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(*
* Copyright (c) 2009 - 2013 Monoidics ltd.
* Copyright (c) 2013 - present Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*)
open! Utils
(** Re-arrangement and extension of structures with fresh variables *)
module L = Logging
module F = Format
let list_product l1 l2 =
let l1' = IList.rev l1 in
let l2' = IList.rev l2 in
IList.fold_left
(fun acc x -> IList.fold_left (fun acc' y -> (x, y):: acc') acc l2')
[] l1'
let rec list_rev_and_concat l1 l2 =
match l1 with
| [] -> l2
| x1:: l1' -> list_rev_and_concat l1' (x1:: l2)
(** Check whether the index is out of bounds.
If the length is - 1, no check is performed.
If the index is provably out of bound, a bound error is given.
If the length is a constant and the index is not provably in bound, a warning is given.
*)
let check_bad_index pname p len index loc =
let len_is_constant = match len with
| Sil.Const _ -> true
| _ -> false in
let index_provably_out_of_bound () =
let index_too_large = Prop.mk_inequality (Sil.BinOp (Binop.Le, len, index)) in
let index_negative = Prop.mk_inequality (Sil.BinOp (Binop.Le, index, Sil.exp_minus_one)) in
(Prover.check_atom p index_too_large) || (Prover.check_atom p index_negative) in
let index_provably_in_bound () =
let len_minus_one = Sil.BinOp(Binop.PlusA, len, Sil.exp_minus_one) in
let index_not_too_large = Prop.mk_inequality (Sil.BinOp(Binop.Le, index, len_minus_one)) in
let index_nonnegative = Prop.mk_inequality (Sil.BinOp(Binop.Le, Sil.exp_zero, index)) in
Prover.check_zero index || (* index 0 always in bound, even when we know nothing about len *)
((Prover.check_atom p index_not_too_large) && (Prover.check_atom p index_nonnegative)) in
let index_has_bounds () =
match Prover.get_bounds p index with
| Some _, Some _ -> true
| _ -> false in
let get_const_opt = function
| Sil.Const (Const.Cint n) -> Some n
| _ -> None in
if not (index_provably_in_bound ()) then
begin
let len_const_opt = get_const_opt len in
let index_const_opt = get_const_opt index in
if index_provably_out_of_bound () then
let deref_str = Localise.deref_str_array_bound len_const_opt index_const_opt in
let exn =
Exceptions.Array_out_of_bounds_l1
(Errdesc.explain_array_access deref_str p loc, __POS__) in
let pre_opt = State.get_normalized_pre (Abs.abstract_no_symop pname) in
Reporting.log_warning pname ~pre: pre_opt exn
else if len_is_constant then
let deref_str = Localise.deref_str_array_bound len_const_opt index_const_opt in
let desc = Errdesc.explain_array_access deref_str p loc in
let exn = if index_has_bounds ()
then Exceptions.Array_out_of_bounds_l2 (desc, __POS__)
else Exceptions.Array_out_of_bounds_l3 (desc, __POS__) in
let pre_opt = State.get_normalized_pre (Abs.abstract_no_symop pname) in
Reporting.log_warning pname ~pre: pre_opt exn
end
(** Perform bounds checking *)
let bounds_check pname prop len e =
if Config.trace_rearrange then
begin
L.d_str "Bounds check index:"; Sil.d_exp e;
L.d_str " len: "; Sil.d_exp len;
L.d_ln()
end;
check_bad_index pname prop len e
let rec create_struct_values pname tenv orig_prop footprint_part kind max_stamp t
(off: Sil.offset list) inst : Sil.atom list * Sil.strexp * Typ.t =
if Config.trace_rearrange then
begin
L.d_increase_indent 1;
L.d_strln "entering create_struct_values";
L.d_str "typ: "; Typ.d_full t; L.d_ln ();
L.d_str "off: "; Sil.d_offset_list off; L.d_ln (); L.d_ln ()
end;
let new_id () =
incr max_stamp;
Ident.create kind !max_stamp in
let res =
match t, off with
| Typ.Tstruct _, [] ->
([], Sil.Estruct ([], inst), t)
| Typ.Tstruct ({ Typ.instance_fields; static_fields } as struct_typ ),
(Sil.Off_fld (f, _)):: off' ->
let _, t', _ =
try
IList.find (fun (f', _, _) -> Ident.fieldname_equal f f')
(instance_fields @ static_fields)
with Not_found ->
raise (Exceptions.Bad_footprint __POS__) in
let atoms', se', res_t' =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp t' off' inst in
let se = Sil.Estruct ([(f, se')], inst) in
let replace_typ_of_f (f', t', a') =
if Ident.fieldname_equal f f' then (f, res_t', a') else (f', t', a') in
let instance_fields' =
IList.sort Typ.fld_typ_ann_compare (IList.map replace_typ_of_f instance_fields) in
(atoms', se, Typ.Tstruct { struct_typ with Typ.instance_fields = instance_fields'})
| Typ.Tstruct _, (Sil.Off_index e):: off' ->
let atoms', se', res_t' =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp t off' inst in
let e' = Sil.array_clean_new_index footprint_part e in
let len = Sil.Var (new_id ()) in
let se = Sil.Earray (len, [(e', se')], inst) in
let res_t = Typ.Tarray (res_t', None) in
(Sil.Aeq(e, e') :: atoms', se, res_t)
| Typ.Tarray (t', len_), off ->
let len = match len_ with
| None -> Sil.Var (new_id ())
| Some len -> Sil.Const (Const.Cint len) in
(match off with
| [] ->
([], Sil.Earray (len, [], inst), t)
| (Sil.Off_index e) :: off' ->
bounds_check pname orig_prop len e (State.get_loc ());
let atoms', se', res_t' =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp t' off' inst in
let e' = Sil.array_clean_new_index footprint_part e in
let se = Sil.Earray (len, [(e', se')], inst) in
let res_t = Typ.Tarray (res_t', len_) in
(Sil.Aeq(e, e') :: atoms', se, res_t)
| (Sil.Off_fld _) :: _ ->
assert false
)
| Typ.Tint _, [] | Typ.Tfloat _, [] | Typ.Tvoid, [] | Typ.Tfun _, [] | Typ.Tptr _, [] ->
let id = new_id () in
([], Sil.Eexp (Sil.Var id, inst), t)
| Typ.Tint _, [Sil.Off_index e] | Typ.Tfloat _, [Sil.Off_index e]
| Typ.Tvoid, [Sil.Off_index e]
| Typ.Tfun _, [Sil.Off_index e] | Typ.Tptr _, [Sil.Off_index e] ->
(* In this case, we lift t to the t array. *)
let t' = match t with
| Typ.Tptr(t', _) -> t'
| _ -> t in
let len = Sil.Var (new_id ()) in
let atoms', se', res_t' =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp t' [] inst in
let e' = Sil.array_clean_new_index footprint_part e in
let se = Sil.Earray (len, [(e', se')], inst) in
let res_t = Typ.Tarray (res_t', None) in
(Sil.Aeq(e, e'):: atoms', se, res_t)
| Typ.Tint _, _ | Typ.Tfloat _, _ | Typ.Tvoid, _ | Typ.Tfun _, _ | Typ.Tptr _, _ ->
L.d_str "create_struct_values type:"; Typ.d_full t;
L.d_str " off: "; Sil.d_offset_list off; L.d_ln();
raise (Exceptions.Bad_footprint __POS__)
| Typ.Tvar _, _ ->
L.d_str "create_struct_values type:"; Typ.d_full t;
L.d_str " off: "; Sil.d_offset_list off; L.d_ln();
assert false in
if Config.trace_rearrange then
begin
let _, se, _ = res in
L.d_strln "exiting create_struct_values, returning";
Sil.d_sexp se;
L.d_decrease_indent 1;
L.d_ln (); L.d_ln ()
end;
res
(** Extend the strexp by populating the path indicated by [off].
This means that it will add missing flds and do the case - analysis
for array accesses. This does not catch the array - bounds errors.
