lam.ml

(* Copyright (C) 2018 - Hongbo Zhang, Authors of ReScript
 *
 * 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * In addition to the permissions granted to you by the LGPL, you may combine
 * or link a "work that uses the Library" with a publicly distributed version
 * of this file to produce a combined library or application, then distribute
 * that combined work under the terms of your choosing, with no requirement
 * to comply with the obligations normally placed on you by section 4 of the
 * LGPL version 3 (or the corresponding section of a later version of the LGPL
 * should you choose to use a 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. *)

type ident = Ident.t
type apply_status = App_na | App_infer_full | App_uncurry

type ap_info = {
  ap_loc : Location.t;
  ap_inlined : Lambda.inline_attribute;
  ap_status : apply_status;
}

module Types = struct
  type lambda_switch = {
    sw_consts_full : bool;
    (* TODO: refine its representation *)
    sw_consts : (int * t) list;
    sw_blocks_full : bool;
    sw_blocks : (int * t) list;
    sw_failaction : t option;
    sw_names : Lambda.switch_names option;
  }

  and lfunction = {
    arity : int;
    params : ident list;
    body : t;
    attr : Lambda.function_attribute;
  }

  (*
     Invariant:
     length (sw_consts) <= sw_consts_full
     when length (sw_consts) >= sw_consts_full -> true
     Note that failaction would appear in both
      {[
        match x with
        | ..
          | ..
            | _ -> 2
      ]}
      since compiler would first test [x] is a const pointer
      or not then the [default] applies to each branch.

      In most cases: {[
        let sw =
          {sw_consts_full = cstr.cstr_consts; sw_consts = consts;
           sw_blocks_full = cstr.cstr_nonconsts; sw_blocks = nonconsts;
           sw_failaction = None} in
      ]}

      but there are some edge cases (see https://caml.inria.fr/mantis/view.php?id=6033)
      one predicate used is
      {[
        (sw.sw_consts_full - List.length sw.sw_consts) +
        (sw.sw_blocks_full - List.length sw.sw_blocks) > 1
      ]}
      if [= 1] with [some fail] -- called once
      if [= 0] could not have [some fail]
  *)
  and prim_info = {
    primitive : Lam_primitive.t;
    args : t list;
    loc : Location.t;
  }

  and apply = { ap_func : t; ap_args : t list; ap_info : ap_info }

  and t =
    | Lvar of ident
    | Lglobal_module of ident
    | Lconst of Lam_constant.t
    | Lapply of apply
    | Lfunction of lfunction
    | Llet of Lam_compat.let_kind * ident * t * t
    | Lletrec of (ident * t) list * t
    | Lprim of prim_info
    | Lswitch of t * lambda_switch
    | Lstringswitch of t * (string * t) list * t option
    | Lstaticraise of int * t list
    | Lstaticcatch of t * (int * ident list) * t
    | Ltrywith of t * ident * t
    | Lifthenelse of t * t * t
    | Lsequence of t * t
    | Lwhile of t * t
    | Lfor of ident * t * t * Asttypes.direction_flag * t
    | Lassign of ident * t
  (* | Lsend of Lam_compat.meth_kind * t * t * t list * Location.t *)
end

module X = struct
  type lambda_switch = Types.lambda_switch = {
    sw_consts_full : bool;
    sw_consts : (int * t) list;
    sw_blocks_full : bool;
    sw_blocks : (int * t) list;
    sw_failaction : t option;
    sw_names : Lambda.switch_names option;
  }

  and prim_info = Types.prim_info = {
    primitive : Lam_primitive.t;
    args : t list;
    loc : Location.t;
  }

  and apply = Types.apply = { ap_func : t; ap_args : t list; ap_info : ap_info }

  and lfunction = Types.lfunction = {
    arity : int;
    params : ident list;
    body : t;
    attr : Lambda.function_attribute;
  }

