CristalCaveGem » LustreC

(* Questions:

   - where are used the mconst. They contain initialization of

   constant in nodes. But they do not seem to be used by c_backend *)

(* Machine processing requires knowledge about variables and local

   variables. Local could be memories while other could not.  *)

type machine_env = {

    is_local: string -> bool;

    get_var: string -> var_decl

  }

let build_env locals non_locals =

  let all = VSet.union locals non_locals in

  {

    is_local = (fun id -> VSet.exists (fun v -> v.var_id = id) locals);

    get_var = (fun id -> try

                  VSet.get id all

                with Not_found -> (

                  Format.eprintf "Impossible to find variable %s in set %a@.@?"

                    id

                    VSet.pp all;

                  raise Not_found

                )

              )  

  }

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

(* Basic functions to translate to machine values, instructions *) 

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

let translate_ident env id =

    let var_id = env.get_var id in

      (* id is a tag, getting its type in the list of declared enums *)

let rec control_on_clock env ck inst =

   control_on_clock env ck1

     (mkinstr

	(MBranch (translate_ident env id,

		  [l, [inst]] )))

(* specialize predefined (polymorphic) operators wrt their instances,

   so that the C semantics is preserved *)

let rec translate_expr env expr =

  let translate_expr = translate_expr env in

    | Expr_ident x                     -> (translate_ident env x).value_desc

      (* special treatment depending on the active backend. For

         functional ones, like horn backend, ite are preserved in

         expression. While they are removed for C or Java backends. *)

      if Backends.is_functional () then

	Fun ("ite", [translate_expr g; translate_expr t; translate_expr e])

      else 

	(Format.eprintf "Normalization error for backend %s: %a@."

	   !Options.output

	   Printers.pp_expr expr;

	 raise NormalizationError)

let translate_guard env expr =

  | Expr_ident x  -> translate_ident env x

let rec translate_act env (y, expr) =

  let translate_act = translate_act env in

  let translate_guard = translate_guard env in

  let translate_ident = translate_ident env in

  let translate_expr = translate_expr env in

let reset_instance env i r c =

  | Some r      -> let g = translate_guard env r in

                      env

(* Datastructure updated while visiting equations *)

type machine_ctx = {

    m: VSet.t; (* Memories *)

    si: instr_t list;

    j: (Lustre_types.top_decl * Dimension.dim_expr list) Utils.IMap.t;

    s: instr_t list;

  }

let ctx_init = { m = VSet.empty; (* memories *)

                 si = []; (* init instr *)

                 j = Utils.IMap.empty;

                 s = [] }

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

(* Main function to translate equations into this machine context we

   are building *) 

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

let translate_eq env ctx eq =

  let translate_expr = translate_expr env in

  let translate_act = translate_act env in

  let control_on_clock = control_on_clock env in

  let reset_instance = reset_instance env in

     let var_x = env.get_var x in

     { ctx with

       si = mkinstr (MReset o) :: ctx.si;

       j = Utils.IMap.add o (Arrow.arrow_top_decl, []) ctx.j;

       s = (control_on_clock

              eq.eq_rhs.expr_clock

              (mkinstr ?lustre_eq:(Some eq) (MStep ([var_x], o, [c1;c2])))

           ) :: ctx.s

     }

  | [x], Expr_pre e1 when env.is_local x    ->

     let var_x = env.get_var x in

      { ctx with

        m = VSet.add var_x ctx.m;

        s = control_on_clock

              eq.eq_rhs.expr_clock

              (mkinstr ?lustre_eq:(Some eq)

                 (MStateAssign (var_x, translate_expr e1)))

            :: ctx.s

      }

  | [x], Expr_fby (e1, e2) when env.is_local x ->

     let var_x = env.get_var x in

     { ctx with

       m = VSet.add var_x ctx.m;

       si = mkinstr ?lustre_eq:(Some eq)

              (MStateAssign (var_x, translate_expr e1))

            :: ctx.si;

       s = control_on_clock

             eq.eq_rhs.expr_clock

             (mkinstr ?lustre_eq:(Some eq)

                (MStateAssign (var_x, translate_expr e2)))

