2023-01-09 23:04:36 +01:00

1252 lines
48 KiB
OCaml

(** This file contains simplification passes for our Lustre-like AST *)
open Ast
open Passes_utils
open Utils
(** [pass_when_lin] linearises the when construct so that it only appears as
* main construction of right members of equations. *)
let pass_when_lin verbose debug =
(* prefix of the fresh variables to use and counter to make them unique. *)
let varname_prefix = "_whenlin" in
let count = ref 0 in
(** Auxiliary function that linearises an expression. *)
let rec aux_expr vars expr toplevel conds =
match expr with
| EVar _ | EConst _ -> [], vars, expr
| EMonOp (t, op, e) ->
let eqs, vars, e = aux_expr vars e false conds in
eqs, vars, EMonOp (t, op, e)
| EBinOp (t, op, e, e') ->
let eqs, vars, e = aux_expr vars e false conds in
let eqs', vars, e' = aux_expr vars e' false conds in
eqs'@eqs, vars, EBinOp (t, op, e, e')
| EComp (t, op, e, e') ->
let eqs, vars, e = aux_expr vars e false conds in
let eqs', vars, e' = aux_expr vars e' false conds in
eqs'@eqs, vars, EComp (t, op, e, e')
| EReset (t, e, e') ->
let eqs, vars, e = aux_expr vars e false conds in
let eqs', vars, e' = aux_expr vars e' false conds in
eqs'@eqs, vars, EReset (t, e, e')
| ETuple (t, l) ->
let eqs, vars, l = List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = aux_expr vars e false conds in
eqs' @ eqs, vars, (e :: l))
l ([], vars, []) in
eqs, vars, ETuple (t, l)
| EApp (t, n, e) ->
let eqs, vars, e = aux_expr vars e false conds in
eqs, vars, EApp (t, n, e)
| ETriOp (t, op, e, e', e'') ->
let eqs, vars, e = aux_expr vars e false conds in
let eqs', vars, e' = aux_expr vars e' false conds in
let eqs'', vars, e'' = aux_expr vars e'' false conds in
eqs''@eqs'@eqs, vars, ETriOp (t, op, e, e', e'')
| EWhen (t, e, e') ->
let eqs, vars, e = aux_expr vars e false conds in
let eqs', vars, e' = aux_expr vars e' false (e :: conds) in
let e =
List.fold_left
(fun e e' -> EBinOp ([TBool], BOp_and, e,e'))
e conds
in
if toplevel
then
eqs'@eqs, vars, EWhen (t, e, e')
else
begin
if List.length t = 1
then
begin
let newvar = Format.sprintf "%s%d" varname_prefix !count in
let newvar =
match List.hd t with
| TInt -> IVar newvar
| TBool -> BVar newvar
| TReal -> RVar newvar
in
let () = incr count in
let vars = (t @ (fst vars), newvar :: (snd vars)) in
((t, [newvar]), EWhen (t, e, e')) :: eqs'@eqs, vars, EVar (t, newvar)
end
else
raise (PassExn "When should only happened on unary expressions.")
end
in
(** For each node: *)
let aux_when_lin node =
(** Loop on equations to get additional equations and variables. *)
let eqs, vars =
List.fold_left
(fun (eqs, vars) (patt, expr) ->
let eqs', vars, expr = aux_expr vars expr true [] in
(patt, expr) :: eqs' @ eqs, vars)
([], node.n_local_vars) node.n_equations
in
Some { node with n_local_vars = vars; n_equations = eqs }
in
node_pass aux_when_lin
(** [pass_merge_lin] linearises ther merges so that they only appear as main
* construct of right sides of equations.
* This simplifies their handling in next passes and in the C printer. *)
let pass_merge_lin verbose debug =
(* prefix of the fresh variables to use and counter to make them unique. *)
let varname_prefix = "_mergelin" in
let count = ref 0 in
(** Auxiliary function that linearises an expression. *)
let rec aux_expr vars expr toplevel =
match expr with
| EVar _ | EConst _ -> [], vars, expr
| EMonOp (t, op, e) ->
let eqs, vars, e = aux_expr vars e false in
eqs, vars, EMonOp (t, op, e)
| EBinOp (t, op, e, e') ->
let eqs, vars, e = aux_expr vars e false in
let eqs', vars, e' = aux_expr vars e' false in
eqs'@eqs, vars, EBinOp (t, op, e, e')
| EComp (t, op, e, e') ->
let eqs, vars, e = aux_expr vars e false in
let eqs', vars, e' = aux_expr vars e' false in
eqs'@eqs, vars, EComp (t, op, e, e')
| EReset (t, e, e') ->
let eqs, vars, e = aux_expr vars e false in
let eqs', vars, e' = aux_expr vars e' false in
eqs'@eqs, vars, EReset (t, e, e')
| ETuple (t, l) ->
let eqs, vars, l = List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = aux_expr vars e false in
eqs' @ eqs, vars, (e :: l))
l ([], vars, []) in
eqs, vars, ETuple (t, l)
| EApp (t, n, e) ->
let eqs, vars, e = aux_expr vars e false in
eqs, vars, EApp (t, n, e)
| ETriOp (_, TOp_if, _, _, _) ->
raise (PassExn "There should no longer be any condition.")
| EWhen (t, e, e') ->
let eqs, vars, e = aux_expr vars e false in
let eqs', vars, e' = aux_expr vars e' false in
eqs @ eqs', vars, EWhen (t, e, e')
| ETriOp (t, TOp_merge, c, e, e') ->
begin
if toplevel
then
begin
let eqs, vars, c = aux_expr vars c false in
let eqs', vars, e = aux_expr vars e false in
let eqs'', vars, e' = aux_expr vars e' false in
eqs@eqs'@eqs'', vars, ETriOp (t, TOp_merge, c, e, e')
end
else
begin
if List.length t = 1
then
let newvar = Format.sprintf "%s%d" varname_prefix !count in
let newvar =
match List.hd t with
| TInt -> IVar newvar
| TBool -> BVar newvar
| TReal -> RVar newvar
in
let () = incr count in
let vars = (t @ (fst vars), newvar :: (snd vars)) in
let eqs, vars, c = aux_expr vars c false in
let eqs', vars, e = aux_expr vars e false in
let eqs'', vars, e' = aux_expr vars e' false in
((t, [newvar]), ETriOp (t, TOp_merge, c, e, e')) :: eqs @ eqs' @ eqs'', vars, EVar (t, newvar)
else
raise (PassExn "Merges should only happened on unary expressions.")