If we want to implement the checks for array bounds errors,
we need to change this function. *)
let rec _strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp
se typ (off : Sil.offset list) inst =
let new_id () =
incr max_stamp;
Ident.create kind !max_stamp in
match off, se, typ with
| [], Sil.Eexp _, _
| [], Sil.Estruct _, _ ->
[([], se, typ)]
| [], Sil.Earray _, _ ->
let off_new = Sil.Off_index(Sil.exp_zero):: off in
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se typ off_new inst
| (Sil.Off_fld _) :: _, Sil.Earray _, Typ.Tarray _ ->
let off_new = Sil.Off_index(Sil.exp_zero):: off in
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se typ off_new inst
| (Sil.Off_fld (f, _)):: off', Sil.Estruct (fsel, inst'),
Typ.Tstruct ({ Typ.instance_fields; static_fields } as struct_typ) ->
let replace_fv new_v fv = if Ident.fieldname_equal (fst fv) f then (f, new_v) else fv in
let _, typ', _ =
try
IList.find (fun (f', _, _) -> Ident.fieldname_equal f f')
(instance_fields @ static_fields)
with Not_found ->
raise (Exceptions.Missing_fld (f, __POS__)) in
begin
try
let _, se' = IList.find (fun (f', _) -> Ident.fieldname_equal f f') fsel in
let atoms_se_typ_list' =
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se' typ' off' inst in
let replace acc (res_atoms', res_se', res_typ') =
let replace_fse = replace_fv res_se' in
let res_fsel' = IList.sort Sil.fld_strexp_compare (IList.map replace_fse fsel) in
let replace_fta (f, t, a) = let f', t' = replace_fv res_typ' (f, t) in (f', t', a) in
let instance_fields' =
IList.sort Typ.fld_typ_ann_compare (IList.map replace_fta instance_fields) in
let struct_typ =
Typ.Tstruct { struct_typ with Typ.instance_fields = instance_fields' } in
(res_atoms', Sil.Estruct (res_fsel', inst'), struct_typ) :: acc in
IList.fold_left replace [] atoms_se_typ_list'
with Not_found ->
let atoms', se', res_typ' =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp typ' off' inst in
let res_fsel' = IList.sort Sil.fld_strexp_compare ((f, se'):: fsel) in
let replace_fta (f', t', a') = if Ident.fieldname_equal f' f then (f, res_typ', a') else (f', t', a') in
let instance_fields' =
IList.sort Typ.fld_typ_ann_compare (IList.map replace_fta instance_fields) in
let struct_typ = Typ.Tstruct { struct_typ with Typ.instance_fields = instance_fields' } in
[(atoms', Sil.Estruct (res_fsel', inst'), struct_typ)]
end
| (Sil.Off_fld (_, _)):: _, _, _ ->
raise (Exceptions.Bad_footprint __POS__)
| (Sil.Off_index _):: _, Sil.Eexp _, Typ.Tint _
| (Sil.Off_index _):: _, Sil.Eexp _, Typ.Tfloat _
| (Sil.Off_index _):: _, Sil.Eexp _, Typ.Tvoid
| (Sil.Off_index _):: _, Sil.Eexp _, Typ.Tfun _
| (Sil.Off_index _):: _, Sil.Eexp _, Typ.Tptr _
| (Sil.Off_index _):: _, Sil.Estruct _, Typ.Tstruct _ ->
(* L.d_strln_color Orange "turn into an array"; *)
let len = match se with
| Sil.Eexp (_, Sil.Ialloc) -> Sil.exp_one (* if allocated explicitly, we know len is 1 *)
| _ ->
if Config.type_size then Sil.exp_one (* Sil.Sizeof (typ, Sil.Subtype.exact) *)
else Sil.Var (new_id ()) in
let se_new = Sil.Earray (len, [(Sil.exp_zero, se)], inst) in
let typ_new = Typ.Tarray (typ, None) in
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se_new typ_new off inst
| (Sil.Off_index e) :: off', Sil.Earray (len, esel, inst_arr), Typ.Tarray (typ', len_for_typ') ->
bounds_check pname orig_prop len e (State.get_loc ());
begin
try
let _, se' = IList.find (fun (e', _) -> Sil.exp_equal e e') esel in
let atoms_se_typ_list' =
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se' typ' off' inst in
let replace acc (res_atoms', res_se', res_typ') =
let replace_ise ise = if Sil.exp_equal e (fst ise) then (e, res_se') else ise in
let res_esel' = IList.map replace_ise esel in
if (Typ.equal res_typ' typ') || (IList.length res_esel' = 1) then
( res_atoms'
, Sil.Earray (len, res_esel', inst_arr)
, Typ.Tarray (res_typ', len_for_typ') )
:: acc
else
raise (Exceptions.Bad_footprint __POS__) in
IList.fold_left replace [] atoms_se_typ_list'
with Not_found ->
array_case_analysis_index pname tenv orig_prop
footprint_part kind max_stamp
len esel
len_for_typ' typ'
e off' inst_arr inst
end
| _, _, _ ->
raise (Exceptions.Bad_footprint __POS__)
and array_case_analysis_index pname tenv orig_prop
footprint_part kind max_stamp
array_len array_cont
typ_array_len typ_cont
index off inst_arr inst
=
let check_sound t' =
if not (Typ.equal typ_cont t' || array_cont == [])
then raise (Exceptions.Bad_footprint __POS__) in
let index_in_array =
IList.exists (fun (i, _) -> Prover.check_equal Prop.prop_emp index i) array_cont in
let array_is_full =
match array_len with
| Sil.Const (Const.Cint n') -> IntLit.geq (IntLit.of_int (IList.length array_cont)) n'
| _ -> false in
if index_in_array then
let array_default = Sil.Earray (array_len, array_cont, inst_arr) in
let typ_default = Typ.Tarray (typ_cont, typ_array_len) in
[([], array_default, typ_default)]
else if !Config.footprint then begin
let atoms, elem_se, elem_typ =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp typ_cont off inst in
check_sound elem_typ;
let cont_new = IList.sort Sil.exp_strexp_compare ((index, elem_se):: array_cont) in
let array_new = Sil.Earray (array_len, cont_new, inst_arr) in
let typ_new = Typ.Tarray (elem_typ, typ_array_len) in
[(atoms, array_new, typ_new)]
end
else begin
let res_new =
if array_is_full then []
else begin
let atoms, elem_se, elem_typ =
create_struct_values
pname tenv orig_prop footprint_part kind max_stamp typ_cont off inst in
check_sound elem_typ;
let cont_new = IList.sort Sil.exp_strexp_compare ((index, elem_se):: array_cont) in
let array_new = Sil.Earray (array_len, cont_new, inst_arr) in
let typ_new = Typ.Tarray (elem_typ, typ_array_len) in
[(atoms, array_new, typ_new)]
end in
let rec handle_case acc isel_seen_rev = function
| [] -> IList.flatten (IList.rev (res_new:: acc))
| (i, se) as ise :: isel_unseen ->
let atoms_se_typ_list =
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se typ_cont off inst in
let atoms_se_typ_list' =
IList.fold_left (fun acc' (atoms', se', typ') ->
check_sound typ';
let atoms_new = Sil.Aeq (index, i) :: atoms' in
let isel_new = list_rev_and_concat isel_seen_rev ((i, se'):: isel_unseen) in
let array_new = Sil.Earray (array_len, isel_new, inst_arr) in
let typ_new = Typ.Tarray (typ', typ_array_len) in
(atoms_new, array_new, typ_new):: acc'
) [] atoms_se_typ_list in
let acc_new = atoms_se_typ_list' :: acc in
let isel_seen_rev_new = ise :: isel_seen_rev in
handle_case acc_new isel_seen_rev_new isel_unseen in
handle_case [] [] array_cont
end
let exp_has_only_footprint_ids e =
let fav = Sil.exp_fav e in
Sil.fav_filter_ident fav (fun id -> not (Ident.is_footprint id));
Sil.fav_is_empty fav
let laundry_offset_for_footprint max_stamp offs_in =
let rec laundry offs_seen eqs offs =
match offs with
