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(* ----------------------------------------------------------------------------
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 * SchedMCore - A MultiCore Scheduling Framework
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 * Copyright (C) 2009-2013, ONERA, Toulouse, FRANCE - LIFL, Lille, FRANCE
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 * Copyright (C) 2012-2013, INPT, Toulouse, FRANCE
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 *
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 * This file is part of Prelude
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 *
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 * Prelude is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public License
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 * as published by the Free Software Foundation ; either version 2 of
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 * the License, or (at your option) any later version.
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 *
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 * Prelude is distributed in the hope that it will be useful, but
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 * WITHOUT ANY WARRANTY ; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this program ; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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 * USA
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 *---------------------------------------------------------------------------- *)
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(* This module is used for the lustre to C compiler *)
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open Utils
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open LustreSpec
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open Corelang
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(* open Clocks *)
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open Format
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let expr_true loc ck =
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{ expr_tag = Utils.new_tag ();
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  expr_desc = Expr_const (Const_tag tag_true);
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  expr_type = Type_predef.type_bool;
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  expr_clock = ck;
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  expr_delay = Delay.new_var ();
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  expr_annot = None;
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  expr_loc = loc }
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let expr_false loc ck =
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{ expr_tag = Utils.new_tag ();
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  expr_desc = Expr_const (Const_tag tag_false);
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  expr_type = Type_predef.type_bool;
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  expr_clock = ck;
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  expr_delay = Delay.new_var ();
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  expr_annot = None;
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  expr_loc = loc }
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let expr_once loc ck =
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 { expr_tag = Utils.new_tag ();
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  expr_desc = Expr_arrow (expr_true loc ck, expr_false loc ck);
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  expr_type = Type_predef.type_bool;
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  expr_clock = ck;
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  expr_delay = Delay.new_var ();
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  expr_annot = None;
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  expr_loc = loc }
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let is_expr_once =
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  let dummy_expr_once = expr_once Location.dummy_loc (Clocks.new_var true) in
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  fun expr -> Corelang.is_eq_expr expr dummy_expr_once
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let unfold_arrow expr =
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 match expr.expr_desc with
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 | Expr_arrow (e1, e2) ->
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    let loc = expr.expr_loc in
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    let ck = expr.expr_clock in
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    { expr with expr_desc = Expr_ite (expr_once loc ck, e1, e2) }
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 | _                   -> assert false
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let unfold_arrow_active = ref true 
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let cpt_fresh = ref 0
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(* Generate a new local [node] variable *)
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let mk_fresh_var node loc ty ck =
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  let vars = get_node_vars node in
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  let rec aux () =
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  incr cpt_fresh;
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  let s = Printf.sprintf "__%s_%d" node.node_id !cpt_fresh in
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  if List.exists (fun v -> v.var_id = s) vars then aux () else
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  {
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    var_id = s;
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    var_dec_type = dummy_type_dec;
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    var_dec_clock = dummy_clock_dec;
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    var_dec_const = false;
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    var_type = ty;
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    var_clock = ck;
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    var_loc = loc
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  }
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  in aux ()
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(* Generate a new ident expression from a declared variable *)
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let mk_ident_expr v =
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  { expr_tag = new_tag ();
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    expr_desc = Expr_ident v.var_id;
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    expr_type = v.var_type;
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    expr_clock = v.var_clock;
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    expr_delay = Delay.new_var ();
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    expr_annot = None;
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    expr_loc = v.var_loc }
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(* Get the equation in [defs] with [expr] as rhs, if any *)
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let get_expr_alias defs expr =
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 try Some (List.find (fun eq -> is_eq_expr eq.eq_rhs expr) defs)
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 with
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   Not_found -> None
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(* Replace [expr] with (tuple of) [locals] *)
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let replace_expr locals expr =
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 match locals with
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 | []  -> assert false
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 | [v] -> { expr with
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   expr_tag = Utils.new_tag ();
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   expr_desc = Expr_ident v.var_id }
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 | _   -> { expr with
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   expr_tag = Utils.new_tag ();
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   expr_desc = Expr_tuple (List.map mk_ident_expr locals) }
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let unfold_offsets e offsets =
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  let add_offset e d =
