CristalCaveGem » LustreC

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(*                                                                  *)

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

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

(*                                                                  *)

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

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

(*  version 2.1.                                                    *)

(*                                                                  *) 

(*  This file was originally from the Prelude compiler              *)

(*                                                                  *) 

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(** Clocks definitions and a few utility functions on clocks. *)

open Utils

open Format

(* (\* Clock type sets, for subtyping. *\) *)

(* type clock_set = *)

(*     CSet_all *)

(*   | CSet_pck of int*rat *)

(* Clock carriers basically correspond to the "c" in "x when c" *)

type carrier_desc =

  | Carry_const of ident

  | Carry_name

  | Carry_var

  | Carry_link of carrier_expr

(* Carriers are scoped, to detect clock extrusion. In other words, we

   check the scope of a clock carrier before generalizing it. *)

and carrier_expr =

    {mutable carrier_desc: carrier_desc;

     mutable carrier_scoped: bool;

     carrier_id: int}

type clock_expr =

    {mutable cdesc: clock_desc;

     mutable cscoped: bool;

     cid: int}

(* pck stands for periodic clock. Easier not to separate pck from other clocks *)

and clock_desc =

  | Carrow of clock_expr * clock_expr

  | Ctuple of clock_expr list

  | Con of clock_expr * carrier_expr * ident

  (* | Pck_up of clock_expr * int *)

  (* | Pck_down of clock_expr * int *)

  (* | Pck_phase of clock_expr * rat *)

  (* | Pck_const of int * rat *)

  | Cvar (* of clock_set *) (* Monomorphic clock variable *)

  | Cunivar (* of clock_set *) (* Polymorphic clock variable *)

  | Clink of clock_expr (* During unification, make links instead of substitutions *)

  | Ccarrying of carrier_expr * clock_expr

type error =

  | Clock_clash of clock_expr * clock_expr

  (* | Not_pck *)

  (* | Clock_set_mismatch of clock_expr * clock_set *)

  | Cannot_be_polymorphic of clock_expr

  | Invalid_imported_clock of clock_expr

  | Invalid_const of clock_expr

  | Factor_zero

  | Carrier_mismatch of carrier_expr * carrier_expr

  | Carrier_extrusion of clock_expr * carrier_expr

  | Clock_extrusion of clock_expr * clock_expr

exception Unify of clock_expr * clock_expr

exception Mismatch of carrier_expr * carrier_expr

exception Scope_carrier of carrier_expr

exception Scope_clock of clock_expr

exception Error of Location.t * error

let rec print_carrier fmt cr =

 (* (if cr.carrier_scoped then fprintf fmt "[%t]" else fprintf fmt "%t") (fun fmt -> *)

  match cr.carrier_desc with

  | Carry_const id -> fprintf fmt "%s" id

  | Carry_name ->

      fprintf fmt "_%s" (name_of_carrier cr.carrier_id)

  | Carry_var ->

    fprintf fmt "'%s" (name_of_carrier cr.carrier_id)

  | Carry_link cr' ->

    print_carrier fmt cr'

(* Simple pretty-printing, performs no simplifications. Linear

   complexity. For debug mainly. *)

let rec print_ck_long fmt ck =

  match ck.cdesc with

  | Carrow (ck1,ck2) ->

      fprintf fmt "%a -> %a" print_ck_long ck1 print_ck_long ck2

  | Ctuple cklist ->

    fprintf fmt "(%a)"

      (fprintf_list ~sep:" * " print_ck_long) cklist

  | Con (ck,c,l) ->

    fprintf fmt "%a on %s(%a)" print_ck_long ck l print_carrier c

  | Cvar -> fprintf fmt "'_%i" ck.cid 

  | Cunivar -> fprintf fmt "'%i" ck.cid 

  | Clink ck' ->

    fprintf fmt "link %a" print_ck_long ck'

  | Ccarrying (cr,ck') ->

    fprintf fmt "(%a:%a)" print_carrier cr print_ck_long ck'

let new_id = ref (-1)

let rec bottom =

  { cdesc = Clink bottom; cid = -666; cscoped = false }

let new_ck desc scoped =

  incr new_id; {cdesc=desc; cid = !new_id; cscoped = scoped}

let new_var scoped = new_ck Cvar scoped

let new_univar () = new_ck Cunivar false

let new_carrier_id = ref (-1)

let new_carrier desc scoped =

  incr new_carrier_id; {carrier_desc = desc;

