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Relational: Use same invalidation strategy as base #1646

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79 changes: 41 additions & 38 deletions src/analyses/apron/relationAnalysis.apron.ml
Original file line number Diff line number Diff line change
Expand Up @@ -469,10 +469,9 @@ struct
| None -> None
| Some st ->
let ad = ask.f (Queries.ReachableFrom e) in
if Queries.AD.is_top ad then
None
else
Some (Queries.AD.join ad st)
(* See https://github.com/goblint/analyzer/issues/1535 *)
let ad = Queries.AD.remove UnknownPtr ad in
Some (Queries.AD.join ad st)
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in
List.fold_right reachable es (Some (Queries.AD.empty ()))

Expand Down Expand Up @@ -513,6 +512,36 @@ struct
if RD.is_bot_env res then raise Deadcode;
{st with rel = res}

let special_unknown_invalidate man f args =
(* No warning here, base already prodcues the appropriate warnings *)
let desc = LibraryFunctions.find f in
let shallow_addrs = LibraryDesc.Accesses.find desc.accs { kind = Write; deep = false } args in
let deep_addrs = LibraryDesc.Accesses.find desc.accs { kind = Write; deep = true } args in
let deep_addrs =
if List.mem LibraryDesc.InvalidateGlobals desc.attrs then (
foldGlobals !Cilfacade.current_file (fun acc global ->
match global with
| GVar (vi, _, _) when not (BaseUtil.is_static vi) ->
mkAddrOf (Var vi, NoOffset) :: acc
(* TODO: what about GVarDecl? *)
| _ -> acc
) deep_addrs
)
else
deep_addrs
in
let lvallist e =
match man.ask (Queries.MayPointTo e) with
| ad when Queries.AD.is_top ad -> []
| ad ->
Queries.AD.to_mval ad
|> List.map ValueDomain.Addr.Mval.to_cil
in
let st' = forget_reachable man man.local deep_addrs in
let shallow_lvals = List.concat_map lvallist shallow_addrs in
List.fold_left (invalidate_one (Analyses.ask_of_man man) man) st' shallow_lvals


let special man r f args =
let ask = Analyses.ask_of_man man in
let st = man.local in
Expand Down Expand Up @@ -548,31 +577,7 @@ struct
assert_fn {man with local = st} (BinOp (Ge, Lval lv, zero, intType)) true
| None -> st)
| _, _ ->
let lvallist e =
match ask.f (Queries.MayPointTo e) with
| ad when Queries.AD.is_top ad -> []
| ad ->
Queries.AD.to_mval ad
|> List.map ValueDomain.Addr.Mval.to_cil
in
let shallow_addrs = LibraryDesc.Accesses.find desc.accs { kind = Write; deep = false } args in
let deep_addrs = LibraryDesc.Accesses.find desc.accs { kind = Write; deep = true } args in
let deep_addrs =
if List.mem LibraryDesc.InvalidateGlobals desc.attrs then (
foldGlobals !Cilfacade.current_file (fun acc global ->
match global with
| GVar (vi, _, _) when not (BaseUtil.is_static vi) ->
mkAddrOf (Var vi, NoOffset) :: acc
(* TODO: what about GVarDecl? *)
| _ -> acc
) deep_addrs
)
else
deep_addrs
in
let st' = forget_reachable man st deep_addrs in
let shallow_lvals = List.concat_map lvallist shallow_addrs in
let st' = List.fold_left (invalidate_one ask man) st' shallow_lvals in
let st' = special_unknown_invalidate man f args in
(* invalidate lval if present *)
match r with
| Some lv -> invalidate_one ask man st' lv
Expand Down Expand Up @@ -674,21 +679,19 @@ struct

let threadenter man ~multiple lval f args =
let st = man.local in
(* TODO: HACK: Simulate enter_multithreaded for first entering thread to publish global inits before analyzing thread.
Otherwise thread is analyzed with no global inits, reading globals gives bot, which turns into top, which might get published...
sync `Thread doesn't help us here, it's not specific to entering multithreaded mode.
EnterMultithreaded events only execute after threadenter and threadspawn. *)
if not (ThreadFlag.has_ever_been_multi (Analyses.ask_of_man man)) then
ignore (Priv.enter_multithreaded (Analyses.ask_of_man man) man.global man.sideg st);
Comment on lines +671 to +676
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Why is this moved out? Base only does it for non-unknown thread functions.

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The logic of why it is needed is the same here as it is for the case where a known thread is created: One should not go into multi-threaded mode without notifying the privatization that this switch happened to ensure everything that should be published is published.

Maybe base has some reason this can be avoided, but I'm not really sure why that should be the case. We may want to make an issue to investigate this.

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Also see the last few comments in #1551

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The one test in this PR doesn't cover this, does it?

I tried the very simple thing of creating a thread from unknown function pointer and that seems to work with base. That's because threadflag analysis emits the EnterMultiThreaded event which is handled by base (and relational).
The comment for this hack is about the globals values that get used when analyzing the created thread. For an unknown function pointer, there's no thread body to analyze anyway, so it's not clear to me when it would make a difference.

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The test covers it in some sense. We mean to invalidate e and output

[Info][Imprecise] Invalidating expressions: & e (1.c:11:3-11:35)

But this invalidation does not take and we still claim to be able to prove things about e.

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Edit: That case is listed in the linked issue.

match Cilfacade.find_varinfo_fundec f with
| fd ->
(* TODO: HACK: Simulate enter_multithreaded for first entering thread to publish global inits before analyzing thread.
Otherwise thread is analyzed with no global inits, reading globals gives bot, which turns into top, which might get published...
sync `Thread doesn't help us here, it's not specific to entering multithreaded mode.
EnterMultithreaded events only execute after threadenter and threadspawn. *)
if not (ThreadFlag.has_ever_been_multi (Analyses.ask_of_man man)) then
ignore (Priv.enter_multithreaded (Analyses.ask_of_man man) man.global man.sideg st);
let st' = Priv.threadenter (Analyses.ask_of_man man) man.global st in
let new_rel = make_callee_rel ~thread:true man fd args in
[{st' with rel = new_rel}]
| exception Not_found ->
(* Unknown functions *)
(* TODO: do something like base? *)
failwith "relation.threadenter: unknown function"
[special_unknown_invalidate man f args]

let threadspawn man ~multiple lval f args fman =
man.local
Expand Down
22 changes: 22 additions & 0 deletions tests/regression/46-apron2/98-invalidate-more.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,22 @@
// SKIP PARAM: --set ana.activated[+] apron --set sem.int.signed_overflow assume_none
#include <pthread.h>
#include <goblint.h>
#include <stdio.h>

int debug;
int other;

int main() {
int top;

// Needed so Base & DefExc doesn't find this information because it invalidates less
if(top) {
debug = 3;
}

fscanf(stdin, "%d", &other);

// Fails as debug is invalidated
__goblint_check(debug <= 3);
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return 0;
}
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