| [] ->
(IList.rev offs_seen, IList.rev eqs)
| (Sil.Off_fld _ as off):: offs' ->
let offs_seen' = off:: offs_seen in
laundry offs_seen' eqs offs'
| (Sil.Off_index(idx) as off):: offs' ->
if exp_has_only_footprint_ids idx then
let offs_seen' = off:: offs_seen in
laundry offs_seen' eqs offs'
else
let () = incr max_stamp in
let fid_new = Ident.create Ident.kfootprint !max_stamp in
let exp_new = Sil.Var fid_new in
let off_new = Sil.Off_index exp_new in
let offs_seen' = off_new:: offs_seen in
let eqs' = (fid_new, idx):: eqs in
laundry offs_seen' eqs' offs' in
laundry [] [] offs_in
let strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp
se te (off : Sil.offset list) inst =
let typ = Sil.texp_to_typ None te in
let off', laundry_atoms =
let off', eqs = laundry_offset_for_footprint max_stamp off in
(* do laundry_offset whether footprint_part is true or not, so max_stamp is modified anyway *)
if footprint_part then
off', IList.map (fun (id, e) -> Prop.mk_eq (Sil.Var id) e) eqs
else off, [] in
if Config.trace_rearrange then
(L.d_str "entering strexp_extend_values se: "; Sil.d_sexp se; L.d_str " typ: ";
Typ.d_full typ; L.d_str " off': "; Sil.d_offset_list off';
L.d_strln (if footprint_part then " FP" else " RE"));
let atoms_se_typ_list =
_strexp_extend_values
pname tenv orig_prop footprint_part kind max_stamp se typ off' inst in
let atoms_se_typ_list_filtered =
let check_neg_atom atom = Prover.check_atom Prop.prop_emp (Prop.atom_negate atom) in
let check_not_inconsistent (atoms, _, _) = not (IList.exists check_neg_atom atoms) in
IList.filter check_not_inconsistent atoms_se_typ_list in
if Config.trace_rearrange then L.d_strln "exiting strexp_extend_values";
let len, st = match te with
| Sil.Sizeof(_, len, st) -> (len, st)
| _ -> None, Sil.Subtype.exact in
IList.map (fun (atoms', se', typ') -> (laundry_atoms @ atoms', se', Sil.Sizeof (typ', len, st)))
atoms_se_typ_list_filtered
let collect_root_offset exp =
let root = Sil.root_of_lexp exp in
let offsets = Sil.exp_get_offsets exp in
(root, offsets)
(** Sil.Construct a points-to predicate for an expression, to add to a footprint. *)
let mk_ptsto_exp_footprint
pname tenv orig_prop (lexp, typ) max_stamp inst : Sil.hpred * Sil.hpred * Sil.atom list =
let root, off = collect_root_offset lexp in
if not (exp_has_only_footprint_ids root)
then begin
(* in angelic mode, purposely ignore dangling pointer warnings during the footprint phase -- we
* will fix them during the re - execution phase *)
if not (Config.angelic_execution && !Config.footprint) then
begin
if Config.developer_mode then
L.err "!!!! Footprint Error, Bad Root : %a !!!! @\n" (Sil.pp_exp pe_text) lexp;
let deref_str = Localise.deref_str_dangling None in
let err_desc =
Errdesc.explain_dereference deref_str orig_prop (State.get_loc ()) in
raise
(Exceptions.Dangling_pointer_dereference
(None, err_desc, __POS__))
end
end;
let off_foot, eqs = laundry_offset_for_footprint max_stamp off in
let st = match !Config.curr_language with
| Config.Clang -> Sil.Subtype.exact
| Config.Java -> Sil.Subtype.subtypes in
let create_ptsto footprint_part off0 = match root, off0, typ with
| Sil.Lvar pvar, [], Typ.Tfun _ ->
let fun_name = Procname.from_string_c_fun (Mangled.to_string (Pvar.get_name pvar)) in
let fun_exp = Sil.Const (Const.Cfun fun_name) in
([], Prop.mk_ptsto root (Sil.Eexp (fun_exp, inst)) (Sil.Sizeof (typ, None, st)))
| _, [], Typ.Tfun _ ->
let atoms, se, t =
create_struct_values
pname tenv orig_prop footprint_part Ident.kfootprint max_stamp typ off0 inst in
(atoms, Prop.mk_ptsto root se (Sil.Sizeof (t, None, st)))
| _ ->
let atoms, se, t =
create_struct_values
pname tenv orig_prop footprint_part Ident.kfootprint max_stamp typ off0 inst in
(atoms, Prop.mk_ptsto root se (Sil.Sizeof (t, None, st))) in
let atoms, ptsto_foot = create_ptsto true off_foot in
let sub = Sil.sub_of_list eqs in
let ptsto = Sil.hpred_sub sub ptsto_foot in
let atoms' = IList.map (fun (id, e) -> Prop.mk_eq (Sil.Var id) e) eqs in
(ptsto, ptsto_foot, atoms @ atoms')
(** Check if the path in exp exists already in the current ptsto predicate.
If it exists, return None. Otherwise, return [Some fld] with [fld] the missing field. *)
let prop_iter_check_fields_ptsto_shallow iter lexp =
let offset = Sil.exp_get_offsets lexp in
let (_, se, _) =
match Prop.prop_iter_current iter with
| Sil.Hpointsto (e, se, t), _ -> (e, se, t)
| _ -> assert false in
let rec check_offset se = function
| [] -> None
| (Sil.Off_fld (fld, _)):: off' ->
(match se with
| Sil.Estruct (fsel, _) ->
(try
let _, se' = IList.find (fun (fld', _) -> Ident.fieldname_equal fld fld') fsel in
check_offset se' off'
with Not_found -> Some fld)
| _ -> Some fld)
| (Sil.Off_index _):: _ -> None in
check_offset se offset
let fav_max_stamp fav =
let max_stamp = ref 0 in
let f id = max_stamp := max !max_stamp (Ident.get_stamp id) in
IList.iter f (Sil.fav_to_list fav);
max_stamp
(** [prop_iter_extend_ptsto iter lexp] extends the current psto
predicate in [iter] with enough fields to follow the path in
[lexp] -- field splitting model. It also materializes all
indices accessed in lexp. *)
let prop_iter_extend_ptsto pname tenv orig_prop iter lexp inst =
if Config.trace_rearrange then
(L.d_str "entering prop_iter_extend_ptsto lexp: "; Sil.d_exp lexp; L.d_ln ());
let offset = Sil.exp_get_offsets lexp in
let max_stamp = fav_max_stamp (Prop.prop_iter_fav iter) in
let max_stamp_val = !max_stamp in
let extend_footprint_pred = function
| Sil.Hpointsto(e, se, te) ->
let atoms_se_te_list =
strexp_extend_values
pname tenv orig_prop true Ident.kfootprint (ref max_stamp_val) se te offset inst in
IList.map (fun (atoms', se', te') -> (atoms', Sil.Hpointsto (e, se', te'))) atoms_se_te_list
| Sil.Hlseg (k, hpara, e1, e2, el) ->
begin
match hpara.Sil.body with
| Sil.Hpointsto(e', se', te'):: body_rest ->
let atoms_se_te_list =
strexp_extend_values
pname tenv orig_prop true Ident.kfootprint
(ref max_stamp_val) se' te' offset inst in
let atoms_body_list =
IList.map (fun (atoms0, se0, te0) -> (atoms0, Sil.Hpointsto(e', se0, te0):: body_rest)) atoms_se_te_list in
let atoms_hpara_list =
IList.map (fun (atoms, body') -> (atoms, { hpara with Sil.body = body'})) atoms_body_list in
IList.map (fun (atoms, hpara') -> (atoms, Sil.Hlseg(k, hpara', e1, e2, el))) atoms_hpara_list
| _ -> assert false
end
| _ -> assert false in
let atoms_se_te_to_iter e (atoms, se, te) =
let iter' = IList.fold_left (Prop.prop_iter_add_atom !Config.footprint) iter atoms in
Prop.prop_iter_update_current iter' (Sil.Hpointsto (e, se, te)) in
let do_extend e se te =
if Config.trace_rearrange then begin
L.d_strln "entering do_extend";
L.d_str "e: "; Sil.d_exp e; L.d_str " se : "; Sil.d_sexp se; L.d_str " te: "; Sil.d_texp_full te;
L.d_ln (); L.d_ln ()
end;