                        carrier_id = !new_carrier_id;

                        carrier_scoped = scoped}

let new_carrier_name () =

  new_carrier Carry_name true

let rec repr =

  function

      {cdesc=Clink ck'} ->

        repr ck'

    | ck -> ck

let rec carrier_repr =

  function {carrier_desc = Carry_link cr'} -> carrier_repr cr'

    | cr -> cr

(** Splits [ck] into the [lhs,rhs] of an arrow clock. Expects an arrow clock

    (ensured by language syntax) *)

let split_arrow ck =

  match (repr ck).cdesc with

  | Carrow (cin,cout) -> cin,cout

    (* Functions are not first order, I don't think the var case

       needs to be considered here *)

  | _ -> failwith "Internal error: not an arrow clock"

let get_carrier_name ck =

 match (repr ck).cdesc with

 | Ccarrying (cr, _) -> Some cr

 | _                 -> None

let rename_carrier_static rename cr =

  match (carrier_repr cr).carrier_desc with

  | Carry_const id -> { cr with carrier_desc = Carry_const (rename id) }

  | _              -> (Format.eprintf "internal error: Clocks.rename_carrier_static %a@." print_carrier cr; assert false)

let rec rename_static rename ck =

 match (repr ck).cdesc with

 | Ccarrying (cr, ck') -> { ck with cdesc = Ccarrying (rename_carrier_static rename cr, rename_static rename ck') }

 | Con (ck', cr, l)    -> { ck with cdesc = Con (rename_static rename ck', rename_carrier_static rename cr, l) }

 | _                   -> ck

let uncarrier ck =

 match ck.cdesc with

 | Ccarrying (_, ck') -> ck'

 | _                  -> ck

(* Removes all links in a clock. Only used for clocks

   simplification though. *)

let rec simplify ck =

  match ck.cdesc with

  | Carrow (ck1,ck2) ->

      new_ck (Carrow (simplify ck1, simplify ck2)) ck.cscoped

  | Ctuple cl ->

      new_ck (Ctuple (List.map simplify cl)) ck.cscoped

  | Con (ck', c, l) ->

      new_ck (Con (simplify ck', c, l)) ck.cscoped

  | Cvar | Cunivar -> ck

  | Clink ck' -> simplify ck'

  | Ccarrying (cr,ck') -> new_ck (Ccarrying (cr, simplify ck')) ck.cscoped

(** Splits ck into the [lhs,rhs] of an arrow clock. Expects an arrow clock

    (ensured by language syntax) *)

let split_arrow ck =

  match (repr ck).cdesc with

  | Carrow (cin,cout) -> cin,cout

  | _ -> failwith "Internal error: not an arrow clock"

(** Returns the clock corresponding to a clock list. *)

let clock_of_clock_list ckl =

  if (List.length ckl) > 1 then

    new_ck (Ctuple ckl) true

  else

    List.hd ckl

let clock_list_of_clock ck =

 match (repr ck).cdesc with

 | Ctuple cl -> cl

 | _         -> [ck]

let clock_on ck cr l =

 clock_of_clock_list (List.map (fun ck -> new_ck (Con (ck,cr,l)) true) (clock_list_of_clock ck))

let clock_current ck =

 clock_of_clock_list (List.map (fun ck -> match (repr ck).cdesc with Con(ck',_,_) -> ck' | _ -> assert false) (clock_list_of_clock ck))

let clock_of_impnode_clock ck =

  let ck = repr ck in

  match ck.cdesc with

  | Carrow _ | Clink _ | Cvar | Cunivar ->

      failwith "internal error clock_of_impnode_clock"

  | Ctuple cklist -> List.hd cklist

  | Con (_,_,_) 

  | Ccarrying (_,_) -> ck

(** [is_polymorphic ck] returns true if [ck] is polymorphic. *)

let rec is_polymorphic ck =

  match ck.cdesc with

  | Cvar -> false

  | Carrow (ck1,ck2) -> (is_polymorphic ck1) || (is_polymorphic ck2)

  | Ctuple ckl -> List.exists (fun c -> is_polymorphic c) ckl

  | Con (ck',_,_) -> is_polymorphic ck'

  | Cunivar  -> true

  | Clink ck' -> is_polymorphic ck'

  | Ccarrying (_,ck') -> is_polymorphic ck'