           :: ctx.s

     }

     let var_p = List.map (fun v -> env.get_var v) p in

     { ctx with

       si = 

         (if Stateless.check_node node_f then ctx.si else mkinstr (MReset o) :: ctx.si);

      j = Utils.IMap.add o call_f ctx.j;

      s = (if Stateless.check_node node_f

           then []

           else reset_instance o r call_ck) @

	    (control_on_clock call_ck

               (mkinstr ?lustre_eq:(Some eq) (MStep (var_p, o, vl))))

            :: ctx.s

     }

    let var_x = env.get_var x in

    { ctx with

      s = 

     control_on_clock 

       (translate_act (var_x, eq.eq_rhs)) :: ctx.s

    }

       Format.eprintf "internal error: Machine_code.translate_eq %a@?"

         Printers.pp_node_eq eq;

let constant_equations locals =

 VSet.fold (fun vdecl eqs ->

   locals []

let translate_eqs env ctx eqs =

  List.fold_right (fun eq ctx -> translate_eq env ctx eq) eqs ctx;;

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

(* Processing nodes *) 

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

          (i+1,

           assert_var::vars,

           eq::eqlist,

           {expr with expr_desc = Expr_ident var_id}::assertlist)

let translate_core sorted_eqs locals other_vars =

  let constant_eqs = constant_equations locals in

  let env = build_env locals other_vars  in

  (* Compute constants' instructions  *)

  let ctx0 = translate_eqs env ctx_init constant_eqs in

  assert (VSet.is_empty ctx0.m);

  assert (ctx0.si = []);

  assert (Utils.IMap.is_empty ctx0.j);

  (* Compute ctx for all eqs *)

  let ctx = translate_eqs env ctx_init sorted_eqs in

  ctx, ctx0.s

let translate_decl nd sch =

  (* Extracting eqs, variables ..  *)

  let eqs, auts = get_node_eqs nd in

  assert (auts = []); (* Automata should be expanded by now *)

  (* Build the env: variables visible in the current scope *)

  let locals = VSet.of_list locals_list in

  let inout_vars = (VSet.of_list (nd.node_inputs @ nd.node_outputs)) in

  let env = build_env locals inout_vars  in 

  (* Computing main content *)

  let schedule = sch.Scheduling_type.schedule in

  let sorted_eqs = Scheduling.sort_equations_from_schedule eqs schedule in

  let ctx, ctx0_s = translate_core (assert_instrs@sorted_eqs) locals inout_vars in

(* CODE QUI MARCHE

  let constant_eqs = constant_equations locals in

  (* Compute constants' instructions  *)

  let ctx0 = translate_eqs env ctx_init constant_eqs in

  assert (VSet.is_empty ctx0.m);

  assert (ctx0.si = []);

  assert (Utils.IMap.is_empty ctx0.j);

  (* Compute ctx for all eqs *)

  let ctx = translate_eqs env ctx_init (assert_instrs@sorted_eqs) in

 *)

  (*

  (* Processing spec: locals would be actual locals of the spec while

     non locals would be inputs/ouptpus of the node. Locals of the

     node are not visible. *)

  let spec =

    match nd.node_spec with

    | None -> None

    | Some spec -> translate_spec inout_vars spec

        inout_vars spec =

    let locals = VSet.of_list spec.locals in

    let spec_consts = VSet.of_list spec.consts in

    let other_spec_vars = VSet.union inout_vars spec_consts in

    let spec_env = build_env spec_locals other_spec_vars in

   *)             

  let mmap = Utils.IMap.elements ctx.j in

    mmemory = VSet.elements ctx.m;

    minit = ctx.si;

    mconst = ctx0_s;

        step_inputs = nd.node_inputs;

        step_outputs = nd.node_outputs;

        step_locals = (* Removing computed memories from locals *)

          VSet.elements (VSet.diff locals ctx.m);

        step_checks = List.map (fun d -> d.Dimension.dim_loc,

                                         translate_expr env 

                                           (expr_of_dimension d))

                        nd.node_checks;

        step_instrs = (

	  (* special treatment depending on the active backend. For horn backend,

	  if !Backends.join_guards then

	    join_guards_list ctx.s

	  else

	    ctx.s

        );

        step_asserts = List.map (translate_expr env) nd_node_asserts;

      };