let extend_kind = match e with (* Determine whether to extend the footprint part or just the normal part *)
| Sil.Var id when not (Ident.is_footprint id) -> Ident.kprimed
| Sil.Lvar pvar when Pvar.is_local pvar -> Ident.kprimed
| _ -> Ident.kfootprint in
let iter_list =
let atoms_se_te_list =
strexp_extend_values
pname tenv orig_prop false extend_kind max_stamp se te offset inst in
IList.map (atoms_se_te_to_iter e) atoms_se_te_list in
let res_iter_list =
if Ident.kind_equal extend_kind Ident.kprimed
then iter_list (* normal part already extended: nothing to do *)
else (* extend footprint part *)
let atoms_fp_sigma_list =
let footprint_sigma = Prop.prop_iter_get_footprint_sigma iter in
let sigma_pto, sigma_rest =
IList.partition (function
| Sil.Hpointsto(e', _, _) -> Sil.exp_equal e e'
| Sil.Hlseg (_, _, e1, _, _) -> Sil.exp_equal e e1
| Sil.Hdllseg (_, _, e_iF, _, _, e_iB, _) ->
Sil.exp_equal e e_iF || Sil.exp_equal e e_iB
) footprint_sigma in
let atoms_sigma_list =
match sigma_pto with
| [hpred] ->
let atoms_hpred_list = extend_footprint_pred hpred in
IList.map (fun (atoms, hpred') -> (atoms, hpred' :: sigma_rest)) atoms_hpred_list
| _ ->
L.d_warning "Cannot extend "; Sil.d_exp lexp; L.d_strln " in"; Prop.d_prop (Prop.prop_iter_to_prop iter); L.d_ln();
[([], footprint_sigma)] in
IList.map (fun (atoms, sigma') -> (atoms, IList.stable_sort Sil.hpred_compare sigma')) atoms_sigma_list in
let iter_atoms_fp_sigma_list =
list_product iter_list atoms_fp_sigma_list in
IList.map (fun (iter, (atoms, fp_sigma)) ->
let iter' = IList.fold_left (Prop.prop_iter_add_atom !Config.footprint) iter atoms in
Prop.prop_iter_replace_footprint_sigma iter' fp_sigma
) iter_atoms_fp_sigma_list in
let res_prop_list =
IList.map Prop.prop_iter_to_prop res_iter_list in
begin
L.d_str "in prop_iter_extend_ptsto lexp: "; Sil.d_exp lexp; L.d_ln ();
L.d_strln "prop before:";
let prop_before = Prop.prop_iter_to_prop iter in
Prop.d_prop prop_before; L.d_ln ();
L.d_ln (); L.d_ln ();
L.d_strln "prop list after:";
Propgraph.d_proplist prop_before res_prop_list; L.d_ln ();
L.d_ln (); L.d_ln ();
res_iter_list
end in
begin
match Prop.prop_iter_current iter with
| Sil.Hpointsto (e, se, te), _ -> do_extend e se te
| _ -> assert false
end
(** Add a pointsto for [root(lexp): typ] to the sigma and footprint of a
prop, if it's compatible with the allowed footprint
variables. Then, change it into a iterator. This function ensures
that [root(lexp): typ] is the current hpred of the iterator. typ
is the type of the root of lexp. *)
let prop_iter_add_hpred_footprint_to_prop pname tenv prop (lexp, typ) inst =
let max_stamp = fav_max_stamp (Prop.prop_footprint_fav prop) in
let ptsto, ptsto_foot, atoms =
mk_ptsto_exp_footprint pname tenv prop (lexp, typ) max_stamp inst in
L.d_strln "++++ Adding footprint frame";
Prop.d_prop (Prop.prop_hpred_star Prop.prop_emp ptsto);
L.d_ln (); L.d_ln ();
let eprop = Prop.expose prop in
let foot_sigma = ptsto_foot :: Prop.get_sigma_footprint eprop in
let nfoot_sigma = Prop.sigma_normalize_prop Prop.prop_emp foot_sigma in
let prop' = Prop.normalize (Prop.replace_sigma_footprint nfoot_sigma eprop) in
let prop_new = IList.fold_left (Prop.prop_atom_and ~footprint:!Config.footprint) prop' atoms in
let iter = match (Prop.prop_iter_create prop_new) with
| None ->
let prop_new' = Prop.normalize (Prop.prop_hpred_star prop_new ptsto) in
begin
match (Prop.prop_iter_create prop_new') with
| None -> assert false
| Some iter -> iter
end
| Some iter -> Prop.prop_iter_prev_then_insert iter ptsto in
let offsets_default = Sil.exp_get_offsets lexp in
Prop.prop_iter_set_state iter offsets_default
(** If [lexp] is an access to a field that is annotated with @GuardedBy, add constraints to [prop]
expressing the safety conditions for the access. Complain if these conditions cannot be met. *)
let add_guarded_by_constraints prop lexp pdesc =
let pname = Cfg.Procdesc.get_proc_name pdesc in
let excluded_guardedby_string str =
str = "ui_thread" in (* don't warn on @GuardedBy("ui_thread") *)
let guarded_by_str_is_this guarded_by_str =
string_is_suffix "this" guarded_by_str in
let guarded_by_str_is_class guarded_by_str class_str =
string_is_suffix guarded_by_str (class_str ^ ".class") in
let guarded_by_str_is_current_class guarded_by_str = function
| Procname.Java java_pname ->
(* programmers write @GuardedBy("MyClass.class") when the field is guarded by the class *)
guarded_by_str_is_class guarded_by_str (Procname.java_get_class_name java_pname)
| _ -> false in
(** return true if [guarded_by_str] is "<name_of_current_proc>.this" *)
let guarded_by_str_is_current_class_this guarded_by_str = function
| Procname.Java java_pname ->
guarded_by_str = (Printf.sprintf "%s.this" (Procname.java_get_class_name java_pname))
| _ -> false in
let extract_guarded_by_str item_annot =
let annot_extract_guarded_by_str (annot, _) =
if Annotations.annot_ends_with annot Annotations.guarded_by
then
match annot.Typ.parameters with
| [guarded_by_str] when not (excluded_guardedby_string guarded_by_str) ->
Some guarded_by_str
| _ ->
None
else
None in
IList.find_map_opt annot_extract_guarded_by_str item_annot in
(** if [fld] is annotated with @GuardedBy("mLock"), return mLock *)
let get_guarded_by_fld_str fld typ =
match Annotations.get_field_type_and_annotation fld typ with
| Some (_, item_annot) ->
begin
match extract_guarded_by_str item_annot with
| Some "this" ->
(* expand "this" into <classname>.this *)
Some (Printf.sprintf "%s.this" (Ident.java_fieldname_get_class fld))
| guarded_by_str_opt ->
guarded_by_str_opt
end
| _ -> None in
(* find A.guarded_by_fld_str |-> B and return Some B, or None if there is no such hpred *)
let find_guarded_by_exp guarded_by_str sigma =
let is_guarded_by_strexp (fld, _) =
(* this comparison needs to be somewhat fuzzy, since programmers are free to write
@GuardedBy("mLock"), @GuardedBy("MyClass.mLock"), or use other conventions *)
Ident.fieldname_to_flat_string fld = guarded_by_str ||
Ident.fieldname_to_string fld = guarded_by_str in
IList.find_map_opt
(function
| Sil.Hpointsto ((Const (Cclass clazz) as lhs_exp), _, Sil.Sizeof (typ, _, _))
when guarded_by_str_is_class guarded_by_str (Ident.name_to_string clazz) ->
Some (Sil.Eexp (lhs_exp, Sil.inst_none), typ)
| Sil.Hpointsto (_, Estruct (flds, _), Sil.Sizeof (typ, _, _)) ->
let get_fld_strexp_and_typ f flds =
try
let fld, strexp = IList.find f flds in
begin
match Annotations.get_field_type_and_annotation fld typ with
| Some (fld_typ, _) -> Some (strexp, fld_typ)
| None -> None
end
with Not_found -> None in
begin
(* first, try to find a field that exactly matches the guarded-by string *)
match get_fld_strexp_and_typ is_guarded_by_strexp flds with
| None when guarded_by_str_is_this guarded_by_str ->
(* if the guarded-by string is "OuterClass.this", look for "this$n" for some n.
