Reviewed By: jeremydubreil Differential Revision: D6458969 fbshipit-source-id: 2c214b3master
Dulma Churchill
7 years ago
committed by
Facebook Github Bot
parent
d25754597d
commit
1d0b6050a6
@ -0,0 +1,200 @@
|
||||
(*
|
||||
* Copyright (c) 2017 - 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.
|
||||
*)
|
||||
module L = Logging
|
||||
module F = Format
|
||||
|
||||
let get_cycle root prop =
|
||||
let sigma = prop.Prop.sigma in
|
||||
let get_points_to e =
|
||||
match e with
|
||||
| Sil.Eexp (e', _) ->
|
||||
List.find
|
||||
~f:(fun hpred ->
|
||||
match hpred with Sil.Hpointsto (e'', _, _) -> Exp.equal e'' e' | _ -> false)
|
||||
sigma
|
||||
| _ ->
|
||||
None
|
||||
in
|
||||
let print_cycle cyc =
|
||||
L.d_str "Cycle= " ;
|
||||
List.iter
|
||||
~f:(fun ((e, t), f, e') ->
|
||||
match (e, e') with
|
||||
| Sil.Eexp (e, _), Sil.Eexp (e', _) ->
|
||||
L.d_str
|
||||
( "(" ^ Exp.to_string e ^ ": " ^ Typ.to_string t ^ ", " ^ Typ.Fieldname.to_string f
|
||||
^ ", " ^ Exp.to_string e' ^ ")" )
|
||||
| _ ->
|
||||
())
|
||||
cyc ;
|
||||
L.d_strln ""
|
||||
in
|
||||
(* Perform a dfs of a graph stopping when e_root is reached.
|
||||
Returns a pair (path, bool) where path is a list of edges ((e1,type_e1),f,e2)
|
||||
describing the path to e_root and bool is true if e_root is reached. *)
|
||||
let rec dfs e_root et_src path el visited =
|
||||
match el with
|
||||
| [] ->
|
||||
(path, false)
|
||||
| (f, e) :: el' ->
|
||||
if Sil.equal_strexp e e_root then ((et_src, f, e) :: path, true)
|
||||
else if List.mem ~equal:Sil.equal_strexp visited e then (path, false)
|
||||
else
|
||||
let visited' = fst et_src :: visited in
|
||||
let res =
|
||||
match get_points_to e with
|
||||
| None ->
|
||||
(path, false)
|
||||
| Some Sil.Hpointsto (_, Sil.Estruct (fl, _), Exp.Sizeof {typ= te}) ->
|
||||
dfs e_root (e, te) ((et_src, f, e) :: path) fl visited'
|
||||
| _ ->
|
||||
(path, false)
|
||||
(* check for lists *)
|
||||
in
|
||||
if snd res then res else dfs e_root et_src path el' visited'
|
||||
in
|
||||
L.d_strln "Looking for cycle with root expression: " ;
|
||||
Sil.d_hpred root ;
|
||||
L.d_strln "" ;
|
||||
match root with
|
||||
| Sil.Hpointsto (e_root, Sil.Estruct (fl, _), Exp.Sizeof {typ= te}) ->
|
||||
let se_root = Sil.Eexp (e_root, Sil.Inone) in
|
||||
(* start dfs with empty path and expr pointing to root *)
|
||||
let pot_cycle, res = dfs se_root (se_root, te) [] fl [] in
|
||||
if res then ( print_cycle pot_cycle ; pot_cycle )
|
||||
else (
|
||||
L.d_strln "NO cycle found from root" ;
|
||||
[] )
|
||||
| _ ->
|
||||
L.d_strln "Root exp is not an allocated object. No cycle found" ;
|
||||
[]
|
||||
|
||||
|
||||
let get_retain_cycle_dotty prop_ cycle =
|
||||
match prop_ with
|
||||
| None ->
|
||||
None
|
||||
| Some Some prop_ ->
|
||||
Dotty.dotty_prop_to_str prop_ cycle
|
||||
| _ ->
|
||||
None
|
||||
|
||||
|
||||
let get_var_retain_cycle prop_ =
|
||||
let sigma = prop_.Prop.sigma in
|
||||
let is_pvar v h =
|
||||
match h with
|
||||
| Sil.Hpointsto (Exp.Lvar _, v', _) when Sil.equal_strexp v v' ->
|
||||
true
|
||||
| _ ->
|
||||
false
|
||||
in
|
||||
let is_hpred_block v h =
|
||||
match (h, v) with
|
||||
| Sil.Hpointsto (e, _, Exp.Sizeof {typ}), Sil.Eexp (e', _)
|
||||
when Exp.equal e e' && Typ.is_block_type typ ->
|
||||
true
|
||||
| _, _ ->
|
||||
false
|
||||
in
|
||||
let find v = List.find ~f:(is_pvar v) sigma |> Option.map ~f:Sil.hpred_get_lhs in
|
||||
let find_block v =
|
||||
if List.exists ~f:(is_hpred_block v) sigma then Some (Exp.Lvar Sil.block_pvar) else None
|
||||
in
|
||||
let sexp e = Sil.Eexp (e, Sil.Inone) in
|
||||
let find_or_block ((e, t), f, e') =
|
||||
match find e with
|
||||
| Some pvar ->
|
||||
[((sexp pvar, t), f, e')]
|
||||
| _ ->
|
||||
match find_block e with
|
||||
| Some blk ->
|
||||
[((sexp blk, t), f, e')]
|
||||
| _ ->
|
||||
let sizeof = {Exp.typ= t; nbytes= None; dynamic_length= None; subtype= Subtype.exact} in
|
||||
[((sexp (Exp.Sizeof sizeof), t), f, e')]
|
||||
in
|
||||
(* returns the pvars of the first cycle we find in sigma.
