CristalCaveGem » LustreC

(********************************************************************)

(*                                                                  *)

(*  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.                                                    *)

(*                                                                  *)

(********************************************************************)

open Utils

open Format

    when some criteria are met. This creation of fresh definition is performed by

    the function mk_expr_alias_opt when the alias argument is on.

    Initial expressions, ie expressions attached a variable in an equation

    definition are not aliased. This non-alias feature is propagated in the

    expression AST for array access and power construct, tuple, and some special

    cases of arrows.

    Two global variables may impact the normalization process:

    - unfold_arrow_active

    - force_alias_ite: when set, bind a fresh alias for then and else

      definitions.

*)

(* Two global variables *)

let unfold_arrow_active = ref true

let force_alias_ite = ref false

{ expr_tag = Utils.new_tag ();

  expr_desc = Expr_const (Const_tag tag_true);

  expr_type = Type_predef.type_bool;

  expr_clock = ck;

  expr_delay = Delay.new_var ();

  expr_annot = None;

  expr_loc = loc }

let expr_false loc ck =

{ expr_tag = Utils.new_tag ();

  expr_desc = Expr_const (Const_tag tag_false);

  expr_type = Type_predef.type_bool;

  expr_clock = ck;

  expr_delay = Delay.new_var ();

  expr_annot = None;

  expr_loc = loc }

let expr_once loc ck =

 { expr_tag = Utils.new_tag ();

  expr_desc = Expr_arrow (expr_true loc ck, expr_false loc ck);

  expr_type = Type_predef.type_bool;

  expr_clock = ck;

  expr_delay = Delay.new_var ();

  expr_annot = None;

  expr_loc = loc }

let is_expr_once =

  let dummy_expr_once = expr_once Location.dummy_loc (Clocks.new_var true) in

  fun expr -> Corelang.is_eq_expr expr dummy_expr_once

let unfold_arrow expr =

 match expr.expr_desc with

 | Expr_arrow (e1, e2) ->

    let loc = expr.expr_loc in

 | _                   -> assert false

(* Generate a new local [node] variable *)

let mk_fresh_var node loc ty ck =

  incr cpt_fresh;

  let s = Printf.sprintf "__%s_%d" node.node_id !cpt_fresh in

  if List.exists (fun v -> v.var_id = s) vars then aux () else

  {

    var_id = s;

    var_dec_clock = dummy_clock_dec;

    var_dec_const = false;

    var_clock = ck;

    var_loc = loc

  }

  in aux ()

(* Get the equation in [defs] with [expr] as rhs, if any *)

let get_expr_alias defs expr =

 try Some (List.find (fun eq -> is_eq_expr eq.eq_rhs expr) defs)

 with

let replace_expr locals expr =

 match locals with

 | []  -> assert false

 | [v] -> { expr with

   expr_tag = Utils.new_tag ();

   expr_desc = Expr_ident v.var_id }

 | _   -> { expr with

   expr_tag = Utils.new_tag ();

let unfold_offsets e offsets =

  let add_offset e d =

    let res = *)

      expr_tag = Utils.new_tag ();

      expr_loc = d.Dimension.dim_loc;

      expr_type = Types.array_element_type e.expr_type;

(*in (Format.eprintf "= %a @." Printers.pp_expr res; res) *)

  in

(* Create an alias for [expr], if none exists yet *)

let mk_expr_alias node (defs, vars) expr =

  | Some eq ->

    let aliases = List.map (fun id -> List.find (fun v -> v.var_id = id) vars) eq.eq_lhs in

    (defs, vars), replace_expr aliases expr

  | None    ->

    let new_aliases =

      List.map2

	(mk_fresh_var node expr.expr_loc)

	(Types.type_list_of_type expr.expr_type)

	(Clocks.clock_list_of_clock expr.expr_clock) in

    let new_def =

      mkeq expr.expr_loc (List.map (fun v -> v.var_id) new_aliases, expr)

   and [opt] is true *)

(*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;*)

  | Expr_ident alias ->

    | Some eq ->

      let aliases = List.map (fun id -> List.find (fun v -> v.var_id = id) vars) eq.eq_lhs in

      (defs, vars), replace_expr aliases expr

    | None    ->

      if opt

      then

	let new_aliases =

	  List.map2

	    (mk_fresh_var node expr.expr_loc)

	    (Types.type_list_of_type expr.expr_type)

	    (Clocks.clock_list_of_clock expr.expr_clock) in

	let new_def =

	  mkeq expr.expr_loc (List.map (fun v -> v.var_id) new_aliases, expr)

	(* Typing and Registering machine type *) 

	(defs, vars), expr

let mk_norm_expr offsets ref_e norm_d =

    Types.map_tuple_type Types.array_element_type ty in

  { ref_e with

    expr_desc = norm_d;

    expr_type = Utils.repeat (List.length offsets) drop_array_type ref_e.expr_type }

let rec normalize_list alias node offsets norm_element defvars elist =

  List.fold_right

    (fun t (defvars, qlist) ->

      let defvars, norm_t = norm_element alias node offsets defvars t in

      (defvars, norm_t :: qlist)

