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lustrec / src / normalization.ml @ 53206908

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(********************************************************************)
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(*                                                                  *)
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(*  The LustreC compiler toolset   /  The LustreC Development Team  *)
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(*  Copyright 2012 -    --   ONERA - CNRS - INPT                    *)
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(*                                                                  *)
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(*  LustreC is free software, distributed WITHOUT ANY WARRANTY      *)
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(*  under the terms of the GNU Lesser General Public License        *)
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(*  version 2.1.                                                    *)
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(*                                                                  *)
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(********************************************************************)
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open Utils
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open LustreSpec
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open Corelang
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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 = List.hd (Clocks.clock_list_of_clock 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_orig = false;
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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_dec_value = None;
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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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(* 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 expr_of_vdecl 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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(*Format.eprintf "mk_expr_alias %a %a %a@." Printers.pp_expr expr Types.print_ty expr.expr_type Clocks.print_ck expr.expr_clock;*)
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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 (defs, vars) expr =
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(*Format.eprintf "mk_expr_alias_opt %B %a %a %a@." opt Printers.pp_expr expr Types.print_ty expr.expr_type Clocks.print_ck expr.expr_clock;*)
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  match expr.expr_desc with
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  | Expr_ident alias ->
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    (defs, vars), expr
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  | _                ->
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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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      if opt
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      then
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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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      else
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	(defs, vars), 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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(*Format.eprintf "mk_norm_expr %a %a @." Printers.pp_expr ref_e Printers.pp_expr { ref_e with expr_desc = 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 [%a]@." alias Printers.pp_expr expr Types.print_ty expr.expr_type (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) 
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      when Basic_library.is_homomorphic_fun id 
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	&& Types.is_array_type expr.expr_type ->
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    let defvars, norm_args =
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      normalize_list
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	alias
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	node
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	offsets
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	(fun _ -> normalize_array_expr ~alias:true)
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	defvars
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	(expr_list_of_expr args)
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    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_expr_internal_fun expr ->
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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 <> []
210
    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_expr_internal_fun expr)) 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_expr_internal_fun expr ->
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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.
298
*)
299
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
304
			    if List.exists (fun o -> o.var_id = v) node.node_outputs
305
			    then
306
			      let newvar = mk_fresh_var node eq.eq_loc t c in
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			      let neweq  = mkeq eq.eq_loc ([v], expr_of_vdecl newvar) in
308
			      (neweq :: defs_q, newvar :: vars_q), newvar.var_id :: lhs_q
309
			    else
310
			      (defs_q, vars_q), v::lhs_q
311
   | _                   -> assert false in
312
  let defvars', lhs' =
313
    fold_lhs
314
      defvars
315
      eq.eq_lhs
316
      (Types.type_list_of_type eq.eq_rhs.expr_type)
317
      (Clocks.clock_list_of_clock eq.eq_rhs.expr_clock) in
318
  defvars', {eq with eq_lhs = lhs' }
319

    
320
let rec normalize_eq node defvars eq =
321
(*Format.eprintf "normalize_eq %a@." Types.print_ty eq.eq_rhs.expr_type;*)
322
  match eq.eq_rhs.expr_desc with
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  | Expr_pre _
324
  | Expr_fby _  ->
325
    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
327
    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_homomorphic_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
340
    (norm_eq::defs', vars')
341
  | _ ->
342
    let (defs', vars'), norm_rhs = normalize_cond_expr ~alias:false node [] defvars eq.eq_rhs in
343
    let norm_eq = { eq with eq_rhs = norm_rhs } in
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    norm_eq::defs', vars'
345

    
346
(** normalize_node node returns a normalized node,
347
    ie.
348
    - updated locals
349
    - new equations
350
    -
351
*)
352
let normalize_node node =
353
  cpt_fresh := 0;
354
  let inputs_outputs = node.node_inputs@node.node_outputs in
355
  let is_local v =
356
    List.for_all ((!=) v) inputs_outputs in
357
  let orig_vars = inputs_outputs@node.node_locals in
358
  let defs, vars =
359
    List.fold_left (normalize_eq node) ([], orig_vars) (get_node_eqs node) in
360
  (* Normalize the asserts *)
361
  let vars, assert_defs, asserts =
362
    List.fold_left (
363
    fun (vars, def_accu, assert_accu) assert_ ->
364
      let assert_expr = assert_.assert_expr in
365
      let (defs, vars'), expr = 
366
	normalize_expr 
367
	  ~alias:false 
368
	  node 
369
	  [] (* empty offset for arrays *)
370
	  ([], vars) (* defvar only contains vars *)
371
	  assert_expr
372
      in
373
      (*Format.eprintf "New assert vars: %a@.@?" (fprintf_list ~sep:", " Printers.pp_var) vars';*)
374
      vars', defs@def_accu, {assert_ with assert_expr = expr}::assert_accu
375
    ) (vars, [], []) node.node_asserts in
376
  let new_locals = List.filter is_local vars in
377
  (*Format.eprintf "New locals: %a@.@?" (fprintf_list ~sep:", " Printers.pp_var) new_locals;*)
378

    
379
  let new_annots =
380
    if !Options.horntraces then
381
      begin
382
	(* Compute traceability info:
383
	   - gather newly bound variables
384
	   - compute the associated expression without aliases
385
	*)
386
	let diff_vars = List.filter (fun v -> not (List.mem v node.node_locals) ) new_locals in
387
	let norm_traceability = {
388
	  annots = List.map (fun v ->
389
	    let eq =
390
	      try
391
		List.find (fun eq -> eq.eq_lhs = [v.var_id]) (defs@assert_defs) 
392
	      with Not_found -> (Format.eprintf "var not found %s@." v.var_id; assert false) in
393
	    let expr = substitute_expr diff_vars (defs@assert_defs) eq.eq_rhs in
394
	    let pair = mkeexpr expr.expr_loc (mkexpr expr.expr_loc (Expr_tuple [expr_of_ident v.var_id expr.expr_loc; expr])) in
395
	    (["traceability"], pair)
396
	  ) diff_vars;
397
	  annot_loc = Location.dummy_loc
398
	}
399
	in
400
	norm_traceability::node.node_annot
401
      end
402
    else
403
      node.node_annot
404
  in
405

    
406
  let node =
407
  { node with
408
    node_locals = new_locals;
409
    node_stmts = List.map (fun eq -> Eq eq) (defs @ assert_defs);
410
    node_asserts = asserts;
411
    node_annot = new_annots;
412
  }
413
  in ((*Printers.pp_node Format.err_formatter node;*) node)
414

    
415
let normalize_decl decl =
416
  match decl.top_decl_desc with
417
  | Node nd ->
418
    let decl' = {decl with top_decl_desc = Node (normalize_node nd)} in
419
    Hashtbl.replace Corelang.node_table nd.node_id decl';
420
    decl'
421
  | Open _ | ImportedNode _ | Const _ | TypeDef _ -> decl
422

    
423
let normalize_prog decls =
424
  List.map normalize_decl decls
425

    
426
(* Local Variables: *)
427
(* compile-command:"make -C .." *)
428
(* End: *)