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(*Format.eprintf "add_offset %a %a@." Dimension.pp_dimension (Types.array_type_dimension e.expr_type) Dimension.pp_dimension d;*)
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    { e with
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      expr_tag = Utils.new_tag ();
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      expr_loc = d.Dimension.dim_loc;
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      expr_type = Types.array_element_type e.expr_type;
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      expr_desc = Expr_access (e, d) } in
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 List.fold_left add_offset e offsets
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(* Create an alias for [expr], if none exists yet *)
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let mk_expr_alias node (defs, vars) expr =
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  match get_expr_alias defs expr with
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  | Some eq ->
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    let aliases = List.map (fun id -> List.find (fun v -> v.var_id = id) vars) eq.eq_lhs in
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    (defs, vars), replace_expr aliases expr
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  | None    ->
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    let new_aliases =
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      List.map2
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	(mk_fresh_var node expr.expr_loc)
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	(Types.type_list_of_type expr.expr_type)
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	(Clocks.clock_list_of_clock expr.expr_clock) in
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    let new_def =
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      mkeq expr.expr_loc (List.map (fun v -> v.var_id) new_aliases, expr)
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    in (new_def::defs, new_aliases@vars), replace_expr new_aliases expr
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(* Create an alias for [expr], if [expr] is not already an alias (i.e. an ident)
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   and [opt] is true *)
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let mk_expr_alias_opt opt node defvars expr =
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  match expr.expr_desc with
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  | Expr_ident alias ->
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    defvars, expr
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  | _                -> 
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    if opt
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    then
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      mk_expr_alias node defvars expr
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    else
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      defvars, expr
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(* Create a (normalized) expression from [ref_e], 
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   replacing description with [norm_d],
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   taking propagated [offsets] into account 
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   in order to change expression type *)
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let mk_norm_expr offsets ref_e norm_d =
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  let drop_array_type ty =
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    Types.map_tuple_type Types.array_element_type ty in
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  { ref_e with
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    expr_desc = norm_d;
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    expr_type = Utils.repeat (List.length offsets) drop_array_type ref_e.expr_type }
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(* normalize_<foo> : defs * used vars -> <foo> -> (updated defs * updated vars) * normalized <foo> *)
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let rec normalize_list alias node offsets norm_element defvars elist =
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  List.fold_right
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    (fun t (defvars, qlist) ->
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      let defvars, norm_t = norm_element alias node offsets defvars t in
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      (defvars, norm_t :: qlist)
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    ) elist (defvars, [])
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let rec normalize_expr ?(alias=true) node offsets defvars expr =
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(*  Format.eprintf "normalize %B %a [%a]@." alias Printers.pp_expr expr (Utils.fprintf_list ~sep:"," Dimension.pp_dimension) offsets;*)
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  match expr.expr_desc with
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  | Expr_const _ 
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  | Expr_ident _ -> defvars, unfold_offsets expr offsets
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  | Expr_array elist ->
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    let defvars, norm_elist = normalize_list alias node offsets (fun _ -> normalize_array_expr ~alias:true) defvars elist in
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    let norm_expr = mk_norm_expr offsets expr (Expr_array norm_elist) in
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    mk_expr_alias_opt alias node defvars norm_expr
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  | Expr_power (e1, d) when offsets = [] ->
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    let defvars, norm_e1 = normalize_expr node offsets defvars e1 in
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    let norm_expr = mk_norm_expr offsets expr (Expr_power (norm_e1, d)) in
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    mk_expr_alias_opt alias node defvars norm_expr
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  | Expr_power (e1, d) ->
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    normalize_expr ~alias:alias node (List.tl offsets) defvars e1
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  | Expr_access (e1, d) ->
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    normalize_expr ~alias:alias node (d::offsets) defvars e1
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  | Expr_tuple elist -> 
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    let defvars, norm_elist =
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      normalize_list alias node offsets (fun alias -> normalize_expr ~alias:alias) defvars elist in
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    defvars, mk_norm_expr offsets expr (Expr_tuple norm_elist)
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  | Expr_appl (id, args, None) when Basic_library.is_internal_fun id && Types.is_array_type expr.expr_type ->
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    let defvars, norm_args = normalize_list alias node offsets (fun _ -> normalize_array_expr ~alias:true) defvars (expr_list_of_expr args) in
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    defvars, mk_norm_expr offsets expr (Expr_appl (id, expr_of_expr_list args.expr_loc norm_args, None))
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  | Expr_appl (id, args, None) when Basic_library.is_internal_fun id ->
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    let defvars, norm_args = normalize_expr ~alias:true node offsets defvars args in
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    defvars, mk_norm_expr offsets expr (Expr_appl (id, norm_args, None))
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  | Expr_appl (id, args, r) ->
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    let defvars, norm_args = normalize_expr node [] defvars args in
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    let norm_expr = mk_norm_expr [] expr (Expr_appl (id, norm_args, r)) in
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    if offsets <> []
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    then
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      let defvars, norm_expr = normalize_expr node [] defvars norm_expr in
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      normalize_expr ~alias:alias node offsets defvars norm_expr
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    else
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      mk_expr_alias_opt (alias && not (Basic_library.is_internal_fun id)) node defvars norm_expr