  and t = Types.t =
    | Lvar of ident
    | Lglobal_module of ident
    | Lconst of Lam_constant.t
    | Lapply of apply
    | Lfunction of lfunction
    | Llet of Lam_compat.let_kind * ident * t * t
    | Lletrec of (ident * t) list * t
    | Lprim of prim_info
    | Lswitch of t * lambda_switch
    | Lstringswitch of t * (string * t) list * t option
    | Lstaticraise of int * t list
    | Lstaticcatch of t * (int * ident list) * t
    | Ltrywith of t * ident * t
    | Lifthenelse of t * t * t
    | Lsequence of t * t
    | Lwhile of t * t
    | Lfor of ident * t * t * Asttypes.direction_flag * t
    | Lassign of ident * t
  (* | Lsend of Lam_compat.meth_kind * t * t * t list * Location.t *)
end

include Types

(** apply [f] to direct successor which has type [Lam.t] *)

let inner_map (l : t) (f : t -> X.t) : X.t =
  match l with
  | Lvar (_ : ident) | Lconst (_ : Lam_constant.t) -> ((* Obj.magic *) l : X.t)
  | Lapply { ap_func; ap_args; ap_info } ->
      let ap_func = f ap_func in
      let ap_args = Ext_list.map ap_args f in
      Lapply { ap_func; ap_args; ap_info }
  | Lfunction { body; arity; params; attr } ->
      let body = f body in
      Lfunction { body; arity; params; attr }
  | Llet (str, id, arg, body) ->
      let arg = f arg in
      let body = f body in
      Llet (str, id, arg, body)
  | Lletrec (decl, body) ->
      let body = f body in
      let decl = Ext_list.map_snd decl f in
      Lletrec (decl, body)
  | Lglobal_module _ -> (l : X.t)
  | Lprim { args; primitive; loc } ->
      let args = Ext_list.map args f in
      Lprim { args; primitive; loc }
  | Lswitch
      ( arg,
        {
          sw_consts;
          sw_consts_full;
          sw_blocks;
          sw_blocks_full;
          sw_failaction;
          sw_names;
        } ) ->
      let arg = f arg in
      let sw_consts = Ext_list.map_snd sw_consts f in
      let sw_blocks = Ext_list.map_snd sw_blocks f in
      let sw_failaction = Ext_option.map sw_failaction f in
      Lswitch
        ( arg,
          {
            sw_consts;
            sw_blocks;
            sw_failaction;
            sw_blocks_full;
            sw_consts_full;
            sw_names;
          } )
  | Lstringswitch (arg, cases, default) ->
      let arg = f arg in
      let cases = Ext_list.map_snd cases f in
      let default = Ext_option.map default f in
      Lstringswitch (arg, cases, default)
  | Lstaticraise (id, args) ->
      let args = Ext_list.map args f in
      Lstaticraise (id, args)
  | Lstaticcatch (e1, vars, e2) ->
      let e1 = f e1 in
      let e2 = f e2 in
      Lstaticcatch (e1, vars, e2)
  | Ltrywith (e1, exn, e2) ->
      let e1 = f e1 in
      let e2 = f e2 in
      Ltrywith (e1, exn, e2)
  | Lifthenelse (e1, e2, e3) ->
      let e1 = f e1 in
      let e2 = f e2 in
      let e3 = f e3 in
      Lifthenelse (e1, e2, e3)
  | Lsequence (e1, e2) ->
      let e1 = f e1 in
      let e2 = f e2 in
      Lsequence (e1, e2)
  | Lwhile (e1, e2) ->
      let e1 = f e1 in
      let e2 = f e2 in
      Lwhile (e1, e2)
  | Lfor (v, e1, e2, dir, e3) ->
      let e1 = f e1 in
      let e2 = f e2 in
      let e3 = f e3 in
      Lfor (v, e1, e2, dir, e3)
  | Lassign (id, e) ->
      let e = f e in
      Lassign (id, e)
(* | Lsend (k, met, obj, args, loc) ->
   let met = f met in
   let obj = f obj in
   let args = Ext_list.map args f in
   Lsend(k,met,obj,args,loc) *)