end
end
in
(** For each node: *)
let aux_merge_lin node =
(** Loop on equations to get additional equations and variables. *)
let eqs, vars =
List.fold_left
(fun (eqs, vars) (patt, expr) ->
let eqs', vars, expr = aux_expr vars expr true in
(patt, expr) :: eqs' @ eqs, vars)
([], node.n_local_vars) node.n_equations
in
Some { node with n_local_vars = vars; n_equations = eqs }
in
node_pass aux_merge_lin
(** [pass_if_removal] replaces the `if` construct with `when` and `merge` ones.
*
* [x1, ..., xn = if c then e_l else e_r;]
* is replaced by:
* (t1, ..., tn) = e_l;
* (u1, ..., un) = e_r;
* (v1, ..., vn) = (t1, ..., tn) when c;
* (w1, ..., wn) = (u1, ..., un) when (not c);
* (x1, ..., xn) = merge c (v1, ..., vn) (w1, ..., wn);
*
* Note that the first two equations (before the use of when) is required in
* order to have the expressions active at each step.
*)
let pass_if_removal verbose debug =
let varcount = ref 0 in (** new variables are called «_ifrem[varcount]» *)
(** Makes a pattern (t_varlist) of fresh variables matching the type t *)
let make_patt t: t_varlist =
(t, List.fold_right
(fun ty acc ->
let nvar: ident = Format.sprintf "_ifrem%d" !varcount in
let nvar =
match ty with
| TInt -> IVar nvar
| TReal -> RVar nvar
| TBool -> BVar nvar
in
incr varcount;
nvar :: acc)
t [])
in
(** If a tuple contains a single element, it should not be. *)
let simplify_tuple t =
match t with
| ETuple (t, [elt]) -> elt
| _ -> t
in
(** For each equation, build a list of equations and a new list of local
* variables as well as an updated version of the original equation. *)
let rec aux_eq vars eq: t_eqlist * t_varlist * t_equation =
let patt, expr = eq in
match expr with
| EConst _ | EVar _ -> [], vars, eq
| EMonOp (t, op, e) ->
let eqs, vars, (patt, e) = aux_eq vars (patt, e) in
eqs, vars, (patt, EMonOp (t, op, e))
| EBinOp (t, op, e, e') ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
let eqs', vars, (_, e') = aux_eq vars (patt, e') in
eqs @ eqs', vars, (patt, EBinOp (t, op, e, e'))
| ETriOp (t, TOp_if, e, e', e'') ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
let eqs', vars, (_, e') = aux_eq vars (patt, e') in
let eqs'', vars, (_, e'') = aux_eq vars (patt, e'') in
let patt_l: t_varlist = make_patt t in
let patt_r: t_varlist = make_patt t in
let patt_l_when: t_varlist = make_patt t in
let patt_r_when: t_varlist = make_patt t in
let expr_l: t_expression =
simplify_tuple
(ETuple
(fst patt_l, List.map (fun v -> EVar (type_var v, v)) (snd patt_l)))
in
let expr_r: t_expression =
simplify_tuple
(ETuple
(fst patt_r, List.map (fun v -> EVar (type_var v, v)) (snd patt_r)))
in
let expr_l_when: t_expression =
simplify_tuple
(ETuple
(fst patt_l_when, List.map (fun v -> EVar (type_var v, v))
(snd patt_l_when)))
in
let expr_r_when: t_expression =
simplify_tuple
(ETuple
(fst patt_r_when, List.map (fun v -> EVar (type_var v, v))
(snd patt_r_when)))
in
let equations: t_eqlist =
[(patt_l, e');
(patt_r, e'');
(patt_l_when,
EWhen (t, expr_l, e));
(patt_r_when,
EWhen (t,
expr_r,
(EMonOp (type_exp e, MOp_not, e))))]
@ eqs @ eqs' @eqs'' in
let vars: t_varlist =
varlist_concat
vars
(varlist_concat patt_l_when (varlist_concat patt_r_when
(varlist_concat patt_r patt_l))) in
let expr =
ETriOp (t, TOp_merge, e, expr_l_when, expr_r_when) in
equations, vars, (patt, expr)
| ETriOp (t, op, e, e', e'') ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
let eqs', vars, (_, e') = aux_eq vars (patt, e') in
let eqs'', vars, (_, e'') = aux_eq vars (patt, e'') in
eqs @ eqs' @ eqs'', vars, (patt, ETriOp (t, op, e, e', e''))
| EComp (t, op, e, e') ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
let eqs', vars, (_, e') = aux_eq vars (patt, e') in
eqs @ eqs', vars, (patt, EComp (t, op, e, e'))
| EWhen (t, e, e') ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
let eqs', vars, (_, e') = aux_eq vars (patt, e') in
eqs @ eqs', vars, (patt, EWhen (t, e, e'))
| EReset (t, e, e') ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
let eqs', vars, (_, e') = aux_eq vars (patt, e') in
eqs @ eqs', vars, (patt, EReset (t, e, e'))
| ETuple (t, l) ->
let eqs, vars, l, _ =
List.fold_right
(fun e (eqs, vars, l, remaining_patt) ->
let patt_l, patt_r = split_patt remaining_patt e in
let eqs', vars, (_, e) = aux_eq vars (patt_l, e) in
eqs' @ eqs, vars, (e :: l), patt_r)
l ([], vars, [], patt) in
eqs, vars, (patt, ETuple (t, l))
| EApp (t, n, e) ->
let eqs, vars, (_, e) = aux_eq vars (patt, e) in
eqs, vars, (patt, EApp (t, n, e))
in
(** For each node, apply the previous function to all equations. *)
let aux_if_removal node =
let new_equations, new_locvars =
List.fold_left
(fun (eqs, vars) eq ->
let eqs', vars, eq = aux_eq vars eq in
eq :: eqs' @ eqs, vars)
([], node.n_local_vars) node.n_equations
in
Some { node with n_equations = new_equations; n_local_vars = new_locvars }
in
node_pass aux_if_removal
(** [pass_linearization_reset] makes sure that all reset constructs in the program
* are applied to functions.
