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|
(**************************************************************************)
(* Sail *)
(* *)
(* Copyright (c) 2013-2017 *)
(* Kathyrn Gray *)
(* Shaked Flur *)
(* Stephen Kell *)
(* Gabriel Kerneis *)
(* Robert Norton-Wright *)
(* Christopher Pulte *)
(* Peter Sewell *)
(* Alasdair Armstrong *)
(* Brian Campbell *)
(* Thomas Bauereiss *)
(* Anthony Fox *)
(* Jon French *)
(* Dominic Mulligan *)
(* Stephen Kell *)
(* Mark Wassell *)
(* *)
(* All rights reserved. *)
(* *)
(* This software was developed by the University of Cambridge Computer *)
(* Laboratory as part of the Rigorous Engineering of Mainstream Systems *)
(* (REMS) project, funded by EPSRC grant EP/K008528/1. *)
(* *)
(* Redistribution and use in source and binary forms, with or without *)
(* modification, are permitted provided that the following conditions *)
(* are met: *)
(* 1. Redistributions of source code must retain the above copyright *)
(* notice, this list of conditions and the following disclaimer. *)
(* 2. Redistributions in binary form must reproduce the above copyright *)
(* notice, this list of conditions and the following disclaimer in *)
(* the documentation and/or other materials provided with the *)
(* distribution. *)
(* *)
(* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' *)
(* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED *)
(* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A *)
(* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR *)
(* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, *)
(* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT *)
(* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF *)
(* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND *)
(* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, *)
(* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT *)
(* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF *)
(* SUCH DAMAGE. *)
(**************************************************************************)
open Ast
open Ast_util
let opt_nl_flow = ref false
let rec escapes (E_aux (aux, _)) =
match aux with
| E_throw _ -> true
| E_block [] -> false
| E_block exps -> escapes (List.hd (List.rev exps))
| _ -> false
let rec returns (E_aux (aux, _)) =
match aux with
| E_return _ -> true
| E_block [] -> false
| E_block exps -> returns (List.hd (List.rev exps))
| _ -> false
let is_assert (E_aux (aux, _)) =
match aux with
| E_assert _ -> true
| _ -> false
let is_bitvector_literal (L_aux (aux, _)) =
match aux with
| L_bin _ | L_hex _ -> true
| _ -> false
let bitvector_unsigned (L_aux (aux, _)) =
let open Sail_lib in
match aux with
| L_bin str -> uint (List.map bin_char (Util.string_to_list str))
| L_hex str -> uint (bits_of_string str)
| _ -> assert false
let rec pat_id (P_aux (aux, _)) =
match aux with
| P_id id -> Some id
| P_as (_, id) -> Some id
| P_var (pat, _) -> pat_id pat
| _ -> None
let add_assert cond (E_aux (aux, (l, ())) as exp) =
let msg = mk_lit_exp (L_string "") in
let assertion = locate (fun _ -> gen_loc l) (mk_exp (E_assert (cond, msg))) in
match aux with
| E_block exps -> E_aux (E_block (assertion :: exps), (l, ()))
| _ -> E_aux (E_block (assertion :: [exp]), (l, ()))
(* If we know that x != bitv, then after any let y = unsigned(x) we
will also know that y != unsigned(bitv) *)
let modify_unsigned id value (E_aux (aux, annot) as exp) =
match aux with
| E_let (LB_aux (LB_val (pat, E_aux (E_app (f, [E_aux (E_id id', _)]), _)), _) as lb, exp')
when (string_of_id f = "unsigned" || string_of_id f = "UInt") && Id.compare id id' = 0 ->
begin match pat_id pat with
| None -> exp
| Some uid ->
E_aux (E_let (lb,
add_assert (mk_exp (E_app_infix (mk_exp (E_id uid), mk_id "!=", mk_lit_exp (L_num value)))) exp'),
annot)
end
| _ -> exp
let analyze' exps =
match exps with
| E_aux (E_if (cond, then_exp, _), _) :: rest when escapes then_exp ->
begin match cond with
| E_aux (E_app_infix (E_aux (E_id id, _), op, E_aux (E_lit lit, _)), _)
| E_aux (E_app_infix (E_aux (E_lit lit, _), op, E_aux (E_id id, _)), _)
when string_of_id op = "==" && is_bitvector_literal lit ->
let value = bitvector_unsigned lit in
List.map (modify_unsigned id value) exps
| _ -> exps
end
| (E_aux (E_if (cond, then_exp, _), (l, _)) as exp) :: next :: rest
when returns then_exp && not (is_assert next) ->
let msg = mk_lit_exp (L_string "") in
let not_cond = locate (fun _ -> gen_loc l) (mk_exp (E_app (mk_id "not_bool", [cond]))) in
let assertion = locate (fun _ -> gen_loc l) (mk_exp (E_assert (not_cond, msg))) in
exp :: assertion :: next :: rest
| _ -> exps
let analyze exps =
if !opt_nl_flow then analyze' exps else exps
|