exception Not_simple_form

(**


   [is_eta_conversion_exn params inner_args outer_args]
   case 1:
   {{
    (fun params -> wrap (primitive (inner_args)) args
   }}
   when [inner_args] are the same as [params], it can be simplified as
   [wrap (primitive args)]

    where [wrap] used to be simple instructions
    Note that [external] functions are forced to do eta-conversion
    when combined with [|>] operator, we need to make sure beta-reduction
    is applied though since `[@variadic]` needs such guarantee.
    Since `[@variadic] is the tail position
*)
let rec is_eta_conversion_exn params inner_args outer_args : t list =
  match (params, inner_args, outer_args) with
  | x :: xs, Lvar y :: ys, r :: rest when Ident.same x y ->
      r :: is_eta_conversion_exn xs ys rest
  | ( x :: xs,
      Lprim ({ primitive = Pjs_fn_make _; args = [ Lvar y ] } as p) :: ys,
      r :: rest )
    when Ident.same x y ->
      Lprim { p with args = [ r ] } :: is_eta_conversion_exn xs ys rest
  | [], [], [] -> []
  | _, _, _ -> raise_notrace Not_simple_form

(** FIXME: more robust inlining check later, we should inline it before we add stub code*)
let rec apply fn args (ap_info : ap_info) : t =
  match fn with
  | Lfunction
      {
        params;
        body =
          Lprim
            {
              primitive =
                ( Pundefined_to_opt | Pnull_to_opt | Pnull_undefined_to_opt
                | Pis_null | Pis_null_undefined | Pjs_typeof ) as wrap;
              args =
                [
                  Lprim ({ primitive = _; args = inner_args } as primitive_call);
                ];
            };
      } -> (
      match is_eta_conversion_exn params inner_args args with
      | args ->
          let loc = ap_info.ap_loc in
          Lprim
            {
              primitive = wrap;
              args = [ Lprim { primitive_call with args; loc } ];
              loc;
            }
      | exception Not_simple_form ->
          Lapply { ap_func = fn; ap_args = args; ap_info })
  | Lfunction
      {
        params;
        body = Lprim ({ primitive = _; args = inner_args } as primitive_call);
      } -> (
      match is_eta_conversion_exn params inner_args args with
      | args -> Lprim { primitive_call with args; loc = ap_info.ap_loc }
      | exception _ -> Lapply { ap_func = fn; ap_args = args; ap_info })
  | Lfunction
      {
        params;
        body =
          Lsequence
            ( Lprim ({ primitive = _; args = inner_args } as primitive_call),
              (Lconst _ as const) );
      } -> (
      match is_eta_conversion_exn params inner_args args with
      | args ->
          Lsequence
            (Lprim { primitive_call with args; loc = ap_info.ap_loc }, const)
      | exception _ ->
          Lapply { ap_func = fn; ap_args = args; ap_info }
          (* | Lfunction {params;body} when Ext_list.same_length params args ->
              Ext_list.fold_right2 (fun p arg acc ->
                Llet(Strict,p,arg,acc)
              ) params args body *)
          (* TODO: more rigirous analysis on [let_kind] *))
  | Llet (kind, id, e, (Lfunction _ as fn)) ->
      Llet (kind, id, e, apply fn args ap_info)
  (* | Llet (kind0, id0, e0, Llet (kind,id, e, (Lfunction _ as fn))) ->
     Llet(kind0,id0,e0,Llet (kind, id, e, apply fn args loc status)) *)
  | _ -> Lapply { ap_func = fn; ap_args = args; ap_info }