* This is required, since the reset construct is translated into resetting the
* function state in the final C code. *)
let pass_linearization_reset verbose debug =
(** [node_lin] linearises a single node. *)
let node_lin (node: t_node): t_node option =
(** [reset_aux_expression] takes an expression and returns:
* - a list of additional equations
* - the new list of local variables
* - an updated version of the original expression *)
let rec reset_aux_expression vars expr: t_eqlist * t_varlist * t_expression =
match expr with
| EVar _ -> [], vars, expr
| EMonOp (t, op, e) ->
let eqs, vars, e = reset_aux_expression vars e in
eqs, vars, EMonOp (t, op, e)
| EBinOp (t, op, e, e') ->
let eqs, vars, e = reset_aux_expression vars e in
let eqs', vars, e' = reset_aux_expression vars e' in
eqs @ eqs', vars, EBinOp (t, op, e, e')
| ETriOp (t, op, e, e', e'') ->
let eqs, vars, e = reset_aux_expression vars e in
let eqs', vars, e' = reset_aux_expression vars e' in
let eqs'', vars, e'' = reset_aux_expression vars e'' in
eqs @ eqs' @ eqs'', vars, ETriOp (t, op, e, e', e'')
| EComp (t, op, e, e') ->
let eqs, vars, e = reset_aux_expression vars e in
let eqs', vars, e' = reset_aux_expression vars e' in
eqs @ eqs', vars, EComp (t, op, e, e')
| EWhen (t, e, e') ->
let eqs, vars, e = reset_aux_expression vars e in
let eqs', vars, e' = reset_aux_expression vars e' in
eqs @ eqs', vars, EWhen (t, e, e')
| EReset (t, e, e') ->
(
match e with
| EApp (t_app, n_app, e_app) ->
let eqs, vars, e = reset_aux_expression vars e in
eqs, vars, EReset (t, e, e')
| e -> reset_aux_expression vars e
)
| EConst _ -> [], vars, expr
| ETuple (t, l) ->
let eqs, vars, l = List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = reset_aux_expression vars e in
eqs' @ eqs, vars, (e :: l))
l ([], vars, []) in
eqs, vars, ETuple (t, l)
| EApp (t, n, e) ->
let eqs, vars, e = reset_aux_expression vars e in
eqs, vars, EApp (t, n, e)
in
(** Applies the previous function to the expressions of every equation. *)
let new_equations, new_locvars =
List.fold_left
(fun (eqs, vars) (patt, expr) ->
let eqs', vars, expr = reset_aux_expression vars expr in
(patt, expr)::eqs' @ eqs, vars)
([], node.n_local_vars)
node.n_equations
in
Some { node with n_local_vars = new_locvars; n_equations = new_equations }
in
node_pass node_lin
(** [pass_linearization_pre] makes sure that all pre constructs in the program
* are applied to variables.
* This is required, since the pre construct is translated into a variable in
* the final C code. *)
let pass_linearization_pre verbose debug =
(** [node_lin] linearises a single node. *)
let node_lin (node: t_node): t_node option =
(** [pre_aux_expression] takes an expression and returns:
* - a list of additional equations
* - the new list of local variables
* - an updated version of the original expression *)
let rec pre_aux_expression vars expr: t_eqlist * t_varlist * t_expression =
match expr with
| EVar _ -> [], vars, expr
| EMonOp (t, op, e) ->
begin
match op, e with
| MOp_pre, EVar _ ->
let eqs, vars, e = pre_aux_expression vars e in
eqs, vars, EMonOp (t, op, e)
| MOp_pre, _ ->
let eqs, vars, e = pre_aux_expression vars e in
let nvar: string = fresh_var_name vars 6 in
let nvar = match t with
| [TInt] -> IVar nvar
| [TBool] -> BVar nvar
| [TReal] -> RVar nvar
| _ -> failwith "Should not happened. (pass_linearization_pre)" in
let neq_patt: t_varlist = (t, [nvar]) in
let neq_expr: t_expression = e in
let vars = varlist_concat (t, [nvar]) vars in
(neq_patt, neq_expr) :: eqs, vars, EMonOp (t, MOp_pre, EVar (t, nvar))
| _, _ ->
let eqs, vars, e = pre_aux_expression vars e in
eqs, vars, EMonOp (t, op, e)
end
| EBinOp (t, op, e, e') ->
let eqs, vars, e = pre_aux_expression vars e in
let eqs', vars, e' = pre_aux_expression vars e' in
eqs @ eqs', vars, EBinOp (t, op, e, e')
| ETriOp (t, op, e, e', e'') -> (** Do we always want a new var here? *)
let eqs, vars, e = pre_aux_expression vars e in
let nvar: string = fresh_var_name vars 6 in
let nvar: t_var = BVar nvar in
let neq_patt: t_varlist = ([TBool], [nvar]) in
let neq_expr: t_expression = e in
let vars = varlist_concat vars (neq_patt) in
let eqs', vars, e' = pre_aux_expression vars e' in
let eqs'', vars, e'' = pre_aux_expression vars e'' in
(neq_patt, neq_expr) :: eqs @ eqs' @ eqs'', vars, ETriOp (t, op, e, e', e'')
| EComp (t, op, e, e') ->
let eqs, vars, e = pre_aux_expression vars e in
let eqs', vars, e' = pre_aux_expression vars e' in
eqs @ eqs', vars, EComp (t, op, e, e')
| EWhen (t, e, e') ->
let eqs, vars, e = pre_aux_expression vars e in
let eqs', vars, e' = pre_aux_expression vars e' in
eqs @ eqs', vars, EWhen (t, e, e')
| EReset (t, e, e') ->
let eqs, vars, e = pre_aux_expression vars e in
let eqs', vars, e' = pre_aux_expression vars e' in
eqs @ eqs', vars, EReset (t, e, e')
| EConst _ -> [], vars, expr
| ETuple (t, l) ->
let eqs, vars, l = List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = pre_aux_expression vars e in
eqs' @ eqs, vars, (e :: l))
l ([], vars, []) in
eqs, vars, ETuple (t, l)
| EApp (t, n, e) ->
let eqs, vars, e = pre_aux_expression vars e in
eqs, vars, EApp (t, n, e)
in
(** Applies the previous function to the expressions of every equation. *)
let new_equations, new_locvars =
List.fold_left
(fun (eqs, vars) (patt, expr) ->
let eqs', vars, expr = pre_aux_expression vars expr in
(patt, expr)::eqs' @ eqs, vars)
([], node.n_local_vars)
node.n_equations
in
Some { node with n_local_vars = new_locvars; n_equations = new_equations }
in
node_pass node_lin
(** [pass_linearization_tuples] transforms expressions of the form
* (x1, ..., xn) = (e1, ..., em);
* into:
* p1 = e1;
* ...