note that this is a bit sketchy when there are mutliple this$n's, but there's
nothing we can do to disambiguate them. *)
get_fld_strexp_and_typ
(fun (f, _) -> Ident.java_fieldname_is_outer_instance f)
flds
| res ->
res
end
| Sil.Hpointsto (Lvar pvar, rhs_exp, Sil.Sizeof (typ, _, _))
when guarded_by_str_is_current_class_this guarded_by_str pname && Pvar.is_this pvar ->
Some (rhs_exp, typ)
| _ ->
None)
sigma in
(* warn if the access to [lexp] is not protected by the [guarded_by_fld_str] lock *)
let enforce_guarded_access_ accessed_fld guarded_by_str prop =
(* return true if [pdesc] has an annotation that matches [guarded_by_str] *)
let proc_has_matching_annot pdesc guarded_by_str =
let proc_signature =
Annotations.get_annotated_signature (Cfg.Procdesc.get_attributes pdesc) in
let proc_annot, _ = proc_signature.Annotations.ret in
match extract_guarded_by_str proc_annot with
| Some proc_guarded_by_str ->
(* the lock is not held, but the procedure is annotated with @GuardedBy *)
proc_guarded_by_str = guarded_by_str
| None -> false in
let is_synchronized_on_class guarded_by_str =
guarded_by_str_is_current_class guarded_by_str pname &&
Cfg.Procdesc.is_java_synchronized pdesc && Procname.java_is_static pname in
let warn accessed_fld guarded_by_str =
let loc = State.get_loc () in
let err_desc =
Localise.desc_unsafe_guarded_by_access pname accessed_fld guarded_by_str loc in
let exn = Exceptions.Unsafe_guarded_by_access (err_desc, __POS__) in
Reporting.log_error pname exn in
let rec is_read_write_lock typ =
let str_is_read_write_lock str = string_is_suffix "ReadWriteUpdateLock" str in
match typ with
| Typ.Tstruct { struct_name=Some name} -> str_is_read_write_lock (Mangled.to_string name)
| Typ.Tvar name -> str_is_read_write_lock (Typename.to_string name)
| Typ.Tptr (typ, _) -> is_read_write_lock typ
| _ -> false in
let has_lock guarded_by_exp =
(* procedure is synchronized and guarded by this *)
(guarded_by_str_is_current_class_this guarded_by_str pname &&
Cfg.Procdesc.is_java_synchronized pdesc) ||
(guarded_by_str_is_current_class guarded_by_str pname &&
Cfg.Procdesc.is_java_synchronized pdesc && Procname.java_is_static pname) ||
(* or the prop says we already have the lock *)
IList.exists
(function
| Sil.Alocked -> true
| _ -> false)
(Prop.get_exp_attributes prop guarded_by_exp) in
let should_warn pdesc =
Cfg.Procdesc.get_access pdesc <> Sil.Private &&
not (Annotations.pdesc_has_annot pdesc Annotations.visibleForTesting) &&
not (Procname.java_is_access_method (Cfg.Procdesc.get_proc_name pdesc)) in
match find_guarded_by_exp guarded_by_str (Prop.get_sigma prop) with
| Some (Sil.Eexp (guarded_by_exp, _), typ) ->
if is_read_write_lock typ
then
(* TODO: model/understand read-write locks rather than ignoring them *)
prop
else if has_lock guarded_by_exp
then
(* we have the lock; no need to add a proof obligation *)
(* TODO: materialize [fld], but don't add [fld] to the footprint. *)
prop
else
(* we don't know if we have the lock or not. *)
if should_warn pdesc
then
begin
(* non-private method; can't ensure that the lock is held. warn. *)
warn accessed_fld guarded_by_str;
prop
end
else
(* private method. add locked proof obligation to [pdesc] *)
let locked_attr = Sil.Attribute Alocked in
Prop.conjoin_neq ~footprint:true guarded_by_exp locked_attr prop
| _ ->
if not (proc_has_matching_annot pdesc guarded_by_str
|| is_synchronized_on_class guarded_by_str) && should_warn pdesc
then
(* can't find the object the annotation refers to, and procedure is not annotated. warn *)
warn accessed_fld guarded_by_str
else
(* procedure has same GuardedBy annotation as the field. we would like to add a proof
obligation, but we can't (because we can't find an expression corresponding to the
lock in the current prop). so just be silent. *)
();
prop in
let enforce_guarded_access fld typ prop =
match get_guarded_by_fld_str fld typ with
| Some guarded_by_fld_str -> enforce_guarded_access_ fld guarded_by_fld_str prop
| None -> prop in
let check_fld_locks typ prop_acc (fld, strexp) = match strexp with
| Sil.Eexp (exp, _) when Sil.exp_equal exp lexp -> enforce_guarded_access fld typ prop_acc
| _ -> prop_acc in
let hpred_check_flds prop_acc = function
| Sil.Hpointsto (_, Estruct (flds, _), Sizeof (typ, _, _)) ->
IList.fold_left (check_fld_locks typ) prop_acc flds
| _ ->
prop_acc in
match lexp with
| Sil.Lfield (_, fld, typ) ->
(* check for direct access to field annotated with @GuardedBy *)
enforce_guarded_access fld typ prop
| _ ->
(* check for access via alias *)
IList.fold_left hpred_check_flds prop (Prop.get_sigma prop)
(** Add a pointsto for [root(lexp): typ] to the iterator and to the
footprint, if it's compatible with the allowed footprint
variables. This function ensures that [root(lexp): typ] is the
current hpred of the iterator. typ is the type of the root of lexp. *)
let prop_iter_add_hpred_footprint pname tenv orig_prop iter (lexp, typ) inst =
let max_stamp = fav_max_stamp (Prop.prop_iter_footprint_fav iter) in
let ptsto, ptsto_foot, atoms =
mk_ptsto_exp_footprint pname tenv orig_prop (lexp, typ) max_stamp inst in
L.d_strln "++++ Adding footprint frame";
Prop.d_prop (Prop.prop_hpred_star Prop.prop_emp ptsto);
L.d_ln (); L.d_ln ();
let foot_sigma = ptsto_foot :: (Prop.prop_iter_get_footprint_sigma iter) in
let iter_foot = Prop.prop_iter_prev_then_insert iter ptsto in
let iter_foot_atoms = IList.fold_left (Prop.prop_iter_add_atom (!Config.footprint)) iter_foot atoms in
let iter' = Prop.prop_iter_replace_footprint_sigma iter_foot_atoms foot_sigma in
let offsets_default = Sil.exp_get_offsets lexp in
Prop.prop_iter_set_state iter' offsets_default
exception ARRAY_ACCESS
let rearrange_arith lexp prop =
if Config.trace_rearrange then begin
L.d_strln "entering rearrange_arith";
L.d_str "lexp: "; Sil.d_exp lexp; L.d_ln ();
L.d_str "prop: "; L.d_ln (); Prop.d_prop prop; L.d_ln (); L.d_ln ()
end;
if (Config.array_level >= 2) then raise ARRAY_ACCESS
else
let root = Sil.root_of_lexp lexp in
if Prover.check_allocatedness prop root then
raise ARRAY_ACCESS
else
raise (Exceptions.Symexec_memory_error __POS__)
let pp_rearrangement_error message prop lexp =
L.d_strln (".... Rearrangement Error .... " ^ message);
L.d_str "Exp:"; Sil.d_exp lexp; L.d_ln ();
L.d_str "Prop:"; L.d_ln (); Prop.d_prop prop; L.d_ln (); L.d_ln ()
(** do re-arrangment for an iter whose current element is a pointsto *)
let iter_rearrange_ptsto pname tenv orig_prop iter lexp inst =
if Config.trace_rearrange then begin
L.d_increase_indent 1;
L.d_strln "entering iter_rearrange_ptsto";
L.d_str "lexp: "; Sil.d_exp lexp; L.d_ln ();
L.d_strln "prop:"; Prop.d_prop orig_prop; L.d_ln ();
L.d_strln "iter:"; Prop.d_prop (Prop.prop_iter_to_prop iter);
L.d_ln (); L.d_ln ()
end;
let check_field_splitting () =
match prop_iter_check_fields_ptsto_shallow iter lexp with
| None -> ()
| Some fld ->
begin
pp_rearrangement_error "field splitting check failed" orig_prop lexp;
raise (Exceptions.Missing_fld (fld, __POS__))
end in
let res =
if !Config.footprint
then
prop_iter_extend_ptsto pname tenv orig_prop iter lexp inst
else
begin
check_field_splitting ();
match Prop.prop_iter_current iter with