let rec eq_approx (l1 : t) (l2 : t) =
  match l1 with
  | Lglobal_module i1 -> (
      match l2 with Lglobal_module i2 -> Ident.same i1 i2 | _ -> false)
  | Lvar i1 -> ( match l2 with Lvar i2 -> Ident.same i1 i2 | _ -> false)
  | Lconst c1 -> (
      match l2 with Lconst c2 -> Lam_constant.eq_approx c1 c2 | _ -> false)
  | Lapply app1 -> (
      match l2 with
      | Lapply app2 ->
          eq_approx app1.ap_func app2.ap_func
          && eq_approx_list app1.ap_args app2.ap_args
      | _ -> false)
  | Lifthenelse (a, b, c) -> (
      match l2 with
      | Lifthenelse (a0, b0, c0) ->
          eq_approx a a0 && eq_approx b b0 && eq_approx c c0
      | _ -> false)
  | Lsequence (a, b) -> (
      match l2 with
      | Lsequence (a0, b0) -> eq_approx a a0 && eq_approx b b0
      | _ -> false)
  | Lwhile (p, b) -> (
      match l2 with
      | Lwhile (p0, b0) -> eq_approx p p0 && eq_approx b b0
      | _ -> false)
  | Lassign (v0, l0) -> (
      match l2 with
      | Lassign (v1, l1) -> Ident.same v0 v1 && eq_approx l0 l1
      | _ -> false)
  | Lstaticraise (id, ls) -> (
      match l2 with
      | Lstaticraise (id1, ls1) -> id = id1 && eq_approx_list ls ls1
      | _ -> false)
  | Lprim info1 -> (
      match l2 with
      | Lprim info2 ->
          Lam_primitive.eq_primitive_approx info1.primitive info2.primitive
          && eq_approx_list info1.args info2.args
      | _ -> false)
  | Lstringswitch (arg, patterns, default) -> (
      match l2 with
      | Lstringswitch (arg2, patterns2, default2) ->
          eq_approx arg arg2 && eq_option default default2
          && Ext_list.for_all2_no_exn patterns patterns2
               (fun ((k : string), v) (k2, v2) -> k = k2 && eq_approx v v2)
      | _ -> false)
  | Lfunction _
  | Llet (_, _, _, _)
  | Lletrec _ | Lswitch _ | Lstaticcatch _ | Ltrywith _
  | Lfor (_, _, _, _, _) ->
      false

and eq_option l1 l2 =
  match l1 with
  | None -> l2 = None
  | Some l1 -> ( match l2 with Some l2 -> eq_approx l1 l2 | None -> false)

and eq_approx_list ls ls1 = Ext_list.for_all2_no_exn ls ls1 eq_approx

let switch lam (lam_switch : lambda_switch) : t =
  match lam with
  | Lconst (Const_int { i }) ->
      Ext_list.assoc_by_int lam_switch.sw_consts (Int32.to_int i)
        lam_switch.sw_failaction
  | Lconst (Const_block (i, _, _)) ->
      Ext_list.assoc_by_int lam_switch.sw_blocks i lam_switch.sw_failaction
  | _ -> Lswitch (lam, lam_switch)

let stringswitch (lam : t) cases default : t =
  match lam with
  | Lconst (Const_string { s; unicode = false }) ->
      Ext_list.assoc_by_string cases s default
  | _ -> Lstringswitch (lam, cases, default)

let true_ : t = Lconst Const_js_true
let false_ : t = Lconst Const_js_false
let unit : t = Lconst Const_js_undefined

let rec seq (a : t) b : t =
  match a with
  | Lprim { primitive = Pmakeblock _; args = x :: xs } ->
      seq (Ext_list.fold_left xs x seq) b
  | Lprim
      {
        primitive = Pnull_to_opt | Pundefined_to_opt | Pnull_undefined_to_opt;
        args = [ a ];
      } ->
      seq a b
  | _ -> Lsequence (a, b)