* pm = em;
* where flatten (p1, ..., pm) = x1, ..., xn
*
* Idem for tuples hidden behind merges and when:
* patt = (...) when c;
* patt = merge c (...) (...);
*)
let pass_linearization_tuples verbose debug ast =
(** [split_tuple] takes an equation and produces an equation list
* corresponding to the [pi = ei;] above. *)
let rec split_tuple (eq: t_equation): t_eqlist =
let patt, expr = eq in
match expr with
| ETuple (_, expr_h :: expr_t) ->
begin
let t_l = type_exp expr_h in
let patt_l, patt_r = list_select (List.length t_l) (snd patt) in
let t_r = List.flatten (List.map type_var patt_r) in
((t_l, patt_l), expr_h) ::
split_tuple ((t_r, patt_r), ETuple (t_r, expr_t))
end
| ETuple (_, []) -> []
| _ -> [eq]
in
(** For each node, apply the previous function to all equations.
* It builds fake equations in order to take care of tuples behind
* merge/when. *)
let aux_linearization_tuples node =
let new_equations = List.flatten
(List.map
(fun eq ->
match snd eq with
| ETuple _ -> split_tuple eq
| EWhen (t, ETuple (_, l), e') ->
List.map
(fun (patt, expr) -> (patt, EWhen (type_exp expr, expr, e')))
(split_tuple (fst eq, ETuple (t, l)))
| ETriOp (t, TOp_merge, c, ETuple (_, l), ETuple (_, l')) ->
begin
if List.length l <> List.length l'
|| List.length t <> List.length (snd (fst eq))
then raise (PassExn "Error while merging tuples.")
else
fst
(List.fold_left2
(fun (eqs, remaining_patt) el er ->
let patt, remaining_patt = split_patt remaining_patt el in
let t = type_exp el in
(patt, ETriOp (t, TOp_merge, c, el, er))
:: eqs, remaining_patt)
([], fst eq) l l')
end
| _ -> [eq])
node.n_equations) in
Some { node with n_equations = new_equations }
in
try node_pass aux_linearization_tuples ast with
| PassExn err -> (debug err; None)
(** [pass_linearization_app] makes sure that any argument to a function is
* either a variable, or of the form [pre _] (which will be translated as a
* variable in the final C code. *)
let pass_linearization_app verbose debug =
let applin_count = ref 0 in (* new variables are called «_applin[varcount]» *)
(** [aux_expr] recursively explores the AST in order to find applications, and
* adds the requires variables and equations. *)
let rec aux_expr vars expr: t_eqlist * t_varlist * t_expression =
match expr with
| EConst _ | EVar _ -> [], vars, expr
| EMonOp (t, op, expr) ->
let eqs, vars, expr = aux_expr vars expr in
eqs, vars, EMonOp (t, op, expr)
| EBinOp (t, op, e, e') ->
let eqs, vars, e = aux_expr vars e in
let eqs', vars, e' = aux_expr vars e' in
eqs @ eqs', vars, EBinOp (t, op, e, e')
| ETriOp (t, op, e, e', e'') ->
let eqs, vars, e = aux_expr vars e in
let eqs', vars, e' = aux_expr vars e' in
let eqs'', vars, e'' = aux_expr vars e'' in
eqs @ eqs' @ eqs'', vars, ETriOp (t, op, e, e', e'')
| EComp (t, op, e, e') ->
let eqs, vars, e = aux_expr vars e in
let eqs', vars, e' = aux_expr vars e' in
eqs @ eqs', vars, EComp (t, op, e, e')
| EWhen (t, e, e') ->
let eqs, vars, e = aux_expr vars e in
let eqs', vars, e' = aux_expr vars e' in
eqs @ eqs', vars, EWhen (t, e, e')
| EReset (t, e, e') ->
let eqs, vars, e = aux_expr vars e in
let eqs', vars, e' = aux_expr vars e' in
eqs @ eqs', vars, EReset (t, e, e')
| ETuple (t, l) ->
let eqs, vars, l =
List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = aux_expr vars e in
eqs' @ eqs, vars, (e :: l))
l ([], vars, []) in
eqs, vars, ETuple (t, l)
| EApp (tout, n, ETuple (tin, l)) ->
let eqs, vars, l =
List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = aux_expr vars e in
match e with
| EVar _ | EMonOp (_, MOp_pre, _) -> (** No need for a new var. *)
eqs' @ eqs, vars, (e :: l)
| _ -> (** Need for a new var. *)
let ty = match type_exp e with
| [ty] -> ty
| _ -> failwith "One should not provide
tuples as arguments to an auxiliary node."
