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Commit 43e1bd74 authored by David Bühler's avatar David Bühler
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Merge branch 'feature/eva/bitwise-small-sets-precision' into 'master' 

[ival] improve the precision of the computed small sets for bitwise operators

See merge request frama-c/frama-c!2736
parents 0935609f ff0b8e6d
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Inline Side-by-side
src/kernel_services/abstract_interp/int_set.ml
View file @ 43e1bd74
......@@ -318,7 +318,7 @@ let apply_bin_1_strict_decr f x (s : Integer.t array) =
in
c 0
let apply2_n f (s1 : Integer.t array) (s2 : Integer.t array) =
let apply2 f (s1 : Integer.t array) (s2 : Integer.t array) =
let ps = ref empty_ps in
let l1 = Array.length s1 in
let l2 = Array.length s2 in
......@@ -588,7 +588,7 @@ let add_singleton = apply_bin_1_strict_incr Int.add
let add s1 s2 =
match s1, s2 with
| [| x |], s | s, [| x |] -> `Set (apply_bin_1_strict_incr Int.add x s)
| _, _ -> apply2_n Int.add s1 s2
| _, _ -> apply2 Int.add s1 s2
let add_under s1 s2 =
match s1, s2 with
......@@ -619,7 +619,7 @@ let scale f s =
let mul s1 s2 =
match s1, s2 with
| s, [| x |] | [| x |], s -> `Set (scale x s)
| _, _ -> apply2_n Int.mul s1 s2
| _, _ -> apply2 Int.mul s1 s2
let scale_div ~pos f s =
assert (not (Int.is_zero f));
......
src/kernel_services/abstract_interp/int_set.mli
View file @ 43e1bd74
......@@ -97,6 +97,9 @@ type set_or_top =
type set_or_top_or_bottom = [ `Bottom | set_or_top ]
(** [apply2 f s1 s2] applies [f i1 i2] for all integers i1 in s1 and i2 in s2. *)
val apply2: (Integer.t -> Integer.t -> Integer.t) -> t -> t -> set_or_top
(** {2 Lattice structure.} *)
val is_included: t -> t -> bool
......
src/kernel_services/abstract_interp/int_val.ml
View file @ 43e1bd74
......@@ -660,6 +660,8 @@ end
module type BitOperator =
sig
(* Concrete version of the bitwise operator *)
val concrete_bitwise : Int.t -> Int.t -> Int.t
(* Printable version of the operator *)
val representation : string
(* forward is given here as the lifted function of some bit operator op
......@@ -682,6 +684,8 @@ end
module And : BitOperator =
struct
let concrete_bitwise = Int.logand
let representation = "&"
let forward v1 v2 =
......@@ -701,6 +705,8 @@ end
module Or : BitOperator =
struct
let concrete_bitwise = Int.logor
let representation = "|"
let forward v1 v2 =
......@@ -720,6 +726,8 @@ end
module Xor : BitOperator =
struct
let concrete_bitwise = Int.logxor
let representation = "^"
let forward v1 v2 =
......@@ -893,7 +901,15 @@ struct
acc := List.fold_left (set_bit (Bit i)) [] !acc;
if List.length !acc > small_cardinal () then raise Do_not_fit_small_sets
done;
let list = List.map (fun (r, _, _) -> r) !acc in
(* Keep only values that can actually be obtained *)
let is_admissible (r, v1, v2) =
match v1, v2 with
| Set s1, Set s2 ->
let op = Op.concrete_bitwise in
Int_set.(exists (fun i1 -> exists (fun i2 -> op i1 i2 = r) s2) s1)
| _, _ -> true
in
let list = Extlib.filter_map is_admissible (fun (r, _, _) -> r) !acc in
Set (Int_set.inject_list list)
(* If lower is true (resp. false), compute the lower (resp. upper) bound of
......@@ -936,18 +952,22 @@ struct
bound
let bitwise_forward (v1 : t) (v2 : t) : t =
let r, modu = compute_modulo v1 v2 in
match result_size v1 v2 with
| None ->
(* We could do better here, as one of the bound may be finite. However,
this case should occur rarely or not at all. *)
inject_interval None None r modu
| Some size ->
try compute_small_set ~size v1 v2 r modu
with Do_not_fit_small_sets ->
let min = compute_bound ~size v1 v2 true
and max = compute_bound ~size v1 v2 false in
inject_interval (Some min) (Some max) r modu
match v1, v2 with
| Set s1, Set s2 ->
inject_set_or_top (Int_set.apply2 Op.concrete_bitwise s1 s2)
| _, _ ->
let r, modu = compute_modulo v1 v2 in
match result_size v1 v2 with
| None ->
(* We could do better here, as one of the bound may be finite. However,
this case should occur rarely or not at all. *)
inject_interval None None r modu
| Some size ->
try compute_small_set ~size v1 v2 r modu
with Do_not_fit_small_sets ->
let min = compute_bound ~size v1 v2 true
and max = compute_bound ~size v1 v2 false in
inject_interval (Some min) (Some max) r modu
end
let bitwise_or = let module M = BitwiseOperator (Or) in M.bitwise_forward
......