let var id : t = Lvar id
let global_module id = Lglobal_module id
let const ct : t = Lconst ct

let function_ ~attr ~arity ~params ~body : t =
  Lfunction { arity; params; body; attr }

let let_ kind id e body : t = Llet (kind, id, e, body)
let letrec bindings body : t = Lletrec (bindings, body)
let while_ a b : t = Lwhile (a, b)
let try_ body id handler : t = Ltrywith (body, id, handler)
let for_ v e1 e2 dir e3 : t = Lfor (v, e1, e2, dir, e3)
let assign v l : t = Lassign (v, l)
let staticcatch a b c : t = Lstaticcatch (a, b, c)
let staticraise a b : t = Lstaticraise (a, b)

module Lift = struct
  let int i : t = Lconst (Const_int { i; comment = None })

  (* let int32 i : t =
     Lconst ((Const_int32 i)) *)

  let bool b = if b then true_ else false_

  (* ATTENTION: [float, nativeint] constant propogaton is not done
     yet , due to cross platform problem
  *)
  (* let float b  : t =
     Lconst ((Const_float b)) *)

  (* let nativeint b : t =
     Lconst ((Const_nativeint b)) *)

  let int64 b : t = Lconst (Const_int64 b)
  let string s : t = Lconst (Const_string { s; unicode = false })
  let char b : t = Lconst (Const_char b)
end

