Source file `fallback.ml`

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(****************************************************************************)
(*                                                                          *)
(* This file is part of MOPSA, a Modular Open Platform for Static Analysis. *)
(*                                                                          *)
(* Copyright (C) 2017-2019 The MOPSA Project.                               *)
(*                                                                          *)
(* This program is free software: you can redistribute it and/or modify     *)
(* it under the terms of the GNU Lesser General Public License as published *)
(* by the Free Software Foundation, either version 3 of the License, or     *)
(* (at your option) any later version.                                      *)
(*                                                                          *)
(* This program is distributed in the hope that it will be useful,          *)
(* but WITHOUT ANY WARRANTY; without even the implied warranty of           *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            *)
(* GNU Lesser General Public License for more details.                      *)
(*                                                                          *)
(* You should have received a copy of the GNU Lesser General Public License *)
(* along with this program.  If not, see <http://www.gnu.org/licenses/>.    *)
(*                                                                          *)
(****************************************************************************)

(** Fallback transfer functions *)

open Mopsa
open Sig.Abstraction.Stateless
open Universal.Ast
open Ast
open Alarms


module Domain =
struct

  include GenStatelessDomainId(struct let name = "stubs.iterators.fallback" end)

  let checks = []

  let init prog man flow = None
  let ask query man flow = None
  let print_expr man flow printer exp = ()

  let opt_stub_use_forall_loop_eval = ref false
  (** Use fallback evaluation of ∀ formulas with loops *)

  let () = register_builtin_option {
      key      = "-stub-use-forall-loop-evaluation";
      doc      = " use the fallback evaluation of universally quantified formulas with loops";
      category = "Stubs";
      spec     = Set opt_stub_use_forall_loop_eval;
      default  = "";
    }

  let exec_assume_quants quants cond range man flow =
    let rec iter = function
      | [] -> mk_assume cond range
      | (EXISTS,_,_)::tl -> iter tl
      | (FORALL,_,_)::tl when not !opt_stub_use_forall_loop_eval -> iter tl
      | (FORALL,i,S_interval(a,b))::tl ->
        let ii = mk_var i range in
        mk_block [ mk_assign ii a range;
                   mk_while (le ii b range) (
                     mk_block [ iter tl;
                                mk_assign ii (add ii one range) range ] range
                   ) range ] range
      | (_,_,S_resource _)::tl -> assert false
    in
    let stmt = iter quants in
    man.exec stmt flow

  let eval_quantified_formula quants cond range man flow =
    let etrue = exec_assume_quants quants cond range man flow >>% fun flow -> Eval.singleton (mk_true range) flow in
    let nquants,ncond = negate_stub_quantified_formula quants cond in
    let efalse = exec_assume_quants nquants ncond range man flow >>% fun flow -> Eval.singleton (mk_false range) flow  in
    Eval.join etrue efalse

  let eval exp man flow =
    match ekind exp with
    | E_stub_quantified_formula (quants,cond) ->
      eval_quantified_formula quants cond exp.erange man flow |>
      OptionExt.return

    | _ -> None

  let exec stmt man flow = None

end

let () =
  register_stateless_domain (module Domain)