in
let nvar: string = Format.sprintf "_applin%d" !applin_count in
incr applin_count;
let nvar: t_var =
match ty with
| TBool -> BVar nvar
| TInt -> IVar nvar
| TReal -> RVar nvar
in
let neq_patt: t_varlist = ([ty], [nvar]) in
let neq_expr: t_expression = e in
let vars = varlist_concat neq_patt vars in
(neq_patt, neq_expr)::eqs'@eqs, vars, EVar([ty], nvar) :: l)
l ([], vars, []) in
eqs, vars, EApp (tout, n, ETuple (tin, l))
| EApp _ -> failwith "Should not happened (parser)"
in
(** [aux_linearization_app] applies the previous function to every equation *)
let aux_linearization_app node =
let new_equations, new_locvars =
List.fold_left
(fun (eqs, vars) eq ->
let eqs', vars, expr = aux_expr vars (snd eq) in
(fst eq, expr) :: eqs' @ eqs, vars)
([], node.n_local_vars)
node.n_equations
in
Some { node with n_local_vars = new_locvars; n_equations = new_equations }
in
node_pass aux_linearization_app
let pass_ensure_assignment_value verbose debug =
let varcount = ref 0 in
let rec aux_expr should_be_value vars expr =
match expr with
| EConst _ | EVar _ -> [], vars, expr
| EMonOp (t, op, e) ->
let eqs, vars, e = aux_expr true vars e in
eqs, vars, EMonOp (t, op, e)
| EBinOp (t, op, e, e') ->
let eqs, vars, e = aux_expr true vars e in
let eqs', vars, e' = aux_expr true vars e' in
eqs @ eqs', vars, EBinOp (t, op, e, e')
| ETriOp (t, op, e, e', e'') ->
let eqs, vars, e = aux_expr should_be_value vars e in
let eqs', vars, e' = aux_expr should_be_value vars e' in
let eqs'', vars, e'' = aux_expr should_be_value vars e'' in
eqs @ eqs' @ eqs'', vars, ETriOp (t, op, e, e', e'')
| EComp (t, op, e, e') ->
let eqs, vars, e = aux_expr true vars e in
let eqs', vars, e' = aux_expr true vars e' in
eqs @ eqs', vars, EComp (t, op, e, e')
| EWhen (t, e, e') ->
let eqs, vars, e = aux_expr should_be_value vars e in
let eqs', vars, e' = aux_expr should_be_value vars e' in
eqs @ eqs', vars, EWhen (t, e, e')
| EReset (t, e, e') ->
let eqs, vars, e = aux_expr should_be_value vars e in
let eqs', vars, e' = aux_expr should_be_value vars e' in
eqs @ eqs', vars, EReset (t, e, e')
| ETuple (t, l) ->
let eqs, vars, l =
List.fold_right
(fun e (eqs, vars, l) ->
let eqs', vars, e = aux_expr true vars e in
eqs' @ eqs, vars, e :: l)
l ([], vars, []) in
eqs, vars, ETuple (t, l)
| EApp (t, n, e) ->
let eqs, vars, e = aux_expr true vars e in
if should_be_value
then
let nvar = Format.sprintf "_assignval%d" !varcount in
incr varcount;
let nvar: t_var =
match t with
| [TBool] -> BVar nvar
| [TReal] -> RVar nvar
| [TInt] -> IVar nvar
| _ ->
failwith "An application occurring here should return a single element."
in
let neq_patt: t_varlist = (t, [nvar]) in
let neq_expr: t_expression = EApp (t, n, e) in
let vars = varlist_concat neq_patt vars in
(neq_patt, neq_expr) :: eqs, vars, EVar (t, nvar)
else
eqs, vars, EApp (t, n, e)
in
let aux_ensure_assign_val node =
let new_equations, vars =
List.fold_left
(fun (eqs, vars) eq ->
let eqs', vars, expr = aux_expr false vars (snd eq) in
(fst eq, expr) :: eqs' @ eqs, vars
)
([], node.n_local_vars) node.n_equations
in
Some { node with n_equations = new_equations; n_local_vars = vars }
in
node_pass aux_ensure_assign_val
(** [sanity_pass_assignment_unicity] makes sure that there is at most one
* equation defining each variable (and that no equation tries to redefine an
* input).
*
* This is required, since the equations are not ordered in Lustre. *)
let sanity_pass_assignment_unicity verbose debug : t_nodelist -> t_nodelist option =
(** For each node, test the node. *)
let aux (node: t_node) : t_node option =
let incr_aux h n =
match Hashtbl.find_opt h n with
| None -> raise (PassExn "should not happened.")
| Some num -> Hashtbl.replace h n (num + 1)
in
let incr_eq h (((_, patt), _): t_equation) =
List.iter (fun v -> incr_aux h (name_of_var v)) patt
in
let rec incr_eqlist h = function
| [] -> ()
| eq :: eqs -> (incr_eq h eq; incr_eqlist h eqs)
in
let incr_branch h (State (_, eqs, _, _): t_state) = incr_eqlist h eqs in
let incr_automata h ((_, states): t_automaton) =
let acc = Hashtbl.copy h in
List.iter
(fun st ->
let h_st = Hashtbl.copy h in
incr_branch h_st st;
Hashtbl.iter
(fun varname num' ->
match Hashtbl.find_opt acc varname with
| None -> failwith "no!"