let prim ~primitive:(prim : Lam_primitive.t) ~args loc : t =
  let default () : t = Lprim { primitive = prim; args; loc } in
  match args with
  | [ Lconst a ] -> (
      match (prim, a) with
      | Pnegint, Const_int { i } -> Lift.int (Int32.neg i)
      (* | Pfloatofint, ( (Const_int a)) *)
      (*   -> Lift.float (float_of_int a) *)
      | Pintoffloat, Const_float a ->
          Lift.int (Int32.of_float (float_of_string a))
      (* | Pnegfloat -> Lift.float (-. a) *)
      (* | Pabsfloat -> Lift.float (abs_float a) *)
      | Pstringlength, Const_string { s; unicode = false } ->
          Lift.int (Int32.of_int (String.length s))
      (* | Pnegbint Pnativeint, ( (Const_nativeint i)) *)
      (*   ->   *)
      (*   Lift.nativeint (Nativeint.neg i) *)
      | Pnegint64, Const_int64 a -> Lift.int64 (Int64.neg a)
      | Pnot, Const_js_true -> false_
      | Pnot, Const_js_false -> true_
      | _ -> default ())
  | [ Lconst a; Lconst b ] -> (
      match (prim, a, b) with
      | Pint64comp cmp, Const_int64 a, Const_int64 b ->
          Lift.bool (Lam_compat.cmp_int64 cmp a b)
      | Pintcomp cmp, Const_int a, Const_int b ->
          Lift.bool (Lam_compat.cmp_int32 cmp a.i b.i)
      | Pfloatcomp cmp, Const_float a, Const_float b ->
          (* FIXME: could raise? *)
          Lift.bool
            (Lam_compat.cmp_float cmp (float_of_string a) (float_of_string b))
      | Pintcomp ((Ceq | Cneq) as op), Const_pointer a, Const_pointer b ->
          Lift.bool
            (match op with
            | Ceq -> a = (b : string)
            | Cneq -> a <> b
            | _ -> assert false)
      | ( ( Paddint | Psubint | Pmulint | Pdivint | Pmodint | Pandint | Porint
          | Pxorint | Plslint | Plsrint | Pasrint ),
          Const_int { i = aa },
          Const_int { i = bb } ) -> (
          (* WE SHOULD keep it as [int], to preserve types *)
          let int_ = Lift.int in
          match prim with
          | Paddint -> int_ (Int32.add aa bb)
          | Psubint -> int_ (Int32.sub aa bb)
          | Pmulint -> int_ (Int32.mul aa bb)
          | Pdivint -> if bb = 0l then default () else int_ (Int32.div aa bb)
          | Pmodint -> if bb = 0l then default () else int_ (Int32.rem aa bb)
          | Pandint -> int_ (Int32.logand aa bb)
          | Porint -> int_ (Int32.logor aa bb)
          | Pxorint -> int_ (Int32.logxor aa bb)
          | Plslint -> int_ (Int32.shift_left aa (Int32.to_int bb))
          | Plsrint -> int_ (Int32.shift_right_logical aa (Int32.to_int bb))
          | Pasrint -> int_ (Int32.shift_right aa (Int32.to_int bb))
          | _ -> default ())
      | ( ( Paddint64 | Psubint64 | Pmulint64 | Pdivint64 | Pmodint64
          | Pandint64 | Porint64 | Pxorint64 ),
          Const_int64 aa,
          Const_int64 bb ) -> (
          match prim with
          | Paddint64 -> Lift.int64 (Int64.add aa bb)
          | Psubint64 -> Lift.int64 (Int64.sub aa bb)
          | Pmulint64 -> Lift.int64 (Int64.mul aa bb)
          | Pdivint64 -> (
              try Lift.int64 (Int64.div aa bb) with _ -> default ())
          | Pmodint64 -> (
              try Lift.int64 (Int64.rem aa bb) with _ -> default ())
          | Pandint64 -> Lift.int64 (Int64.logand aa bb)
          | Porint64 -> Lift.int64 (Int64.logor aa bb)
          | Pxorint64 -> Lift.int64 (Int64.logxor aa bb)
          | _ -> default ())
      | Plslint64, Const_int64 aa, Const_int { i = b } ->
          Lift.int64 (Int64.shift_left aa (Int32.to_int b))
      | Plsrint64, Const_int64 aa, Const_int { i = b } ->
          Lift.int64 (Int64.shift_right_logical aa (Int32.to_int b))
      | Pasrint64, Const_int64 aa, Const_int { i = b } ->
          Lift.int64 (Int64.shift_right aa (Int32.to_int b))
      | Psequand, Const_js_false, (Const_js_true | Const_js_false) -> false_
      | Psequand, Const_js_true, Const_js_true -> true_
      | Psequand, Const_js_true, Const_js_false -> false_
      | Psequor, Const_js_true, (Const_js_true | Const_js_false) -> true_
      | Psequor, Const_js_false, Const_js_true -> true_
      | Psequor, Const_js_false, Const_js_false -> false_
      | ( Pstringadd,
          Const_string { s = a; unicode = false },
          Const_string { s = b; unicode = false } ) ->
          Lift.string (a ^ b)
      | ( (Pstringrefs | Pstringrefu),
          Const_string { s = a; unicode = false },
          Const_int { i = b } ) -> (
          try Lift.char (Char.code (String.get a (Int32.to_int b))) with _ -> default ())
      | _ -> default ())
  | _ -> (
      match prim with
      | Pmakeblock (_size, Blk_module fields, _) -> (
          let rec aux fields args (var : Ident.t) i =
            match (fields, args) with
            | [], [] -> true
            | ( f :: fields,
                Lprim
                  {
                    primitive = Pfield (pos, Fld_module { name = f1 });
                    args = [ (Lglobal_module v1 | Lvar v1) ];
                  }
                :: args ) ->
                pos = i && f = f1 && Ident.same var v1
                && aux fields args var (i + 1)
            | _, _ -> false
          in
          match (fields, args) with
          | ( field1 :: rest,
              Lprim
                {
                  primitive = Pfield (pos, Fld_module { name = f1 });
                  args = [ ((Lglobal_module v1 | Lvar v1) as lam) ];
                }
              :: args1 ) ->
              if pos = 0 && field1 = f1 && aux rest args1 v1 1 then lam
              else default ()
          | _ -> default ())
      (* In this level, include is already expanded, so that
         {[
           { x0 : y0 ; x1 : y1 }
         ]}
         such module x can indeed be replaced by module y
      *)
      | _ -> default ())