    ) elist (defvars, [])

  | Expr_array elist ->

     let norm_expr = mk_norm_expr offsets expr (Expr_array norm_elist) in

     mk_expr_alias_opt alias node defvars norm_expr

     let norm_expr = mk_norm_expr offsets expr (Expr_power (norm_e1, d)) in

     mk_expr_alias_opt alias node defvars norm_expr

       normalize_list alias node offsets (fun alias -> normalize_expr ~alias:alias ~alias_basic:false) defvars elist in

     defvars, mk_norm_expr offsets expr (Expr_tuple norm_elist)

       normalize_list

	 alias

	 node

	 offsets

	 (fun _ -> normalize_array_expr ~alias:true)

	 defvars

	 (expr_list_of_expr args)

     in

     defvars, mk_norm_expr offsets expr (Expr_appl (id, expr_of_expr_list args.expr_loc norm_args, None))

     let defvars, norm_args = normalize_expr ~alias:true node offsets defvars args in

     defvars, mk_norm_expr offsets expr (Expr_appl (id, norm_args, None))

       match r with

       | None -> defvars, None

       | Some r ->

	  let defvars, norm_r = normalize_expr ~alias_basic:true node [] defvars r in

	  defvars, Some norm_r

     in

     let defvars, norm_args = normalize_expr node [] defvars args in

     let norm_expr = mk_norm_expr [] expr (Expr_appl (id, norm_args, r)) in

     if offsets <> []

     then

       let defvars, norm_expr = normalize_expr node [] defvars norm_expr in

       normalize_expr ~alias:alias node offsets defvars norm_expr

     else

       mk_expr_alias_opt (alias && (!force_alias_internal_fun || alias_basic

				    || not (Basic_library.is_expr_internal_fun expr)))

	 node defvars norm_expr

     normalize_expr ~alias:alias node offsets defvars (unfold_arrow expr)

     let defvars, norm_e2 = normalize_expr node offsets defvars e2 in

     let norm_expr = mk_norm_expr offsets expr (Expr_arrow (norm_e1, norm_e2)) in

     mk_expr_alias_opt alias node defvars norm_expr

     let norm_expr = mk_norm_expr offsets expr (Expr_pre norm_e) in

     mk_expr_alias_opt alias node defvars norm_expr

     let defvars, norm_e2 = normalize_expr node offsets defvars e2 in

     let norm_expr = mk_norm_expr offsets expr (Expr_fby (norm_e1, norm_e2)) in

     mk_expr_alias_opt alias node defvars norm_expr

     defvars, mk_norm_expr offsets expr (Expr_when (norm_e, c, l))

     let defvars, norm_t = normalize_cond_expr  node offsets defvars t in

     let defvars, norm_e = normalize_cond_expr  node offsets defvars e in

     let norm_expr = mk_norm_expr offsets expr (Expr_ite (norm_c, norm_t, norm_e)) in

     mk_expr_alias_opt alias node defvars norm_expr

     let norm_expr = mk_norm_expr offsets expr (Expr_merge (c, norm_hl)) in

     mk_expr_alias_opt alias node defvars norm_expr

(*

  match expr.expr_desc with

  | Expr_ite (c, t, e) ->

  let defvars, norm_t = norm_expr (alias node offsets defvars t in

  | _ -> assert false

    (fun (t, h) (defvars, norm_q) ->

      let (defvars, norm_h) = normalize_cond_expr node offsets defvars h in

      defvars, (t, norm_h) :: norm_q

    )

    hl (defvars, [])

and normalize_array_expr ?(alias=true) node offsets defvars expr =

  | Expr_power (e1, d) when offsets = [] ->

     defvars, mk_norm_expr offsets expr (Expr_power (norm_e1, d))

  | Expr_array elist when offsets = [] ->

     defvars, mk_norm_expr offsets expr (Expr_array norm_elist)

     defvars, mk_norm_expr offsets expr (Expr_appl (id, expr_of_expr_list args.expr_loc norm_args, None))

and normalize_cond_expr ?(alias=true) node offsets defvars expr =

  (*Format.eprintf "normalize_cond %B %a [%a]@." alias Printers.pp_expr expr (Utils.fprintf_list ~sep:"," Dimension.pp_dimension) offsets;*)

  match expr.expr_desc with

  | Expr_access (e1, d) ->

     let defvars, norm_t = normalize_cond_expr node offsets defvars t in

     let defvars, norm_e = normalize_cond_expr node offsets defvars e in

     defvars, mk_norm_expr offsets expr (Expr_ite (norm_c, norm_t, norm_e))

     defvars, mk_norm_expr offsets expr (Expr_merge (c, norm_hl))

     (* Forcing alias creation for then/else expressions *)

     let defvars, norm_expr =

       normalize_expr ~alias:alias node offsets defvars expr

     in

     mk_expr_alias_opt true node defvars norm_expr

  | _ -> (* default case without the force_alias_ite option *)

     normalize_expr ~alias:alias node offsets defvars expr

(* outputs cannot be memories as well. If so, introduce new local variable.

