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open Types
open Values
open CfimAst
module V = Values
type binder = {
index : VarId.id; (** Unique variable identifier *)
name : string option; (** Possible name *)
}
[@@deriving show]
(** A binder used in an environment, to map a variable to a value *)
(** Environment value: mapping from variable to value, abstraction (only
used in symbolic mode) or stack frame delimiter.
TODO: rename? Environment element or something?
*)
type env_value = Var of binder * typed_value | Abs of abs | Frame
[@@deriving show]
type env = env_value list [@@deriving show]
type interpreter_mode = ConcreteMode | SymbolicMode [@@deriving show]
type config = { mode : interpreter_mode; check_invariants : bool }
[@@deriving show]
type eval_ctx = {
type_context : type_def list;
fun_context : fun_def list;
type_vars : type_var list;
env : env;
symbolic_counter : SymbolicValueId.generator;
borrow_counter : BorrowId.generator;
}
[@@deriving show]
(** Evaluation context *)
let fresh_symbolic_value_id (ctx : eval_ctx) : eval_ctx * SymbolicValueId.id =
let id, counter' = SymbolicValueId.fresh ctx.symbolic_counter in
({ ctx with symbolic_counter = counter' }, id)
let fresh_borrow_id (ctx : eval_ctx) : eval_ctx * BorrowId.id =
let id, counter' = BorrowId.fresh ctx.borrow_counter in
({ ctx with borrow_counter = counter' }, id)
let lookup_type_var (ctx : eval_ctx) (vid : TypeVarId.id) : type_var =
TypeVarId.nth ctx.type_vars vid
let ctx_lookup_binder (ctx : eval_ctx) (vid : VarId.id) : binder =
(* TOOD: we might want to stop at the end of the frame *)
let rec lookup env =
match env with
| [] ->
raise (Invalid_argument ("Variable not found: " ^ VarId.to_string vid))
| Var (var, _) :: env' -> if var.index = vid then var else lookup env'
| (Abs _ | Frame) :: env' -> lookup env'
in
lookup ctx.env
let ctx_lookup_type_def (ctx : eval_ctx) (tid : TypeDefId.id) : type_def =
TypeDefId.nth ctx.type_context tid
let ctx_lookup_fun_def (ctx : eval_ctx) (fid : FunDefId.id) : fun_def =
FunDefId.nth ctx.fun_context fid
(** Retrieve a variable's value in an environment *)
let env_lookup_var_value (env : env) (vid : VarId.id) : typed_value =
(* We take care to stop at the end of current frame: different variables
in different frames can have the same id!
*)
let rec lookup env =
match env with
| [] -> failwith "Unexpected"
| Var (var, v) :: env' -> if var.index = vid then v else lookup env'
| Abs _ :: env' -> lookup env'
| Frame :: _ -> failwith "End of frame"
in
lookup env
(** Retrieve a variable's value in an evaluation context *)
let ctx_lookup_var_value (ctx : eval_ctx) (vid : VarId.id) : typed_value =
env_lookup_var_value ctx.env vid
(** Update a variable's value in an environment
This is a helper function: it can break invariants and doesn't perform
any check.
*)
let env_update_var_value (env : env) (vid : VarId.id) (nv : typed_value) : env =
(* We take care to stop at the end of current frame: different variables
in different frames can have the same id!
*)
let rec update env =
match env with
| [] -> failwith "Unexpected"
| Var (var, v) :: env' ->
if var.index = vid then Var (var, nv) :: env'
else Var (var, v) :: update env'
| Abs abs :: env' -> Abs abs :: update env'
| Frame :: _ -> failwith "End of frame"
in
update env
let var_to_binder (var : var) : binder = { index = var.index; name = var.name }
(** Update a variable's value in an evaluation context.
This is a helper function: it can break invariants and doesn't perform
any check.
*)
let ctx_update_var_value (ctx : eval_ctx) (vid : VarId.id) (nv : typed_value) :
eval_ctx =
{ ctx with env = env_update_var_value ctx.env vid nv }
(** Push a variable in the context's environment.