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  | Expr_arrow (e1,e2) when !unfold_arrow_active && not (is_expr_once expr) -> (* Here we differ from Colaco paper: arrows are pushed to the top *)
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    normalize_expr ~alias:alias node offsets defvars (unfold_arrow expr)
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  | Expr_arrow (e1,e2) ->
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    let defvars, norm_e1 = normalize_expr node offsets defvars e1 in
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    let defvars, norm_e2 = normalize_expr node offsets defvars e2 in
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    let norm_expr = mk_norm_expr offsets expr (Expr_arrow (norm_e1, norm_e2)) in
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    mk_expr_alias_opt alias node defvars norm_expr
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  | Expr_pre e ->
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    let defvars, norm_e = normalize_expr node offsets defvars e in
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    let norm_expr = mk_norm_expr offsets expr (Expr_pre norm_e) in
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    mk_expr_alias_opt alias node defvars norm_expr
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  | Expr_fby (e1, e2) ->
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    let defvars, norm_e1 = normalize_expr node offsets defvars e1 in
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    let defvars, norm_e2 = normalize_expr node offsets defvars e2 in
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    let norm_expr = mk_norm_expr offsets expr (Expr_fby (norm_e1, norm_e2)) in
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    mk_expr_alias_opt alias node defvars norm_expr
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  | Expr_when (e, c, l) ->
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    let defvars, norm_e = normalize_expr node offsets defvars e in
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    defvars, mk_norm_expr offsets expr (Expr_when (norm_e, c, l))
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  | Expr_ite (c, t, e) ->
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    let defvars, norm_c = normalize_guard node defvars c in
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    let defvars, norm_t = normalize_cond_expr  node offsets defvars t in
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    let defvars, norm_e = normalize_cond_expr  node offsets defvars e in
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    let norm_expr = mk_norm_expr offsets expr (Expr_ite (norm_c, norm_t, norm_e)) in
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    mk_expr_alias_opt alias node defvars norm_expr
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  | Expr_merge (c, hl) ->
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    let defvars, norm_hl = normalize_branches node offsets defvars hl in
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    let norm_expr = mk_norm_expr offsets expr (Expr_merge (c, norm_hl)) in
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    mk_expr_alias_opt alias node defvars norm_expr
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(* Creates a conditional with a merge construct, which is more lazy *)
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(*
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let norm_conditional_as_merge alias node norm_expr offsets defvars expr =
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 match expr.expr_desc with
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 | Expr_ite (c, t, e) ->
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   let defvars, norm_t = norm_expr (alias node offsets defvars t in
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 | _ -> assert false
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*)
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and normalize_branches node offsets defvars hl =
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 List.fold_right
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   (fun (t, h) (defvars, norm_q) ->
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     let (defvars, norm_h) = normalize_cond_expr node offsets defvars h in
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     defvars, (t, norm_h) :: norm_q
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   )
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   hl (defvars, [])
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and normalize_array_expr ?(alias=true) node offsets defvars expr =
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(*  Format.eprintf "normalize_array %B %a [%a]@." alias Printers.pp_expr expr (Utils.fprintf_list ~sep:"," Dimension.pp_dimension) offsets;*)
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  match expr.expr_desc with
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  | Expr_power (e1, d) when offsets = [] ->
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    let defvars, norm_e1 = normalize_expr node offsets defvars e1 in
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    defvars, mk_norm_expr offsets expr (Expr_power (norm_e1, d))
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  | Expr_power (e1, d) ->
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    normalize_array_expr ~alias:alias node (List.tl offsets) defvars e1
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  | Expr_access (e1, d) -> normalize_array_expr ~alias:alias node (d::offsets) defvars e1
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  | Expr_array elist when offsets = [] ->
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    let defvars, norm_elist = normalize_list alias node offsets (fun _ -> normalize_array_expr ~alias:true) defvars elist in
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    defvars, mk_norm_expr offsets expr (Expr_array norm_elist)
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  | Expr_appl (id, args, None) when Basic_library.is_internal_fun id ->
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    let defvars, norm_args = normalize_list alias node offsets (fun _ -> normalize_array_expr ~alias:true) defvars (expr_list_of_expr args) in
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    defvars, mk_norm_expr offsets expr (Expr_appl (id, expr_of_expr_list args.expr_loc norm_args, None))
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  |  _ -> normalize_expr ~alias:alias node offsets defvars expr
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and normalize_cond_expr ?(alias=true) node offsets defvars expr =
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  (*Format.eprintf "normalize_cond %B %a [%a]@." alias Printers.pp_expr expr (Utils.fprintf_list ~sep:"," Dimension.pp_dimension) offsets;*)
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  match expr.expr_desc with
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  | Expr_access (e1, d) ->
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    normalize_cond_expr ~alias:alias node (d::offsets) defvars e1
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  | Expr_ite (c, t, e) ->
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    let defvars, norm_c = normalize_guard node defvars c in
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    let defvars, norm_t = normalize_cond_expr node offsets defvars t in
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    let defvars, norm_e = normalize_cond_expr node offsets defvars e in
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    defvars, mk_norm_expr offsets expr (Expr_ite (norm_c, norm_t, norm_e))
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  | Expr_merge (c, hl) ->
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    let defvars, norm_hl = normalize_branches node offsets defvars hl in
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    defvars, mk_norm_expr offsets expr (Expr_merge (c, norm_hl))
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  | _ -> normalize_expr ~alias:alias node offsets defvars expr
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and normalize_guard node defvars expr =
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  let defvars, norm_expr = normalize_expr node [] defvars expr in
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  mk_expr_alias_opt true node defvars norm_expr
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(* outputs cannot be memories as well. If so, introduce new local variable.