| Some num -> Hashtbl.replace acc varname (Int.max num num')
) h_st) states;
Hashtbl.iter (fun v n -> Hashtbl.replace h v n) acc
in
let check_now h : bool=
Hashtbl.fold
(fun varname num old_res ->
if num > 1
then (verbose (Format.asprintf "%s initialized twice!" varname); false)
else old_res) h true
in
(*let purge_initialized h =
Hashtbl.iter
(fun varname num ->
if num > 0
then (verbose (Format.asprintf "Purging %s" varname); Hashtbl.remove h varname)
else ()) h
in*)
let h = Hashtbl.create Config.maxvar in
let add_var n v =
match v with
| IVar s -> Hashtbl.add h s n
| BVar s -> Hashtbl.add h s n
| RVar s -> Hashtbl.add h s n
in
let add_var_in = add_var 1 in
let add_var_loc = add_var 0 in
List.iter add_var_loc (snd node.n_outputs);
List.iter add_var_loc (snd node.n_local_vars);
List.iter add_var_in (snd node.n_inputs);
(** Usual Equations *)
incr_eqlist h node.n_equations;
if check_now h = false
then None
else
begin
List.iter (* 0. *) (incr_automata h) node.n_automata;
if check_now h
then Some node
else None
end
(** never purge -> failwith never executed! purge_initialized h; *)
in
node_pass aux
let rec tpl debug ((pat, exp): t_equation) =
match exp with
| ETuple (_, hexps :: texps) ->
debug "An ETuple has been recognized, inlining...";
let p1, p2 =
list_select
(List.length (type_exp hexps))
(snd pat) in
let t1 = List.flatten (List.map type_var p1) in
let t2 = List.flatten (List.map type_var p2) in
((t1, p1), hexps)
:: (tpl debug ((t2, p2),
ETuple (List.flatten (List.map type_exp texps), texps)))
| ETuple (_, []) -> []
| _ -> [(pat, exp)]
(** [pass_eq_reordering] orders the equation such that an equation should not
* appear before all equations defining the variables it depends on are. *)
let pass_eq_reordering verbose debug ast =
(** [pick_equations] takes a list of equations and initialized variables.
* it either returns:
* - a list of equations in a correct order
* - nothing *)
let rec pick_equations init_vars eqs remaining_equations =
match remaining_equations with
| [] -> (* There are no equations left to order: we are done. *) Some eqs
| _ ->
begin
(** The filter below provides the equations whose dependencies have
* already been defined *)
match List.filter
(fun (patt, expr) ->
List.for_all
(fun v -> List.mem v init_vars)
(vars_of_expr expr))
remaining_equations with
| [] -> (** There are remaining equations to order, but none whose all
* dependencies have already been defined yet.*)
raise (PassExn "[equation ordering] The equations cannot be ordered.")
| h :: t -> (** [h :: t] is a list of equations whose dependencies have
* all already been defined. *)
let init_vars = (* new set of initialized variables *)
List.fold_left
(fun acc vs ->
(vars_of_patt (fst vs)) @ acc) init_vars (h :: t) in
(** The filter below removes the equation of [h :: t] to those to
* the list of equations to be ordered *)
pick_equations init_vars (eqs @ (h :: t))
(List.filter
(fun eq -> List.for_all (fun e -> eq <> e) (h :: t)) remaining_equations)
end
in
(* main function of the (node-)pass. *)
let node_eq_reorganising (node: t_node): t_node option =
let init_vars = List.map name_of_var (snd node.n_inputs) in
try
begin
match pick_equations init_vars [] node.n_equations with
| None -> None
| Some eqs -> Some { node with n_equations = eqs }
end
with PassExn err -> (verbose err; None)
in
(** iterate the pass over the nodes of the program. *)
node_pass node_eq_reorganising ast
let pass_typing verbose debug ast =
let htbl = Hashtbl.create (List.length ast) in
let () = debug "[typing verification]" in
let () = List.iter
(fun n -> Hashtbl.add htbl n.n_name (fst n.n_inputs, fst n.n_outputs))
ast in
let rec check_varlist vl =
let t = fst vl in
let l = snd vl in
match t, l with
| [], [] -> true
| TInt :: t, IVar _ :: l -> check_varlist (t, l)
| TBool :: t, BVar _ :: l -> check_varlist (t, l)
| TReal :: t, RVar _ :: l -> check_varlist (t, l)
| _, _ -> false
in
let rec check_expr vl = function
| EVar (t, v) -> t = type_var v
| EMonOp (t, _, e) -> check_expr vl e && type_exp e = t
| EBinOp (t, _, e, e') -> check_expr vl e && check_expr vl e'
&& t = type_exp e && t = type_exp e'
| ETriOp (t, _, c, e, e') ->
check_expr vl e && check_expr vl e' && check_expr vl c
&& type_exp c = [TBool] && type_exp e = t && type_exp e' = t
| EComp (t, _, e, e') ->
check_expr vl e && check_expr vl e' && t = [TBool]
| EWhen (t, e, e') ->
check_expr vl e && check_expr vl e'
&& t = type_exp e && [TBool] = type_exp e'
| EReset (t, e, e') ->
check_expr vl e && check_expr vl e' && t = type_exp e && type_exp e' = [TBool]
| EConst (t, c) -> type_const c = t
| ETuple (t, l) ->
List.for_all (check_expr vl) l
&& t = List.flatten (List.map type_exp l)
| EApp (t, n, e) ->
check_expr vl e && t = (fst n.n_outputs) && type_exp e = (fst n.n_inputs)
in
let check_equation vl ((peq, eeq): t_equation) =
if check_varlist peq
then
if check_expr vl eeq
then fst peq = type_exp eeq
else false
else false
in
let rec check_equations vl = function
| [] -> true
| eq :: eqs ->
if check_equation vl eq
then check_equations vl eqs
else false
in
let check_one_node node =
check_varlist (node.n_inputs)
&& check_varlist (node.n_outputs)
&& check_varlist (node.n_local_vars)
&& check_equations
(varlist_concat node.n_inputs
(varlist_concat node.n_outputs node.n_local_vars))
node.n_equations
in
let rec aux = function
| [] -> Some ast
| n :: nodes ->
if check_one_node n
then aux nodes
else None
in aux ast
let check_automata_validity verbose debug =
let check_automaton_branch_vars automaton =