let not_ loc x : t =
  match x with
  | Lprim ({ primitive = Pintcomp Cneq } as prim) ->
      Lprim { prim with primitive = Pintcomp Ceq }
  | _ -> prim ~primitive:Pnot ~args:[ x ] loc

let has_boolean_type (x : t) =
  match x with
  | Lprim
      {
        primitive =
          ( Pnot | Psequand | Psequor | Pisout _ | Pintcomp _ | Pis_not_none
          | Pfloatcomp _
          | Pccall { prim_name = "caml_string_equal" | "caml_string_notequal" }
            );
        loc;
      } ->
      Some loc
  | _ -> None

(** [complete_range sw_consts 0 7]
    is complete with [0,1,.. 7]
*)
let rec complete_range (sw_consts : (int * _) list) ~(start : int) ~finish =
  match sw_consts with
  | [] -> finish < start
  | (i, _) :: rest ->
      start <= finish && i = start
      && complete_range rest ~start:(start + 1) ~finish

let rec eval_const_as_bool (v : Lam_constant.t) : bool =
  match v with
  | Const_int { i = x } -> x <> 0l
  | Const_char x -> x <> 0
  | Const_int64 x -> x <> 0L
  | Const_js_false | Const_js_null | Const_module_alias | Const_js_undefined ->
      false
  | Const_js_true | Const_string _ | Const_pointer _ | Const_float _
  | Const_block _ | Const_float_array _ ->
      true
  | Const_some b -> eval_const_as_bool b

let if_ (a : t) (b : t) (c : t) : t =
  match a with
  | Lconst v -> if eval_const_as_bool v then b else c
  | _ -> (
      match (b, c) with
      | _, Lconst (Const_int { comment = Pt_assertfalse }) ->
          seq a b (* TODO: we could customize more cases *)
      | Lconst (Const_int { comment = Pt_assertfalse }), _ -> seq a c
      | Lconst Const_js_true, Lconst Const_js_false ->
          if has_boolean_type a != None then a else Lifthenelse (a, b, c)
      | Lconst Const_js_false, Lconst Const_js_true -> (
          match has_boolean_type a with
          | Some loc -> not_ loc a
          | None -> Lifthenelse (a, b, c))
      | Lprim { primitive = Praise }, _ -> (
          match c with
          | Lconst _ -> Lifthenelse (a, b, c)
          | _ -> seq (Lifthenelse (a, b, unit)) c)
      | _ -> (
          match a with
          | Lprim
              {
                primitive = Pisout off;
                args = [ Lconst (Const_int { i = range }); Lvar xx ];
              } -> (
              let range = Int32.to_int range in
              match c with
              | Lswitch
                  ( (Lvar yy as switch_arg),
                    ({
                       sw_blocks = [];
                       sw_blocks_full = true;
                       sw_consts;
                       sw_consts_full = _;
                       sw_failaction = None;
                     } as body) )
                when Ident.same xx yy
                     && complete_range sw_consts ~start:(-off)
                          ~finish:(range - off) ->
                  Lswitch
                    ( switch_arg,
                      {
                        body with
                        sw_failaction = Some b;
                        sw_consts_full = false;
                      } )
              | _ -> Lifthenelse (a, b, c))
          | Lprim { primitive = Pisint; args = [ Lvar i ]; _ } -> (
              match b with
              | Lifthenelse
                  ( Lprim
                      { primitive = Pintcomp Ceq; args = [ Lvar j; Lconst _ ] },
                    _,
                    b_f )
                when Ident.same i j && eq_approx b_f c ->
                  b
              | Lprim { primitive = Pintcomp Ceq; args = [ Lvar j; Lconst _ ] }
                when Ident.same i j && eq_approx false_ c ->
                  b
              | Lifthenelse
                  ( Lprim
                      ({
                         primitive = Pintcomp Cneq;
                         args = [ Lvar j; Lconst _ ];
                       } as b_pred),
                    b_t,
                    b_f )
                when Ident.same i j && eq_approx b_t c ->
                  Lifthenelse
                    (Lprim { b_pred with primitive = Pintcomp Ceq }, b_f, b_t)
              | Lprim
                  {
                    primitive = Pintcomp Cneq;
                    args = [ Lvar j; Lconst _ ] as args;
                    loc;
                  }
              | Lprim
                  {
                    primitive = Pnot;
                    args =
                      [
                        Lprim
                          {
                            primitive = Pintcomp Ceq;
                            args = [ Lvar j; Lconst _ ] as args;
                            loc;
                          };
                      ];
                  }
                when Ident.same i j && eq_approx true_ c ->
                  Lprim { primitive = Pintcomp Cneq; args; loc }
              | _ -> Lifthenelse (a, b, c))
          | _ -> Lifthenelse (a, b, c)))