(** [constrained_vars_of_clock ck] returns the clock variables subject

    to sub-typing constraints appearing in clock [ck]. Removes duplicates *)

(* Used mainly for debug, non-linear complexity. *)

let rec constrained_vars_of_clock ck =

  let rec aux vars ck =

    match ck.cdesc with

    | Cvar -> vars

    | Carrow (ck1,ck2) ->

        let l = aux vars ck1 in

        aux l ck2

    | Ctuple ckl ->

        List.fold_left

          (fun acc ck' -> aux acc ck') 

          vars ckl

    | Con (ck',_,_) -> aux vars ck'

    | Cunivar -> vars

    | Clink ck' -> aux vars ck'

    | Ccarrying (_,ck') -> aux vars ck'

  in

  aux [] ck

let eq_carrier cr1 cr2 =

  match (carrier_repr cr1).carrier_desc, (carrier_repr cr2).carrier_desc with

 | Carry_const id1, Carry_const id2 -> id1 = id2

 | _                                -> cr1.carrier_id = cr2.carrier_id

let eq_clock ck1 ck2 =

 (repr ck1).cid = (repr ck2).cid

(* Returns the clock root of a clock *)

let rec root ck =

  let ck = repr ck in

  match ck.cdesc with

  | Ctuple (ck'::_)

  | Con (ck',_,_) | Clink ck' | Ccarrying (_,ck') -> root ck'

  | Cvar | Cunivar -> ck

  | Carrow _ | Ctuple _ -> failwith "Internal error root"

(* Returns the branch of clock [ck] in its clock tree *)

let rec branch ck =

  let rec branch ck acc =

    match (repr ck).cdesc with

    | Ccarrying (_, ck) -> branch ck acc

    | Con (ck, cr, l)   -> branch ck ((cr, l) :: acc)

    | Ctuple (ck::_)    -> branch ck acc

    | Ctuple _

    | Carrow _          -> assert false

    | _                 -> acc

  in branch ck [];;

let clock_of_root_branch r br =

 List.fold_left (fun ck (cr,l) -> new_ck (Con (ck, cr, l)) true) r br

(* Computes the (longest) common prefix of two branches *)

let rec common_prefix br1 br2 =

 match br1, br2 with

 | []          , _

 | _           , []           -> []

 | (cr1,l1)::q1, (cr2,l2)::q2 ->

   if eq_carrier cr1 cr2 && (l1 = l2)

   then (cr1, l1) :: common_prefix q1 q2

   else []

(* Tests whether clock branches [br1] nd [br2] are statically disjoint *)

let rec disjoint_branches br1 br2 =

 match br1, br2 with

 | []          , _

 | _           , []           -> false

 | (cr1,l1)::q1, (cr2,l2)::q2 -> eq_carrier cr1 cr2 && ((l1 <> l2) || disjoint_branches q1 q2);;

(* Disjunction relation between variables based upon their static clocks. *)

let disjoint ck1 ck2 =

  eq_clock (root ck1) (root ck2) && disjoint_branches (branch ck1) (branch ck2)

let print_cvar fmt cvar =

  match cvar.cdesc with

  | Cvar ->

 (*

      if cvar.cscoped

      then

	fprintf fmt "[_%s]"

	  (name_of_type cvar.cid)

      else

 *)

	fprintf fmt "_%s"

	  (name_of_type cvar.cid)

  | Cunivar ->

 (*

      if cvar.cscoped

      then

	fprintf fmt "['%s]"

