]
  | Rtl.Rjmp s -> [s]
  | _ -> []

let rec succs_of_rtl_instrs il : int list =
  List.concat (List.map succs_of_rtl_instr il)

(* effectue un tri topologique des blocs.  *)
let sort_blocks (nodes: (int, rtl_instr list) Hashtbl.t) entry =
  let rec add_block order n =
   (* TODO *)
   List.of_enum (Hashtbl.keys nodes)
  in
  add_block [] entry


(* Supprime les jumps inutiles (Jmp à un label défini juste en dessous). *)
let rec remove_useless_jumps (l: rtl_instr list) =
   (* TODO *)
   l


(* Remove labels that are never jumped to. *)
let remove_useless_labels (l: rtl_instr list) =
   (* TODO *)
   l

let linear_of_rtl_fun
    ({ rtlfunargs; rtlfunbody; rtlfunentry; rtlfuninfo }: rtl_fun) =
  let block_order = sort_blocks rtlfunbody rtlfunentry in
  let linearinstrs =
    List.fold_left (fun l n ->
        match Hashtbl.find_option rtlfunbody n with
        | None -> l
        | Some li -> l @ Rlabel(n) :: li
      ) [] block_order in
  { linearfunargs = rtlfunargs;
    linearfunbody =
      linearinstrs |> remove_useless_jumps |> remove_useless_labels;
    linearfuninfo = rtlfuninfo;
  }

let linear_of_rtl_gdef = function
    Gfun f -> Gfun (linear_of_rtl_fun f)

let linear_of_rtl r =
  assoc_map linear_of_rtl_gdef r