| Sil.Hpointsto (e, se, te), offset ->
let max_stamp = fav_max_stamp (Prop.prop_iter_fav iter) in
let atoms_se_te_list =
strexp_extend_values
pname tenv orig_prop false Ident.kprimed max_stamp se te offset inst in
let handle_case (atoms', se', te') =
let iter' = IList.fold_left (Prop.prop_iter_add_atom !Config.footprint) iter atoms' in
Prop.prop_iter_update_current iter' (Sil.Hpointsto (e, se', te')) in
let filter it =
let p = Prop.prop_iter_to_prop it in
not (Prover.check_inconsistency p) in
IList.filter filter (IList.map handle_case atoms_se_te_list)
| _ -> [iter]
end in
begin
if Config.trace_rearrange then begin
L.d_strln "exiting iter_rearrange_ptsto, returning results";
Prop.d_proplist_with_typ (IList.map Prop.prop_iter_to_prop res);
L.d_decrease_indent 1;
L.d_ln (); L.d_ln ()
end;
res
end
(** do re-arrangment for an iter whose current element is a nonempty listseg *)
let iter_rearrange_ne_lseg recurse_on_iters iter para e1 e2 elist =
if Config.nelseg then
let iter_inductive_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_inst1) = Sil.hpara_instantiate para e1 n' elist in
let hpred_list1 = para_inst1@[Prop.mk_lseg Sil.Lseg_NE para n' e2 elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
let iter_base_case =
let (_, para_inst) = Sil.hpara_instantiate para e1 e2 elist in
Prop.prop_iter_update_current_by_list iter para_inst in
recurse_on_iters [iter_inductive_case; iter_base_case]
else
let iter_inductive_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_inst1) = Sil.hpara_instantiate para e1 n' elist in
let hpred_list1 = para_inst1@[Prop.mk_lseg Sil.Lseg_PE para n' e2 elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
recurse_on_iters [iter_inductive_case]
(** do re-arrangment for an iter whose current element is a nonempty dllseg to be unrolled from lhs *)
let iter_rearrange_ne_dllseg_first recurse_on_iters iter para_dll e1 e2 e3 e4 elist =
let iter_inductive_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_dll_inst1) = Sil.hpara_dll_instantiate para_dll e1 e2 n' elist in
let hpred_list1 = para_dll_inst1@[Prop.mk_dllseg Sil.Lseg_NE para_dll n' e1 e3 e4 elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
let iter_base_case =
let (_, para_dll_inst) = Sil.hpara_dll_instantiate para_dll e1 e2 e3 elist in
let iter' = Prop.prop_iter_update_current_by_list iter para_dll_inst in
let prop' = Prop.prop_iter_to_prop iter' in
let prop'' = Prop.conjoin_eq ~footprint: (!Config.footprint) e1 e4 prop' in
match (Prop.prop_iter_create prop'') with
| None -> assert false
| Some iter' -> iter' in
recurse_on_iters [iter_inductive_case; iter_base_case]
(** do re-arrangment for an iter whose current element is a nonempty dllseg to be unrolled from rhs *)
let iter_rearrange_ne_dllseg_last recurse_on_iters iter para_dll e1 e2 e3 e4 elist =
let iter_inductive_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_dll_inst1) = Sil.hpara_dll_instantiate para_dll e4 n' e3 elist in
let hpred_list1 = para_dll_inst1@[Prop.mk_dllseg Sil.Lseg_NE para_dll e1 e2 e4 n' elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
let iter_base_case =
let (_, para_dll_inst) = Sil.hpara_dll_instantiate para_dll e4 e2 e3 elist in
let iter' = Prop.prop_iter_update_current_by_list iter para_dll_inst in
let prop' = Prop.prop_iter_to_prop iter' in
let prop'' = Prop.conjoin_eq ~footprint: (!Config.footprint) e1 e4 prop' in
match (Prop.prop_iter_create prop'') with
| None -> assert false
| Some iter' -> iter' in
recurse_on_iters [iter_inductive_case; iter_base_case]
(** do re-arrangment for an iter whose current element is a possibly empty listseg *)
let iter_rearrange_pe_lseg recurse_on_iters default_case_iter iter para e1 e2 elist =
let iter_nonemp_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_inst1) = Sil.hpara_instantiate para e1 n' elist in
let hpred_list1 = para_inst1@[Prop.mk_lseg Sil.Lseg_PE para n' e2 elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
let iter_subcases =
let removed_prop = Prop.prop_iter_remove_curr_then_to_prop iter in
let prop' = Prop.conjoin_eq ~footprint: (!Config.footprint) e1 e2 removed_prop in
match (Prop.prop_iter_create prop') with
| None ->
let iter' = default_case_iter (Prop.prop_iter_set_state iter ()) in
[Prop.prop_iter_set_state iter' ()]
| Some iter' -> [iter_nonemp_case; iter'] in
recurse_on_iters iter_subcases
(** do re-arrangment for an iter whose current element is a possibly empty dllseg to be unrolled from lhs *)
let iter_rearrange_pe_dllseg_first recurse_on_iters default_case_iter iter para_dll e1 e2 e3 e4 elist =
let iter_inductive_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_dll_inst1) = Sil.hpara_dll_instantiate para_dll e1 e2 n' elist in
let hpred_list1 = para_dll_inst1@[Prop.mk_dllseg Sil.Lseg_PE para_dll n' e1 e3 e4 elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
let iter_subcases =
let removed_prop = Prop.prop_iter_remove_curr_then_to_prop iter in
let prop' = Prop.conjoin_eq ~footprint: (!Config.footprint) e1 e3 removed_prop in
let prop'' = Prop.conjoin_eq ~footprint: (!Config.footprint) e2 e4 prop' in
match (Prop.prop_iter_create prop'') with
| None ->
let iter' = default_case_iter (Prop.prop_iter_set_state iter ()) in
[Prop.prop_iter_set_state iter' ()]
| Some iter' -> [iter_inductive_case; iter'] in
recurse_on_iters iter_subcases
(** do re-arrangment for an iter whose current element is a possibly empty dllseg to be unrolled from rhs *)
let iter_rearrange_pe_dllseg_last recurse_on_iters default_case_iter iter para_dll e1 e2 e3 e4 elist =
let iter_inductive_case =
let n' = Sil.Var (Ident.create_fresh Ident.kprimed) in
let (_, para_dll_inst1) = Sil.hpara_dll_instantiate para_dll e4 n' e3 elist in
let hpred_list1 = para_dll_inst1@[Prop.mk_dllseg Sil.Lseg_PE para_dll e1 e2 e4 n' elist] in
Prop.prop_iter_update_current_by_list iter hpred_list1 in
let iter_subcases =
let removed_prop = Prop.prop_iter_remove_curr_then_to_prop iter in
let prop' = Prop.conjoin_eq ~footprint: (!Config.footprint) e1 e3 removed_prop in
let prop'' = Prop.conjoin_eq ~footprint: (!Config.footprint) e2 e4 prop' in
match (Prop.prop_iter_create prop'') with
| None ->
let iter' = default_case_iter (Prop.prop_iter_set_state iter ()) in
[Prop.prop_iter_set_state iter' ()]
| Some iter' -> [iter_inductive_case; iter'] in
recurse_on_iters iter_subcases
(** find the type at the offset from the given type expression, if any *)
let type_at_offset texp off =
let rec strip_offset off typ = match off, typ with
| [], _ -> Some typ
| (Sil.Off_fld (f, _)):: off', Typ.Tstruct { Typ.instance_fields } ->
(try
let typ' =
(fun (_, y, _) -> y)
(IList.find (fun (f', _, _) -> Ident.fieldname_equal f f') instance_fields) in
strip_offset off' typ'
with Not_found -> None)
| (Sil.Off_index _) :: off', Typ.Tarray (typ', _) ->
strip_offset off' typ'
| _ -> None in
match texp with
| Sil.Sizeof(typ, _, _) ->
strip_offset off typ
| _ -> None
(** Check that the size of a type coming from an instruction does not exceed the size of the type from the pointsto predicate
For example, that a pointer to int is not used to assign to a char *)