Checks that the pushed variable and its value have the same type (this
is important).
*)
let ctx_push_var (ctx : eval_ctx) (var : var) (v : typed_value) : eval_ctx =
assert (var.var_ty = v.ty);
let bv = var_to_binder var in
{ ctx with env = Var (bv, v) :: ctx.env }
(** Push a list of variables.
Checks that the pushed variables and their values have the same type (this
is important).
*)
let ctx_push_vars (ctx : eval_ctx) (vars : (var * typed_value) list) : eval_ctx
=
assert (List.for_all (fun (var, value) -> var.var_ty = value.ty) vars);
let vars =
List.map (fun (var, value) -> Var (var_to_binder var, value)) vars
in
let vars = List.rev vars in
{ ctx with env = List.append vars ctx.env }
let mk_bottom (ty : ety) : typed_value = { value = Bottom; ty }
(** Push an uninitialized variable (which thus maps to [Bottom]) *)
let ctx_push_uninitialized_var (ctx : eval_ctx) (var : var) : eval_ctx =
ctx_push_var ctx var (mk_bottom var.var_ty)
(** Push a list of uninitialized variables (which thus map to [Bottom]) *)
let ctx_push_uninitialized_vars (ctx : eval_ctx) (vars : var list) : eval_ctx =
let vars = List.map (fun v -> (v, mk_bottom v.var_ty)) vars in
ctx_push_vars ctx vars
(** Visitor to iterate over the values in the current frame *)
class ['self] iter_frame_concrete =
object (self : 'self)
inherit [_] V.iter_typed_value
method visit_env_value_Var : 'acc -> binder -> typed_value -> unit =
fun acc vid v -> self#visit_typed_value acc v
method visit_env : 'acc -> env -> unit =
fun acc env ->
match env with
| [] -> ()
| Var (vid, v) :: env ->
self#visit_env_value_Var acc vid v;
self#visit_env acc env
| Abs _ :: _ -> failwith "Unexpected abstraction"
| Frame :: _ -> (* We stop here *) ()
end
(** Visitor to iterate over the values in an environment (we explore an
environment until we find the end of the current frame) *)
class ['self] iter_env_concrete =
object (self : 'self)
inherit [_] V.iter_typed_value
method visit_env_value_Var : 'acc -> binder -> typed_value -> unit =
fun acc vid v -> self#visit_typed_value acc v
method visit_env : 'acc -> env -> unit =
fun acc env ->
match env with
| [] -> ()
| Var (vid, v) :: env ->
self#visit_env_value_Var acc vid v;
self#visit_env acc env
| Abs _ :: _ -> failwith "Unexpected abstraction"
| Frame :: env -> self#visit_env acc env
end
(** Visitor to map over the values in the current frame *)
class ['self] map_frame_concrete =
object (self : 'self)
inherit [_] V.map_typed_value
method visit_env_value_Var : 'acc -> binder -> typed_value -> env_value =
fun acc vid v ->
let v = self#visit_typed_value acc v in
Var (vid, v)
method visit_env : 'acc -> env -> env =
fun acc env ->
match env with
| [] -> []
| Var (vid, v) :: env ->
let v = self#visit_env_value_Var acc vid v in
let env = self#visit_env acc env in
v :: env
| Abs _ :: _ -> failwith "Unexpected abstraction"
| Frame :: env -> (* We stop here *) Frame :: env
end
(** Visitor to iterate over the values in an environment (we explore an
environment until we find the end of the current frame) *)
class ['self] map_env_concrete =
object (self : 'self)
inherit [_] V.map_typed_value
method visit_env_value_Var : 'acc -> binder -> typed_value -> env_value =
fun acc vid v ->
let v = self#visit_typed_value acc v in
Var (vid, v)
method visit_env : 'acc -> env -> env =
fun acc env ->
match env with
| [] -> []
| Var (vid, v) :: env ->
let v = self#visit_env_value_Var acc vid v in
let env = self#visit_env acc env in
v :: env
| Abs _ :: _ -> failwith "Unexpected abstraction"
| Frame :: env -> Frame :: self#visit_env acc env
end
|
