CristalCaveGem » LustreC

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(*                                                                  *)

(*  The LustreC compiler toolset   /  The LustreC Development Team  *)

(*  Copyright 2012 -    --   ONERA - CNRS - INPT                    *)

(*                                                                  *)

(*  LustreC is free software, distributed WITHOUT ANY WARRANTY      *)

(*  under the terms of the GNU Lesser General Public License        *)

(*  version 2.1.                                                    *)

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open Lustre_types

open Corelang

(* open LustreSpec *)

(* Consts unfoooolding *)

let is_const i consts = 

  List.exists (fun c -> c.const_id = i) consts

let get_const i consts =

  let c = List.find (fun c -> c.const_id = i) consts in

  c.const_value

let rec expr_unfold_consts consts e = 

{ e with expr_desc = expr_desc_unfold_consts consts e.expr_desc e.expr_type }

and expr_desc_unfold_consts consts e e_type =

  let unfold = expr_unfold_consts consts in

  match e with

  | Expr_const _ -> e

  | Expr_ident i -> if is_const i consts && not (Types.is_array_type e_type) then Expr_const (get_const i consts) else e

  | Expr_array el -> Expr_array (List.map unfold el)

  | Expr_access (e1, d) -> Expr_access (unfold e1, d)

  | Expr_power (e1, d) -> Expr_power (unfold e1, d)

  | Expr_tuple el -> Expr_tuple (List.map unfold el)

  | Expr_ite (c, t, e) -> Expr_ite (unfold c, unfold t, unfold e)

  | Expr_arrow (e1, e2)-> Expr_arrow (unfold e1, unfold e2) 

  | Expr_fby (e1, e2) -> Expr_fby (unfold e1, unfold e2)

  (* | Expr_concat (e1, e2) -> Expr_concat (unfold e1, unfold e2) *)

  (* | Expr_tail e' -> Expr_tail (unfold e') *)

  | Expr_pre e' -> Expr_pre (unfold e')

  | Expr_when (e', i, l)-> Expr_when (unfold e', i, l)

  | Expr_merge (i, hl) -> Expr_merge (i, List.map (fun (t, h) -> (t, unfold h)) hl)

  | Expr_appl (i, e', i') -> Expr_appl (i, unfold e', i')  

let eq_unfold_consts consts eq =

  { eq with eq_rhs = expr_unfold_consts consts eq.eq_rhs }

let node_unfold_consts consts node =

  let eqs, automata = get_node_eqs node in

  assert (automata = []);

  { node with node_stmts = List.map (fun eq -> Eq (eq_unfold_consts consts eq)) eqs }

let prog_unfold_consts prog =

  let consts = List.map const_of_top (get_consts prog) in

    List.map (

      fun decl -> match decl.top_decl_desc with 

	| Node nd -> {decl with top_decl_desc = Node (node_unfold_consts consts nd)}

	| _       -> decl

    ) prog 

(* Distribution of when inside sub-expressions, i.e. (a+b) when c --> a when c + b when c 

   May increase clock disjointness of variables, which is useful for code optimization

*)

let apply_stack expr stack =

 List.fold_left (fun expr (v, t) -> mkexpr expr.expr_loc (Expr_when (expr, v, t))) expr stack

let expr_distribute_when expr =

  let rec distrib stack expr =

    match expr.expr_desc with

    | Expr_const _

    | Expr_ident _

    | Expr_arrow _

    | Expr_fby _

    | Expr_pre _

	-> apply_stack expr stack

    | Expr_appl (id, _, _) when not (Stateless.check_node (node_from_name id))

	-> apply_stack expr stack

    | Expr_ite (c, t, e)

        -> let cid = ident_of_expr c in

           mkexpr expr.expr_loc

	     (Expr_merge (cid,

			  [(tag_true , distrib ((cid,tag_true )::stack) t);

			   (tag_false, distrib ((cid,tag_false)::stack) e)]))

    | Expr_array el -> { expr with expr_desc = (Expr_array (List.map (distrib stack) el)) }

    | Expr_access (e1, d) -> { expr with expr_desc = Expr_access (distrib stack e1, d) }

    | Expr_power (e1, d) -> { expr with expr_desc = Expr_power (distrib stack e1, d) }

    | Expr_tuple el -> { expr with expr_desc = Expr_tuple (List.map (distrib stack) el) }

    | Expr_when (e', i, l)-> distrib ((i, l)::stack) e'

    | Expr_merge (i, hl) -> { expr with expr_desc = Expr_merge (i, List.map (fun (t, h) -> (t, distrib stack h)) hl) }

    | Expr_appl (id, e', i') -> { expr with expr_desc = Expr_appl (id, distrib stack e', i')}

  in distrib [] expr

let eq_distribute_when eq =

  { eq with eq_rhs = expr_distribute_when eq.eq_rhs }

let node_distribute_when node =

  let eqs, automata = get_node_eqs node in

  assert (automata = []);

  { node with node_stmts = List.map (fun eq -> Eq (eq_distribute_when eq)) eqs }

let prog_distribute_when prog =

    List.map (

      fun decl -> match decl.top_decl_desc with 

	| Node nd -> {decl with top_decl_desc = Node (node_distribute_when nd)}

	| _       -> decl

    ) prog 

(* Local Variables: *)

(* compile-command:"make -C .." *)

(* End: *)