let check_type_size pname prop texp off typ_from_instr =
L.d_strln_color Orange "check_type_size";
L.d_str "off: "; Sil.d_offset_list off; L.d_ln ();
L.d_str "typ_from_instr: "; Typ.d_full typ_from_instr; L.d_ln ();
match type_at_offset texp off with
| Some typ_of_object ->
L.d_str "typ_o: "; Typ.d_full typ_of_object; L.d_ln ();
if Prover.type_size_comparable typ_from_instr typ_of_object && Prover.check_type_size_leq typ_from_instr typ_of_object = false
then begin
let deref_str = Localise.deref_str_pointer_size_mismatch typ_from_instr typ_of_object in
let loc = State.get_loc () in
let exn =
Exceptions.Pointer_size_mismatch (
Errdesc.explain_dereference deref_str prop loc, __POS__) in
let pre_opt = State.get_normalized_pre (Abs.abstract_no_symop pname) in
Reporting.log_warning pname ~pre: pre_opt exn
end
| None ->
L.d_str "texp: "; Sil.d_texp_full texp; L.d_ln ()
(** Exposes lexp |->- from iter. In case that it is not possible to
* expose lexp |->-, this function prints an error message and
* faults. There are four things to note. First, typ is the type of the
* root of lexp. Second, prop should mean the same as iter. Third, the
* result [] means that the given input iter is inconsistent. This
* happens when the theorem prover can prove the inconsistency of prop,
* only after unrolling some predicates in prop. This function ensures
* that the theorem prover cannot prove the inconsistency of any of the
* new iters in the result. *)
let rec iter_rearrange
pname tenv lexp typ_from_instr prop iter
inst: (Sil.offset list) Prop.prop_iter list =
let typ = match Sil.exp_get_offsets lexp with
| Sil.Off_fld (f, ((Typ.Tstruct _) as struct_typ)) :: _ ->
(* access through field: get the struct type from the field *)
if Config.trace_rearrange then begin
L.d_increase_indent 1;
L.d_str "iter_rearrange: root of lexp accesses field "; L.d_strln (Ident.fieldname_to_string f);
L.d_str " type from instruction: "; Typ.d_full typ_from_instr; L.d_ln();
L.d_str " struct type from field: "; Typ.d_full struct_typ; L.d_ln();
L.d_decrease_indent 1;
L.d_ln();
end;
struct_typ
| _ ->
typ_from_instr in
if Config.trace_rearrange then begin
L.d_increase_indent 1;
L.d_strln "entering iter_rearrange";
L.d_str "lexp: "; Sil.d_exp lexp; L.d_ln ();
L.d_str "typ: "; Typ.d_full typ; L.d_ln ();
L.d_strln "prop:"; Prop.d_prop prop; L.d_ln ();
L.d_strln "iter:"; Prop.d_prop (Prop.prop_iter_to_prop iter);
L.d_ln (); L.d_ln ()
end;
let default_case_iter (iter': unit Prop.prop_iter) =
if Config.trace_rearrange then L.d_strln "entering default_case_iter";
if !Config.footprint then
prop_iter_add_hpred_footprint pname tenv prop iter' (lexp, typ) inst
else
if (Config.array_level >= 1 && not !Config.footprint && Sil.exp_pointer_arith lexp)
then rearrange_arith lexp prop
else begin
pp_rearrangement_error "cannot find predicate with root" prop lexp;
if not !Config.footprint then Printer.force_delayed_prints ();
raise (Exceptions.Symexec_memory_error __POS__)
end in
let recurse_on_iters iters =
let f_one_iter iter' =
let prop' = Prop.prop_iter_to_prop iter' in
if Prover.check_inconsistency prop' then []
else iter_rearrange pname tenv (Prop.lexp_normalize_prop prop' lexp) typ prop' iter' inst in
let rec f_many_iters iters_lst = function
| [] -> IList.flatten (IList.rev iters_lst)
| iter':: iters' ->
let iters_res' = f_one_iter iter' in
f_many_iters (iters_res':: iters_lst) iters' in
f_many_iters [] iters in
let filter = function
| Sil.Hpointsto (base, _, _) | Sil.Hlseg (_, _, base, _, _) ->
Prover.is_root prop base lexp
| Sil.Hdllseg (_, _, first, _, _, last, _) ->
let result_first = Prover.is_root prop first lexp in
match result_first with
| None -> Prover.is_root prop last lexp
| Some _ -> result_first in
let res =
match Prop.prop_iter_find iter filter with
| None ->
[default_case_iter iter]
| Some iter ->
match Prop.prop_iter_current iter with
| (Sil.Hpointsto (_, _, texp), off) ->
if Config.type_size then check_type_size pname prop texp off typ_from_instr;
iter_rearrange_ptsto pname tenv prop iter lexp inst
| (Sil.Hlseg (Sil.Lseg_NE, para, e1, e2, elist), _) ->
iter_rearrange_ne_lseg recurse_on_iters iter para e1 e2 elist
| (Sil.Hlseg (Sil.Lseg_PE, para, e1, e2, elist), _) ->
iter_rearrange_pe_lseg recurse_on_iters default_case_iter iter para e1 e2 elist
| (Sil.Hdllseg (Sil.Lseg_NE, para_dll, e1, e2, e3, e4, elist), _) ->
begin
match Prover.is_root prop e1 lexp, Prover.is_root prop e4 lexp with
| None, None -> assert false
| Some _, _ -> iter_rearrange_ne_dllseg_first recurse_on_iters iter para_dll e1 e2 e3 e4 elist
| _, Some _ -> iter_rearrange_ne_dllseg_last recurse_on_iters iter para_dll e1 e2 e3 e4 elist
end
| (Sil.Hdllseg (Sil.Lseg_PE, para_dll, e1, e2, e3, e4, elist), _) ->
begin
match Prover.is_root prop e1 lexp, Prover.is_root prop e4 lexp with
| None, None -> assert false
| Some _, _ -> iter_rearrange_pe_dllseg_first recurse_on_iters default_case_iter iter para_dll e1 e2 e3 e4 elist
| _, Some _ -> iter_rearrange_pe_dllseg_last recurse_on_iters default_case_iter iter para_dll e1 e2 e3 e4 elist
end in
if Config.trace_rearrange then begin
L.d_strln "exiting iter_rearrange, returning results";
Prop.d_proplist_with_typ (IList.map Prop.prop_iter_to_prop res);
L.d_decrease_indent 1;
L.d_ln (); L.d_ln ()
end;
res
(** Check for dereference errors: dereferencing 0, a freed value, or an undefined value *)
let check_dereference_error pdesc (prop : Prop.normal Prop.t) lexp loc =
let nullable_obj_str = ref None in
(* return true if deref_exp is only pointed to by fields/params with @Nullable annotations *)
let is_only_pt_by_nullable_fld_or_param deref_exp =
let ann_sig = Models.get_modelled_annotated_signature (Specs.pdesc_resolve_attributes pdesc) in
IList.for_all
(fun hpred ->
match hpred with
| Sil.Hpointsto (Sil.Lvar pvar, Sil.Eexp (Sil.Var _ as exp, _), _)
when Sil.exp_equal exp deref_exp ->
let is_nullable =
if Annotations.param_is_nullable pvar ann_sig
then
begin
nullable_obj_str := Some (Pvar.to_string pvar);
true
end
else
let is_nullable_attr = function
| Sil.Aretval (pname, ret_attr)
| Sil.Aundef (pname, ret_attr, _, _) when Annotations.ia_is_nullable ret_attr ->
nullable_obj_str := Some (Procname.to_string pname);
true
| _ -> false in
IList.exists is_nullable_attr (Prop.get_exp_attributes prop exp) in
(* it's ok for a non-nullable local to point to deref_exp *)
is_nullable || Pvar.is_local pvar
| Sil.Hpointsto (_, Sil.Estruct (flds, _), Sil.Sizeof (typ, _, _)) ->
let fld_is_nullable fld =
match Annotations.get_field_type_and_annotation fld typ with
| Some (_, annot) -> Annotations.ia_is_nullable annot
| _ -> false in
let is_strexp_pt_by_nullable_fld (fld, strexp) =
match strexp with
| Sil.Eexp (Sil.Var _ as exp, _) when Sil.exp_equal exp deref_exp ->
let is_nullable = fld_is_nullable fld in
if is_nullable then
nullable_obj_str := Some (Ident.fieldname_to_simplified_string fld);
is_nullable
| _ -> true in
IList.for_all is_strexp_pt_by_nullable_fld flds
| _ -> true)
(Prop.get_sigma prop) &&
!nullable_obj_str <> None in
let root = Sil.root_of_lexp lexp in
let is_deref_of_nullable =
let is_definitely_non_null exp prop =
Prover.check_disequal prop exp Sil.exp_zero in