*)

let decouple_outputs node defvars eq =

  let rec fold_lhs defvars lhs tys cks =

   match lhs, tys, cks with

   | [], [], []          -> defvars, []

   | v::qv, t::qt, c::qc -> let (defs_q, vars_q), lhs_q = fold_lhs defvars qv qt qc in

			    if List.exists (fun o -> o.var_id = v) node.node_outputs

			    then

			      let newvar = mk_fresh_var node eq.eq_loc t c in

			    else

			      (defs_q, vars_q), v::lhs_q

   | _                   -> assert false in

  let defvars', lhs' =

    fold_lhs

      defvars

      eq.eq_lhs

      (Types.type_list_of_type eq.eq_rhs.expr_type)

      (Clocks.clock_list_of_clock eq.eq_rhs.expr_clock) in

  defvars', {eq with eq_lhs = lhs' }

  | Expr_pre _

  | Expr_fby _  ->

    let (defvars', eq') = decouple_outputs node defvars eq in

    let (defs', vars'), norm_rhs = normalize_expr ~alias:false node [] defvars' eq'.eq_rhs in

    let norm_eq = { eq' with eq_rhs = norm_rhs } in

    (norm_eq::defs', vars')

  | Expr_array _ ->

    let (defs', vars'), norm_rhs = normalize_array_expr ~alias:false node [] defvars eq.eq_rhs in

    let norm_eq = { eq with eq_rhs = norm_rhs } in

    (norm_eq::defs', vars')

    let norm_eq = { eq with eq_rhs = norm_rhs } in

    (norm_eq::defs', vars')

  | Expr_appl _ ->

    let (defs', vars'), norm_rhs = normalize_expr ~alias:false node [] defvars eq.eq_rhs in

    let norm_eq = { eq with eq_rhs = norm_rhs } in

    (norm_eq::defs', vars')

  | _ ->

    let (defs', vars'), norm_rhs = normalize_cond_expr ~alias:false node [] defvars eq.eq_rhs in

    let norm_eq = { eq with eq_rhs = norm_rhs } in

    norm_eq::defs', vars'

    ie.

    - new equations

  let inputs_outputs = node.node_inputs@node.node_outputs in

    List.for_all ((!=) v) orig_vars in

    if auts != [] then assert false; (* Automata should be expanded by now. *)

    List.fold_left (normalize_eq node) ([], orig_vars) eqs in

	let assert_expr = assert_.assert_expr in

	let (defs, vars'), expr = 

	  normalize_expr 

	    ~alias:true (* forcing introduction of new equations for fcn calls *) 

	    node 

	    [] (* empty offset for arrays *)

	    ([], vars) (* defvar only contains vars *)

	    assert_expr

	in

							  vars and initial locals ones *)

  let all_locals = node.node_locals @ new_locals in (* we add again, at the

						       local declared ones *)

  (* Updating annotations: traceability and machine types for fresh variables *)

  (* Compute traceability info:

     - gather newly bound variables

     - compute the associated expression without aliases

  *)

    if !Options.traces then

      begin

	  annots = List.map (fun v ->

	    let eq =

	      try

	      with Not_found -> 

		(

		  Format.eprintf "Traceability annotation generation: var %s not found@." v.var_id; 

		  assert false

		) 

	    in

	  ) diff_vars;

	  annot_loc = Location.dummy_loc

	norm_traceability::node.node_annot

      end

    else

      node.node_annot

    List.fold_left (fun annots v ->

  	let typ_name = Machine_types.type_name typ in

	let loc = v.var_loc in

	let typ_as_string =

	  mkexpr

	    loc

	    (Expr_const

	       (Const_string typ_name))

	in

	let pair = expr_to_eexpr (expr_of_expr_list loc [expr_of_vdecl v; typ_as_string]) in

	Annotations.add_expr_ann node.node_id pair.eexpr_tag Machine_types.keyword;

	{annots = [Machine_types.keyword, pair]; annot_loc = loc}::annots

      else

	annots

    ) new_annots new_locals

  in

      node_asserts = asserts;

      node_annot = new_annots;

    }

let normalize_decl decl =

  match decl.top_decl_desc with

  | Node nd ->

    Hashtbl.replace Corelang.node_table nd.node_id decl';

    decl'

  let old_unfold_arrow_active = !unfold_arrow_active in

  let old_force_alias_ite = !force_alias_ite in

  (* Backend specific configurations for normalization *)

  let _ =

    match backend with

    | "lustre" ->

    (* Special treatment of arrows in lustre backend. We want to keep them *)

       unfold_arrow_active := false;

       (* Forcing ite normalization *)

      force_alias_ite := true;

      force_alias_internal_fun := true;

    )

  in

  let res = List.map normalize_decl decls in

  (* Restoring previous settings *)

  unfold_arrow_active := old_unfold_arrow_active;

  force_alias_ite := old_force_alias_ite;

  (* Local Variables: *)

(* End: *)