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open Types
open Values
open Expressions
open CfimAst
open Errors
type env_value = Var of VarId.id * typed_value | Abs of abs
type env = env_value list
type 'a eval_result = Stuck | Panic | Res of 'a
type interpreter_mode = ConcreteMode | SymbolicMode
type config = { mode : interpreter_mode; check_invariants : bool }
type stack_frame = { vars : VarId.id list }
(** A function frame
When using the interpreter in concrete mode (i.e, non symbolic) we
push a function frame whenever we enter a function body (and pop it
upon leaving it).
*)
type eval_ctx = {
type_context : type_def TypeDefId.vector;
fun_context : fun_def FunDefId.vector;
type_vars : type_var TypeVarId.vector;
vars : var VarId.Map.t;
frames : stack_frame list;
env : env;
symbolic_counter : SymbolicValueId.generator;
borrow_counter : BorrowId.generator;
}
(** 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_var (ctx : eval_ctx) (vid : VarId.id) : var =
VarId.Map.find vid ctx.vars
(** Retrieve a variable's value in an environment *)
let env_lookup_var_value (env : env) (vid : VarId.id) : typed_value =
let check_ev (ev : env_value) : typed_value option =
match ev with
| Var (vid', v) -> if vid' = vid then Some v else None
| Abs _ -> None
in
match List.find_map check_ev env with
| None -> failwith "Unreachable"
| Some v -> v
(** 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 =
let update_ev (ev : env_value) : env_value =
match ev with
| Var (vid', v) -> if vid' = vid then Var (vid, nv) else Var (vid', v)
| Abs abs -> Abs abs
in
List.map update_ev env
(** 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 }
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