	  (name_of_type cvar.cid)

      else

 *)

	fprintf fmt "'%s"

	  (name_of_type cvar.cid)

  | _ -> failwith "Internal error print_cvar"

(* Nice pretty-printing. Simplifies expressions before printing them. Non-linear

   complexity. *)

let print_ck fmt ck =

  let rec aux fmt ck =

    match ck.cdesc with

    | Carrow (ck1,ck2) ->

      fprintf fmt "%a -> %a" aux ck1 aux ck2

    | Ctuple cklist ->

      fprintf fmt "(%a)" 

	(fprintf_list ~sep:" * " aux) cklist

    | Con (ck,c,l) ->

      fprintf fmt "%a on %s(%a)" aux ck l print_carrier c

    | Cvar ->

(*

      if ck.cscoped

      then

        fprintf fmt "[_%s]" (name_of_type ck.cid)

      else

*)

	fprintf fmt "_%s" (name_of_type ck.cid)

    | Cunivar ->

(*

      if ck.cscoped

      then

        fprintf fmt "['%s]" (name_of_type ck.cid)

      else

*)

        fprintf fmt "'%s" (name_of_type ck.cid)

    | Clink ck' ->

        aux fmt ck'

    | Ccarrying (cr,ck') ->

      fprintf fmt "(%a:%a)" print_carrier cr aux ck'

  in

  let cvars = constrained_vars_of_clock ck in

  aux fmt ck;

  if cvars <> [] then

    fprintf fmt " (where %a)"

      (fprintf_list ~sep:", " print_cvar) cvars

(* prints only the Con components of a clock, useful for printing nodes *)

let rec print_ck_suffix fmt ck =

  match ck.cdesc with

  | Carrow _

  | Ctuple _

  | Cvar 

  | Cunivar    -> ()

  | Con (ck,c,l) ->

    fprintf fmt "%a when %s(%a)" print_ck_suffix ck l print_carrier c

  | Clink ck' ->

    print_ck_suffix fmt ck'

  | Ccarrying (cr,ck') ->

    fprintf fmt "%a" print_ck_suffix ck'

let pp_error fmt = function

  | Clock_clash (ck1,ck2) ->

      reset_names ();

      fprintf fmt "Expected clock %a, got clock %a@."

      print_ck ck1

      print_ck ck2

  | Carrier_mismatch (cr1, cr2) ->

     fprintf fmt "Name clash. Expected clock %a, got clock %a@."

       print_carrier cr1

       print_carrier cr2

  | Cannot_be_polymorphic ck ->

      reset_names ();

    fprintf fmt "The main node cannot have a polymorphic clock: %a@."

      print_ck ck

  | Invalid_imported_clock ck ->

      reset_names ();

    fprintf fmt "Not a valid imported node clock: %a@."

      print_ck ck

  | Invalid_const ck ->

      reset_names ();

    fprintf fmt "Clock %a is not a valid periodic clock@."

      print_ck ck;

  | Factor_zero ->

    fprintf fmt "Cannot apply clock transformation with factor 0@."

  | Carrier_extrusion (ck,cr) ->

    fprintf fmt "This node has clock@.%a@.It is invalid as %a escapes its scope@."

      print_ck ck

      print_carrier cr

  | Clock_extrusion (ck_node,ck) ->

    fprintf fmt "This node has clock@.%a@.It is invalid as %a escapes its scope@."

      print_ck ck_node

      print_ck ck

let const_of_carrier cr =

  match (carrier_repr cr).carrier_desc with

  | Carry_const id -> id

  | Carry_name

  | Carry_var

  | Carry_link _ -> (Format.eprintf "internal error: const_of_carrier %a@." print_carrier cr; assert false) (* TODO check this Xavier *)

let uneval const cr =

  (*Format.printf "Clocks.uneval %s %a@." const print_carrier cr;*)

  let cr = carrier_repr cr in

  match cr.carrier_desc with

  | Carry_var -> cr.carrier_desc <- Carry_const const

  | Carry_name -> cr.carrier_desc <- Carry_const const

  | _         -> assert false

(* Local Variables: *)

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

(* End: *)