let (init, states) = automaton in
let left_side = Hashtbl.create 10 in
let rec init_left_side eqlist = match eqlist with
| [] -> ()
| (varlist, exp)::q ->
begin
Hashtbl.add left_side varlist true;
init_left_side q;
end
in
let check_state s = match s with
| State(name, eqs, cond, next) ->
List.for_all (fun (varlist, exp) -> (Hashtbl.mem left_side varlist)) eqs
in
begin
match init with | State(name, eqs, cond, next) -> init_left_side eqs;
let validity = List.for_all (fun s -> (check_state s)) states in
if not validity then
raise (PassExn "Automaton branch has different variables assignment in different branches")
end
in
let aux node =
try
List.iter check_automaton_branch_vars node.n_automata;
Some node
with
| PassExn err -> (verbose err; None)
in
node_pass aux
let automaton_translation debug automaton =
let id = create_automaton_id () in
let automat_name = create_automaton_name id in
let new_vars = Hashtbl.create Config.maxvar in
let var_seen = Hashtbl.create Config.maxvar in
let var_merged = Hashtbl.create Config.maxvar in
let state_to_int = Hashtbl.create Config.maxvar in
let default_constant ty =
let defaults ty = match ty with
| TInt -> EConst([ty], CInt(0))
| TBool -> EConst([ty], CBool(false))
| TReal -> EConst([ty], CReal(0.0))
in
match ty with
| [TInt] -> EConst(ty, CInt(0))
| [TBool] -> EConst(ty, CBool(false))
| [TReal] -> EConst(ty, CReal(0.0))
| _ -> ETuple(ty, List.map defaults ty)
in
let get_branch_var var branch =
Format.asprintf "_%s_%s_%d" var branch id in
let create_var_name var branch ty =
let s = get_branch_var var branch in
Hashtbl.replace new_vars s (var, branch, ty);
Hashtbl.add var_seen var (s, branch, ty);
s
in
let get_branch_bool branch =
Format.asprintf "_b_%s_%d" branch id in
let create_branch_name branch =
let s = get_branch_bool branch in
Hashtbl.replace new_vars s ("", branch, TBool);
s
in
let create_merge_var varname branch ty =
let s = Format.asprintf "_%s_%s_merge_%d" varname branch id in
Hashtbl.replace new_vars s (varname, branch, ty);
s
in
let create_next_var branch =
let s = Format.asprintf "_next_%s_%d" branch id in
Hashtbl.replace new_vars s ("", branch, TInt);
s
in
let create_type_var_name var branch = match var with
| BVar(name) -> create_var_name name branch TBool
| IVar(name) -> create_var_name name branch TInt
| RVar(name) -> create_var_name name branch TReal
in
let to_var varname ty = match ty with
| TInt -> IVar(varname)
| TBool -> BVar(varname)
| TReal -> RVar(varname)
in
let rec init_state_translation states c = match states with
| [] -> ()
| State(name, _, _, _)::q ->
Hashtbl.replace state_to_int name c; (init_state_translation q (c+1))
in
let rec find_state name =
match Hashtbl.find_opt state_to_int name with
| None -> failwith "Unknown state in automaton"
| Some v -> v
in
let translate_eqlist eqlist branch =
let aux eq =
let ((ty, vlist), expr ) = eq in
((ty, List.map2 (fun l ty -> to_var (create_type_var_name l branch) ty ) vlist ty ),
EWhen(type_exp expr, expr, EVar([TBool], to_var (get_branch_bool branch) TBool )))
in
List.map aux eqlist
in
let rec next_construct exprs nexts = match exprs, nexts with
| [], [] -> EConst([TInt], CInt(1))
| e::exprs, n::nexts -> ETriOp([TInt], TOp_if, e, EConst([TInt], CInt(find_state n)), next_construct exprs nexts)
| _, _ -> failwith "Automata translation: next construct: should not happen"
in
let state_translation state =
match state with
| State( name, equations, expr, next ) ->
let b = create_branch_name name in
let eqs = translate_eqlist equations name in
let bool_expr = EComp([TBool], COp_eq, EVar([TInt], to_var automat_name TInt), EConst([TInt], CInt(find_state name))) in
let next_expr = EWhen([TInt], next_construct expr next, EVar([TBool], to_var (get_branch_bool name) TBool)) in
(([TBool], [to_var b TBool]), bool_expr)::(([TInt], [to_var (create_next_var name) TInt]), next_expr)::eqs
in
let rec iter_states states =
match states with
| [] -> []
| s::q -> (state_translation s) @ (iter_states q)
in
let combine_one_var varname ty =
let default = default_constant [ty] in
let rec merge_branches previous branchlist = match branchlist with
| [] -> Hashtbl.replace var_merged varname true ; [(([ty], [to_var varname ty]), previous)]
| (var, branch, ty2)::q ->
let merge_var = create_merge_var varname branch ty in
(([ty], [to_var merge_var ty]),
ETriOp([ty], TOp_merge, EVar([TBool], to_var (get_branch_bool branch) TBool), EVar([ty], to_var var ty),
EWhen([ty], previous, EMonOp([TBool], MOp_not, EVar([TBool], to_var (get_branch_bool branch) TBool)))))
:: ( merge_branches (EVar([ty], to_var merge_var ty2)) q )
in
let l = Hashtbl.find_all var_seen varname in
merge_branches default l
in
let combine_var varname =
if Hashtbl.mem var_merged varname then []
else let (_, _, ty) = Hashtbl.find var_seen varname in combine_one_var varname ty
in
let rec merge_state states = match states with
| [] -> EConst([TInt], CInt(1))
| State(name, _, _, _)::q ->
let end_state = merge_state q in
let bool_var = EVar([TBool], to_var (get_branch_bool name) TBool) in
ETriOp([TInt], TOp_merge, bool_var, EVar([TInt], to_var (create_next_var name) TInt),
EWhen([TInt], end_state, EMonOp([TBool], MOp_not, bool_var)))
in
let extract_new_var (varname, (_, _, ty)) = to_var varname ty in
let rec build_type varlist = match varlist with
|IVar(_)::q -> TInt::build_type q
|BVar(_)::q -> TBool::build_type q
|RVar(_)::q -> TReal::build_type q
|[] -> []
in
let init, states = automaton in
init_state_translation states 1;