|
||||
This is an heuristic that works if there is one cycle.
|
||||
In case there are more than one cycle we may return not necessarily
|
||||
the one we are looking for. *)
|
||||
let rec do_sigma sigma_todo =
|
||||
match sigma_todo with
|
||||
| [] ->
|
||||
[]
|
||||
| hp :: sigma' ->
|
||||
let cycle = get_cycle hp prop_ in
|
||||
L.d_strln "Filtering pvar in cycle " ;
|
||||
let cycle' = List.concat_map ~f:find_or_block cycle in
|
||||
if List.is_empty cycle' then do_sigma sigma' else cycle'
|
||||
in
|
||||
do_sigma sigma
|
||||
|
||||
|
||||
(** Checks if cycle has fields (derived from a property or directly defined as ivar) with attributes
|
||||
weak/unsafe_unretained/assing *)
|
||||
let cycle_has_weak_or_unretained_or_assign_field tenv cycle =
|
||||
(* returns items annotation for field fn in struct t *)
|
||||
let get_item_annotation (t: Typ.t) fn =
|
||||
match t.desc with
|
||||
| Tstruct name
|
||||
-> (
|
||||
let equal_fn (fn', _, _) = Typ.Fieldname.equal fn fn' in
|
||||
match Tenv.lookup tenv name with
|
||||
| Some {fields; statics} ->
|
||||
List.find ~f:equal_fn (fields @ statics) |> Option.value_map ~f:trd3 ~default:[]
|
||||
| None ->
|
||||
[] )
|
||||
| _ ->
|
||||
[]
|
||||
in
|
||||
let rec has_weak_or_unretained_or_assign params =
|
||||
match params with
|
||||
| [] ->
|
||||
false
|
||||
| att :: _
|
||||
when String.equal Config.unsafe_unret att || String.equal Config.weak att
|
||||
|| String.equal Config.assign att ->
|
||||
true
|
||||
| _ :: params' ->
|
||||
has_weak_or_unretained_or_assign params'
|
||||
in
|
||||
let do_annotation ((a: Annot.t), _) =
|
||||
( String.equal a.class_name Config.property_attributes
|
||||
|| String.equal a.class_name Config.ivar_attributes )
|
||||
&& has_weak_or_unretained_or_assign a.parameters
|
||||
in
|
||||
let rec do_cycle c =
|
||||
match c with
|
||||
| [] ->
|
||||
false
|
||||
| ((_, t), fn, _) :: c' ->
|
||||
let ia = get_item_annotation t fn in
|
||||
if List.exists ~f:do_annotation ia then true else do_cycle c'
|
||||
in
|
||||
do_cycle cycle
|
||||
|
||||
|
||||
let exn_retain_cycle original_prop hpred cycle =
|
||||
let cycle_dotty = get_retain_cycle_dotty original_prop cycle in
|
||||
let desc = Errdesc.explain_retain_cycle cycle (State.get_loc ()) cycle_dotty in
|
||||
Exceptions.Retain_cycle (hpred, desc, __POS__)
|
||||
|
||||
|
||||
let report_cycle tenv hpred original_prop =
|
||||
(* When there is a cycle in objc we ignore it
|
||||
only if it's empty or it has weak or unsafe_unretained fields.
|
||||
Otherwise we report a retain cycle. *)
|
||||
let remove_opt prop_ = match prop_ with Some Some p -> p | _ -> Prop.prop_emp in
|
||||
let cycle = get_var_retain_cycle (remove_opt original_prop) in
|
||||
let ignore_cycle =
|
||||
Int.equal (List.length cycle) 0 || cycle_has_weak_or_unretained_or_assign_field tenv cycle
|
||||
in
|
||||
(ignore_cycle, exn_retain_cycle original_prop hpred cycle)
|
||||
|
||||
@ -0,0 +1,10 @@
|
||||
(*
|
||||
* Copyright (c) 2017 - 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.
|
||||
*)
|
||||
|
||||
val report_cycle : Tenv.t -> Sil.hpred -> Prop.normal Prop.t option option -> bool * exn
|
||||
@ -0,0 +1,50 @@
|
||||
/*
|
||||
* Copyright (c) 2017 - 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.
|
||||
*/
|
||||
#import <Foundation/NSObject.h>
|
||||
|
||||
@class AFeed;
|
||||
|
||||
@interface Adapter : NSObject
|
||||
|
||||
@property(nonatomic, strong) AFeed* feed;
|
||||
|
||||
@end
|
||||
|
||||
@implementation Adapter
|
||||
|
||||
@end
|
||||
|
||||
@interface AFeed : NSObject
|
||||
|
||||
@property(nonatomic, weak) Adapter* adapter;
|
||||
|
||||
@end
|
||||
|
||||
@implementation AFeed
|
||||
|
||||
@end
|
||||
|
||||
@interface RetainCycleExampleWeak : NSObject
|
||||
|
||||
@property(nonatomic, strong) AFeed* feed;
|
||||
|
||||
@end
|
||||
|
||||
@implementation RetainCycleExampleWeak
|
||||
|
||||
- (void)test {
|
||||
_feed.adapter.feed = _feed;
|
||||
}
|
||||
|
||||
- (void)main1 {
|
||||
RetainCycleExampleWeak* b = [RetainCycleExampleWeak new];
|
||||
[b test];
|
||||
}
|
||||
|
||||
@end
|
||||
Loading…
Reference in new issue