(* Js_of_ocaml compiler
 * http://www.ocsigen.org/js_of_ocaml/
 * Copyright (C) 2010 Jérôme Vouillon
 * Laboratoire PPS - CNRS Université Paris Diderot
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, with linking exception;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *)

open Code

let expr s e =
  match e with
    Const _ | Constant _ ->
      e
  | Apply (f, l, n) ->
      Apply (s f, List.map (fun x -> s x) l, n)
  | Block (n, a) ->
      Block (n, Array.map (fun x -> s x) a)
  | Field (x, n) ->
      Field (s x, n)
  | Closure (l, pc) ->
      Closure (l, pc)
  | Prim (p, l) ->
      Prim (p, List.map (fun x -> match x with Pv x -> Pv (s x) | Pc _ -> x) l)

let instr s i =
  match i with
    Let (x, e) ->
      Let (x, expr s e)
  | Set_field (x, n, y) ->
      Set_field (s x, n, s y)
  | Offset_ref (x, n) ->
      Offset_ref (s x, n)
  | Array_set (x, y, z) ->
      Array_set (s x, s y, s z)

let instrs s l = List.map (fun i -> instr s i) l

let subst_cont s (pc, arg) = (pc, List.map (fun x -> s x) arg)

let last s l =
  match l with
    Stop ->
      l
  | Branch cont ->
      Branch (subst_cont s cont)
  | Pushtrap (cont1, x, cont2, pc) ->
      Pushtrap (subst_cont s cont1, x, subst_cont s cont2, pc)
  | Return x ->
      Return (s x)
  | Raise x ->
      Raise (s x)
  | Cond (c, x, cont1, cont2) ->
      Cond (c, s x, subst_cont s cont1, subst_cont s cont2)
  | Switch (x, a1, a2) ->
      Switch (s x,
              Array.map (fun cont -> subst_cont s cont) a1,
              Array.map (fun cont -> subst_cont s cont) a2)
  | Poptrap cont ->
      Poptrap (subst_cont s cont)

let program s (pc, blocks, free_pc) =
  let blocks =
    AddrMap.map
      (fun block ->
         { params = block.params;
           handler = Util.opt_map
                       (fun (x, cont) -> (x, subst_cont s cont)) block.handler;
           body = instrs s block.body;
           branch = last s block.branch }) blocks
  in
  (pc, blocks, free_pc)

(****)

let from_array s =
  fun x -> match s.(Var.idx x) with Some y -> y | None -> x

(****)

let rec build_mapping params args =
  match params, args with
    x :: params, y :: args ->
      VarMap.add x y (build_mapping params args)
  | [], _ ->
      VarMap.empty
  | _ ->
      assert false

let from_map m =
  fun x -> try VarMap.find x m with Not_found -> x