let transition_eq = (([TInt], [IVar(automat_name)]), EBinOp([TInt], BOp_arrow, EConst([TInt], CInt(1)), EMonOp([TInt], MOp_pre, merge_state states))) in
let state_eqs = (iter_states states) in
let new_eqs = state_eqs @ (List.flatten (List.map combine_var (List.of_seq (Hashtbl.to_seq_keys var_seen)))) in
let new_vars = List.map extract_new_var (List.of_seq (Hashtbl.to_seq new_vars)) in
(transition_eq)::new_eqs, (TInt::(build_type new_vars), IVar(automat_name)::new_vars)
let automata_translation_pass verbose debug =
let rec iter_automata autolist = match autolist with
| [] -> [], ([], [])
| a::q -> let (eqs, (ty, vars)) = automaton_translation debug a in
let (eqs_end, (ty_end, vars_end)) = iter_automata q in
eqs@eqs_end, (ty@ty_end, vars@vars_end)
in
let aux node =
try
let eqs, (ty, vars) = iter_automata node.n_automata in
let (ty_old, vars_old) = node.n_local_vars in
Some { node with n_local_vars = (ty@ty_old, vars@vars_old); n_equations = node.n_equations@eqs; n_automata = []}
with
|PassExn err -> (verbose err; None)
in
node_pass aux
let clock_unification_pass verbose debug ast =
let known_clocks = Hashtbl.create 100 in
let used = Hashtbl.create 100 in (*keep track of variables that appear on right side of equation*)
let changed = ref false in
let rec count_not e acc = match e with
| EVar([TBool], var) -> acc, e
| EConst([TBool], cons) -> acc, e
| EMonOp([TBool], MOp_not, e) -> count_not e (acc + 1)
| _ -> acc, e
in
let verify_when e1 e2 =
let n1, var1 = count_not e1 0
and n2, var2 = count_not e2 0 in
if n1 mod 2 <> n2 mod 2 || var1 <> var2 then
raise (PassExn "verify_when failure")
in
let get_var_name var = match var with
| RVar(name)
| BVar(name)
| IVar(name) -> name
in
let rec clk_to_string clk = match clk with
| Base -> "Base"
| Unknown -> "Unknown"
| On(clk, exp) ->
let n, var = count_not exp 0 in
let s = if n mod 2 = 1 then "not " else "" in
let v = match var with |EVar(_, var) -> get_var_name var | EConst(_, CBool(false)) -> "false" |_ -> "true" in
(clk_to_string clk) ^ " on " ^ s ^ v
in
let add_clock var clock =
match Hashtbl.find known_clocks var with
| Unknown -> changed := true; (debug ("Found clock for "^(get_var_name var)^": "^(clk_to_string clock))); Hashtbl.replace known_clocks var clock
| c when c = clock -> ()
| c -> raise (PassExn ("Clock conflict "^(get_var_name var) ^" "^(clk_to_string c) ^ " " ^ (clk_to_string clock)))
in
let rec update_clock exp clk = match exp with
| EConst(_, _) -> ()
| EVar(_, var) -> add_clock var clk; Hashtbl.replace used var var
| EMonOp(_, _, e) -> update_clock e clk
| EComp(_, _, e1, e2)
| EReset(_, e1, e2)
| EBinOp(_, _, e1, e2) -> update_clock e1 clk; update_clock e2 clk
| ETriOp(_, TOp_merge, e1, e2, e3) ->
update_clock e1 clk;
update_clock e2 (On(clk, e1));
update_clock e3 (On(clk, EMonOp([TBool], MOp_not, e1)))
| ETriOp(_, TOp_if, e1, e2, e3) ->
(* The 3 expressions should have the same clock *)
begin
update_clock e1 clk;
update_clock e2 clk;
update_clock e3 clk
end
| ETuple(_, explist) -> List.iter (fun e -> update_clock e clk) explist
| EApp(_, node, e) -> update_clock e clk
| EWhen(_, e1, e2) ->
match clk with
| On(clk2, e) -> verify_when e e2; update_clock e1 clk2
| _ -> raise (PassExn "Clock unification failure: when")
in
let rec propagate_clock eqs =
let rec step ((ty, vars), exp)= match vars with
| [] -> ()
| v::t -> let clk = Hashtbl.find known_clocks v in
begin
if clk <> Unknown then update_clock exp clk
else ();
step ((ty, t), exp)
end
in
List.iter step eqs
in
let rec iter_til_stable eqs =
changed := false;
propagate_clock eqs;
if !changed then
iter_til_stable eqs
in
let check_unification node =
let (_, node_inputs) = node.n_inputs in
let rec check_vars_aux acc = match acc with
| [(v, c)] -> if c = Unknown && (Hashtbl.mem used v) then raise (PassExn ("Clock unification failure: Unkwown clock for "^(get_var_name v))) else c
| (v, t)::q -> let c = check_vars_aux q in
if c <> t then raise (PassExn "Clock unification failure: Non homogeneous equation") else c
| [] -> raise (PassExn "Clock unification failure: empty equation")
in
let rec check_vars ((ty, vars), exp) acc = match vars with
| [] -> let _ = check_vars_aux acc in ()
| v::t -> check_vars ((ty, t), exp) ((v, Hashtbl.find known_clocks v)::acc)
in
let rec check_inputs inputs = match inputs with
| [] -> ()
| i::q -> let c = Hashtbl.find known_clocks i in
match c with
| On(_, e) -> let _, var = count_not e 0 in
begin
match var with
| EConst(_, _) -> ()
| EVar(_, var) -> if not (List.mem var node_inputs) then raise (PassExn "Clock unification failure: input clock depends on non input clock")
else check_inputs q
| _ -> failwith "Should not happen. (clock_unification)"
end
| _ -> check_inputs q
in
(*Check that all variables used have a clock
and that inputs clocks do not depend on local vars or outputs*)
List.iter (fun eq -> check_vars eq []) node.n_equations;
check_inputs node_inputs;
in
let compute_clock_node n =
begin
Hashtbl.clear known_clocks;
List.iter (fun v -> Hashtbl.replace known_clocks v Unknown) (
snd n.n_inputs); (* Initializing inputs to Unknown clock *)
List.iter (fun v -> Hashtbl.replace known_clocks v Unknown) (
snd n.n_local_vars); (* Initializing local variables to Unknown clock *)
List.iter (fun v -> Hashtbl.replace known_clocks v Base) (
snd n.n_outputs); (* Initializing outputs to base clock *)
iter_til_stable n.n_equations;
(* catch potential errors and test for unification *)
check_unification n;
Some n
end
in node_pass compute_clock_node ast