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*)
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let decouple_outputs node defvars eq =
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  let rec fold_lhs defvars lhs tys cks =
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   match lhs, tys, cks with
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   | [], [], []          -> defvars, []
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   | v::qv, t::qt, c::qc -> let (defs_q, vars_q), lhs_q = fold_lhs defvars qv qt qc in
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			    if List.exists (fun o -> o.var_id = v) node.node_outputs
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			    then
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			      let newvar = mk_fresh_var node eq.eq_loc t c in
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			      let neweq  = mkeq eq.eq_loc ([v], mk_ident_expr newvar) in
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			      (neweq :: defs_q, newvar :: vars_q), newvar.var_id :: lhs_q
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			    else
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			      (defs_q, vars_q), v::lhs_q
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   | _                   -> assert false in
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  let defvars', lhs' =
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    fold_lhs
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      defvars
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      eq.eq_lhs
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      (Types.type_list_of_type eq.eq_rhs.expr_type)
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      (Clocks.clock_list_of_clock eq.eq_rhs.expr_clock) in
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  defvars', {eq with eq_lhs = lhs' }
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let rec normalize_eq node defvars eq = 
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  match eq.eq_rhs.expr_desc with
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  | Expr_pre _
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  | Expr_fby _  ->
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    let (defvars', eq') = decouple_outputs node defvars eq in
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    let (defs', vars'), norm_rhs = normalize_expr ~alias:false node [] defvars' eq'.eq_rhs in
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    let norm_eq = { eq' with eq_rhs = norm_rhs } in
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    (norm_eq::defs', vars')
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  | Expr_array _ ->
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    let (defs', vars'), norm_rhs = normalize_array_expr ~alias:false node [] defvars eq.eq_rhs in
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    let norm_eq = { eq with eq_rhs = norm_rhs } in
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    (norm_eq::defs', vars')
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  | Expr_appl (id, _, None) when Basic_library.is_internal_fun id && Types.is_array_type eq.eq_rhs.expr_type ->
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    let (defs', vars'), norm_rhs = normalize_array_expr ~alias:false node [] defvars eq.eq_rhs in
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    let norm_eq = { eq with eq_rhs = norm_rhs } in
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    (norm_eq::defs', vars')
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  | Expr_appl _ ->
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    let (defs', vars'), norm_rhs = normalize_expr ~alias:false node [] defvars eq.eq_rhs in
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    let norm_eq = { eq with eq_rhs = norm_rhs } in
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    (norm_eq::defs', vars')
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  | _ ->
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    let (defs', vars'), norm_rhs = normalize_cond_expr ~alias:false node [] defvars eq.eq_rhs in
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    let norm_eq = { eq with eq_rhs = norm_rhs } in
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    norm_eq::defs', vars'
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let normalize_node node = 
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  cpt_fresh := 0;
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  let inputs_outputs = node.node_inputs@node.node_outputs in
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  let is_local v =
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    List.for_all ((!=) v) inputs_outputs in
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  let defs, vars = 
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    List.fold_left (normalize_eq node) ([], inputs_outputs@node.node_locals) node.node_eqs in
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  let new_locals = List.filter is_local vars in
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  let node =
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  { node with node_locals = new_locals; node_eqs = defs }
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  in ((*Printers.pp_node Format.err_formatter node;*) node)
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let normalize_decl decl =
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  match decl.top_decl_desc with
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  | Node nd ->
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    {decl with top_decl_desc = Node (normalize_node nd)}
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  | Open _ | ImportedNode _ | Consts _ -> decl
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let normalize_prog decls = 
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  List.map normalize_decl decls
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(* Local Variables: *)
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(* compile-command:"make -C .." *)
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(* End: *)