(* TODO: the smart constructor is not exploited yet*)
(* [l || r ] *)
let sequor l r = if_ l true_ r

(** [l && r ] *)
let sequand l r = if_ l r false_

(******************************************************************)
(* only [handle_bs_non_obj_ffi] will be used outside *)
(*
   [no_auto_uncurried_arg_types xs]
   check if the FFI have @uncurry attribute.
   if it does not we wrap it in a nomral way otherwise
*)
let rec no_auto_uncurried_arg_types (xs : External_arg_spec.params) =
  match xs with
  | [] -> true
  | { arg_type = Fn_uncurry_arity _ } :: _ -> false
  | _ :: xs -> no_auto_uncurried_arg_types xs

let result_wrap loc (result_type : External_ffi_types.return_wrapper) result =
  match result_type with
  | Return_replaced_with_unit -> seq result unit
  | Return_null_to_opt -> prim ~primitive:Pnull_to_opt ~args:[ result ] loc
  | Return_null_undefined_to_opt ->
      prim ~primitive:Pnull_undefined_to_opt ~args:[ result ] loc
  | Return_undefined_to_opt ->
      prim ~primitive:Pundefined_to_opt ~args:[ result ] loc
  | Return_unset | Return_identity -> result

let rec transform_uncurried_arg_type loc (arg_types : External_arg_spec.params)
    (args : t list) =
  match (arg_types, args) with
  | { arg_type = Fn_uncurry_arity n; arg_label } :: xs, y :: ys ->
      let o_arg_types, o_args = transform_uncurried_arg_type loc xs ys in
      ( { External_arg_spec.arg_type = Nothing; arg_label } :: o_arg_types,
        prim ~primitive:(Pjs_fn_make n) ~args:[ y ] loc :: o_args )
  | x :: xs, y :: ys -> (
      match x with
      | { arg_type = Arg_cst _ } ->
          let o_arg_types, o_args = transform_uncurried_arg_type loc xs args in
          (x :: o_arg_types, o_args)
      | _ ->
          let o_arg_types, o_args = transform_uncurried_arg_type loc xs ys in
          (x :: o_arg_types, y :: o_args))
  | ([], [] | _ :: _, [] | [], _ :: _) as ok -> ok

let handle_bs_non_obj_ffi (arg_types : External_arg_spec.params)
    (result_type : External_ffi_types.return_wrapper) ffi args loc prim_name =
  if no_auto_uncurried_arg_types arg_types then
    result_wrap loc result_type
      (prim ~primitive:(Pjs_call { prim_name; arg_types; ffi }) ~args loc)
  else
    let n_arg_types, n_args = transform_uncurried_arg_type loc arg_types args in
    result_wrap loc result_type
      (prim
         ~primitive:(Pjs_call { prim_name; arg_types = n_arg_types; ffi })
         ~args:n_args loc)