Config.report_nullable_inconsistency && not (is_definitely_non_null root prop)
&& is_only_pt_by_nullable_fld_or_param root in
let relevant_attributes_getters = [
Prop.get_resource_attribute;
Prop.get_undef_attribute;
] in
let get_relevant_attributes exp =
let rec fold_getters = function
| [] -> None
| getter:: tl -> match getter prop exp with
| Some _ as some_attr -> some_attr
| None -> fold_getters tl in
fold_getters relevant_attributes_getters in
let attribute_opt = match get_relevant_attributes root with
| Some att -> Some att
| None -> (* try to remove an offset if any, and find the attribute there *)
let root_no_offset = match root with
| Sil.BinOp((Binop.PlusPI | Binop.PlusA | Binop.MinusPI | Binop.MinusA), base, _) -> base
| _ -> root in
get_relevant_attributes root_no_offset in
if Prover.check_zero (Sil.root_of_lexp root) || is_deref_of_nullable then
begin
let deref_str =
if is_deref_of_nullable then
match !nullable_obj_str with
| Some str -> Localise.deref_str_nullable None str
| None -> Localise.deref_str_nullable None ""
else Localise.deref_str_null None in
let err_desc =
Errdesc.explain_dereference ~use_buckets: true ~is_nullable: is_deref_of_nullable
deref_str prop loc in
if Localise.is_parameter_not_null_checked_desc err_desc then
raise (Exceptions.Parameter_not_null_checked (err_desc, __POS__))
else if Localise.is_field_not_null_checked_desc err_desc then
raise (Exceptions.Field_not_null_checked (err_desc, __POS__))
else if (Localise.is_empty_vector_access_desc err_desc) then
raise (Exceptions.Empty_vector_access (err_desc, __POS__))
else raise (Exceptions.Null_dereference (err_desc, __POS__))
end;
match attribute_opt with
| Some (Sil.Adangling dk) ->
let deref_str = Localise.deref_str_dangling (Some dk) in
let err_desc = Errdesc.explain_dereference deref_str prop (State.get_loc ()) in
raise (Exceptions.Dangling_pointer_dereference (Some dk, err_desc, __POS__))
| Some (Sil.Aundef (s, _, undef_loc, _)) ->
if Config.angelic_execution then ()
else
let deref_str = Localise.deref_str_undef (s, undef_loc) in
let err_desc = Errdesc.explain_dereference deref_str prop loc in
raise (Exceptions.Skip_pointer_dereference (err_desc, __POS__))
| Some (Sil.Aresource ({ Sil.ra_kind = Sil.Rrelease } as ra)) ->
let deref_str = Localise.deref_str_freed ra in
let err_desc = Errdesc.explain_dereference ~use_buckets: true deref_str prop loc in
raise (Exceptions.Use_after_free (err_desc, __POS__))
| _ ->
if Prover.check_equal Prop.prop_emp (Sil.root_of_lexp root) Sil.exp_minus_one then
let deref_str = Localise.deref_str_dangling None in
let err_desc = Errdesc.explain_dereference deref_str prop loc in
raise (Exceptions.Dangling_pointer_dereference (None, err_desc, __POS__))
(* Check that an expression representin an objc block can be null and raise a [B1] null exception.*)
(* It's used to check that we don't call possibly null blocks *)
let check_call_to_objc_block_error pdesc prop fun_exp loc =
let fun_exp_may_be_null () = (* may be null if we don't know if it is definitely not null *)
not (Prover.check_disequal prop (Sil.root_of_lexp fun_exp) Sil.exp_zero) in
let try_explaining_exp e = (* when e is a temp var, try to find the pvar defining e*)
match e with
| Sil.Var id ->
(match (Errdesc.find_ident_assignment (State.get_node ()) id) with
| Some (_, e') -> e'
| None -> e)
| _ -> e in
let get_exp_called () = (* Exp called in the block's function call*)
match State.get_instr () with
| Some Sil.Call(_, Sil.Var id, _, _, _) ->
Errdesc.find_ident_assignment (State.get_node ()) id
| _ -> None in
let is_fun_exp_captured_var () = (* Called expression is a captured variable of the block *)
match get_exp_called () with
| Some (_, Sil.Lvar pvar) -> (* pvar is the block *)
let name = Pvar.get_name pvar in
IList.exists (fun (cn, _) -> (Mangled.to_string name) = (Mangled.to_string cn)) (Cfg.Procdesc.get_captured pdesc)
| _ -> false in
let is_field_deref () = (*Called expression is a field *)
match get_exp_called () with
| Some (_, (Sil.Lfield(e', fn, t))) ->
let e'' = try_explaining_exp e' in
Some (Sil.Lfield(e'', fn, t)), true (* the block dereferences is a field of an object*)
| Some (_, e) -> Some e, false
| _ -> None, false in
if (!Config.curr_language = Config.Clang) &&
fun_exp_may_be_null () &&
not (is_fun_exp_captured_var ()) then
begin
let deref_str = Localise.deref_str_null None in
let err_desc_nobuckets = Errdesc.explain_dereference ~is_nullable: true deref_str prop loc in
match fun_exp with
| Sil.Var id when Ident.is_footprint id ->
let e_opt, is_field_deref = is_field_deref () in
let err_desc_nobuckets' = (match e_opt with
| Some e -> Localise.parameter_field_not_null_checked_desc err_desc_nobuckets e
| _ -> err_desc_nobuckets) in
let err_desc =
Localise.error_desc_set_bucket
err_desc_nobuckets' Localise.BucketLevel.b1 Config.show_buckets in
if is_field_deref then
raise
(Exceptions.Field_not_null_checked
(err_desc, __POS__))
else
raise
(Exceptions.Parameter_not_null_checked
(err_desc, __POS__))
| _ ->
(* HP: fun_exp is not a footprint therefore,
either is a local or it's a modified param *)
let err_desc =
Localise.error_desc_set_bucket
err_desc_nobuckets Localise.BucketLevel.b1 Config.show_buckets in
raise (Exceptions.Null_dereference
(err_desc, __POS__))
end
(** [rearrange lexp prop] rearranges [prop] into the form [prop' * lexp|->strexp:typ].
It returns an iterator with [lexp |-> strexp: typ] as current predicate
and the path (an [offsetlist]) which leads to [lexp] as the iterator state. *)
let rearrange ?(report_deref_errors=true) pdesc tenv lexp typ prop loc
: (Sil.offset list) Prop.prop_iter list =
let nlexp = match Prop.exp_normalize_prop prop lexp with
| Sil.BinOp(Binop.PlusPI, ep, e) -> (* array access with pointer arithmetic *)
Sil.Lindex(ep, e)
| e -> e in
let ptr_tested_for_zero =
Prover.check_disequal prop (Sil.root_of_lexp nlexp) Sil.exp_zero in
let inst = Sil.inst_rearrange (not ptr_tested_for_zero) loc (State.get_path_pos ()) in
L.d_strln ".... Rearrangement Start ....";
L.d_str "Exp: "; Sil.d_exp nlexp; L.d_ln ();
L.d_str "Prop: "; L.d_ln(); Prop.d_prop prop; L.d_ln (); L.d_ln ();
if report_deref_errors then check_dereference_error pdesc prop nlexp (State.get_loc ());
let pname = Cfg.Procdesc.get_proc_name pdesc in
let prop' =
if Config.csl_analysis && !Config.footprint && Procname.is_java pname &&
not (Procname.is_constructor pname || Procname.is_class_initializer pname)
then add_guarded_by_constraints prop lexp pdesc
else prop in
match Prop.prop_iter_create prop' with
| None ->
if !Config.footprint then
[prop_iter_add_hpred_footprint_to_prop pname tenv prop' (nlexp, typ) inst]
else
begin
pp_rearrangement_error "sigma is empty" prop nlexp;
raise (Exceptions.Symexec_memory_error __POS__)
end
| Some iter -> iter_rearrange pname tenv nlexp typ prop' iter inst
(*
let pp_off fmt off =
IList.iter (fun n -> match n with
| Sil.Off_fld (f, t) -> F.fprintf fmt "%a " Ident.pp_fieldname f
| Sil.Off_index e -> F.fprintf fmt "%a " (Sil.pp_exp pe_text) e) off
let sort_ftl ftl =
let compare (f1, _) (f2, _) = Ident.fieldname_compare f1 f2 in
IList.sort compare ftl
*)