tests/value/bitwise.i
View file @ 43e1bd74
......@@ -2,11 +2,16 @@
STDOPT: +"-big-ints-hex 256"
*/
/*@ assigns \result \from min, max;
ensures min <= \result <= max ;
/*@ assigns \result \from a, b;
ensures result_a_or_b: \result == a || \result == b ;
*/
int Frama_C_interval(int min, int max);
extern int Frama_C_nondet(int a, int b);
/*@ requires order: min <= max;
assigns \result \from min, max;
ensures result_bounded: min <= \result <= max ;
*/
extern int Frama_C_interval(int min, int max);
volatile long v;
volatile unsigned char input[3];
......@@ -67,13 +72,22 @@ int test4(void)
if (something & 0x80000000) {
Frama_C_show_each_true(something);
return 0;
}
}
else {
Frama_C_show_each_false(something);
return 1;
}
}
void test5(void)
{
int x = Frama_C_nondet(-1, 0);
int y = Frama_C_nondet(-1, 0);
int a = x & y;
int b = x | y;
int c = x ^ y;
}
void and_or_rel(void)
{
long x, r1, r2, r3;
......@@ -150,6 +164,7 @@ void main(void) {
test2();
test3();
test4();
test5();
and_or_rel();
double_neg();
bug1();
......
tests/value/oracle/bitwise.res.oracle
View file @ 43e1bd74
......@@ -7,76 +7,95 @@
input[0..2] ∈ [--..--]
s ∈ [--..--]
[eva] computing for function test1 <- main.
Called from tests/value/bitwise.i:149.
Called from tests/value/bitwise.i:163.
[eva] computing for function Frama_C_interval <- test1 <- main.
Called from tests/value/bitwise.i:23.
Called from tests/value/bitwise.i:28.
[eva] using specification for function Frama_C_interval
[eva] tests/value/bitwise.i:28:
function Frama_C_interval: precondition 'order' got status valid.
[eva] Done for function Frama_C_interval
[eva] computing for function Frama_C_interval <- test1 <- main.
Called from tests/value/bitwise.i:24.
Called from tests/value/bitwise.i:29.
[eva] tests/value/bitwise.i:29:
function Frama_C_interval: precondition 'order' got status valid.
[eva] Done for function Frama_C_interval
[eva] computing for function Frama_C_interval <- test1 <- main.
Called from tests/value/bitwise.i:25.
Called from tests/value/bitwise.i:30.
[eva] tests/value/bitwise.i:30:
function Frama_C_interval: precondition 'order' got status valid.
[eva] Done for function Frama_C_interval
[eva] Recording results for test1
[eva] Done for function test1
[eva] computing for function test2 <- main.
Called from tests/value/bitwise.i:150.
Called from tests/value/bitwise.i:164.
[eva] computing for function Frama_C_interval <- test2 <- main.
Called from tests/value/bitwise.i:50.
Called from tests/value/bitwise.i:55.
[eva] tests/value/bitwise.i:55:
function Frama_C_interval: precondition 'order' got status valid.
[eva] Done for function Frama_C_interval
[eva] Recording results for test2
[eva] Done for function test2
[eva] computing for function test3 <- main.
Called from tests/value/bitwise.i:151.
Called from tests/value/bitwise.i:165.
[eva] Recording results for test3
[eva] Done for function test3
[eva] computing for function test4 <- main.
Called from tests/value/bitwise.i:152.
[eva] tests/value/bitwise.i:62: assertion got status valid.
[eva] tests/value/bitwise.i:64:
Called from tests/value/bitwise.i:166.
[eva] tests/value/bitwise.i:67: assertion got status valid.
[eva] tests/value/bitwise.i:69:
Frama_C_show_each_1: [0x80000000..0xFFFFFFFF], {0x80000000}
[eva] tests/value/bitwise.i:64: Frama_C_show_each_1: [0..0x7FFFFFFF], {0}
[eva] tests/value/bitwise.i:66:
[eva] tests/value/bitwise.i:69: Frama_C_show_each_1: [0..0x7FFFFFFF], {0}
[eva] tests/value/bitwise.i:71:
Frama_C_show_each_2: [0..0x7FFFFFFF], {0}, {0x80000000}
[eva] tests/value/bitwise.i:66: Frama_C_show_each_2: [0..0x7FFFFFFF], {0}, {0}
[eva] tests/value/bitwise.i:72: Frama_C_show_each_false: [0..0x7FFFFFFF]
[eva] tests/value/bitwise.i:72: Frama_C_show_each_false: [0..0x7FFFFFFF]
[eva] tests/value/bitwise.i:71: Frama_C_show_each_2: [0..0x7FFFFFFF], {0}, {0}
[eva] tests/value/bitwise.i:77: Frama_C_show_each_false: [0..0x7FFFFFFF]
[eva] tests/value/bitwise.i:77: Frama_C_show_each_false: [0..0x7FFFFFFF]
[eva] Recording results for test4
[eva] Done for function test4
[eva] computing for function test5 <- main.
Called from tests/value/bitwise.i:167.
[eva] computing for function Frama_C_nondet <- test5 <- main.
Called from tests/value/bitwise.i:84.
[eva] using specification for function Frama_C_nondet
[eva] Done for function Frama_C_nondet
[eva] computing for function Frama_C_nondet <- test5 <- main.
Called from tests/value/bitwise.i:85.
[eva] Done for function Frama_C_nondet
[eva] Recording results for test5
[eva] Done for function test5
[eva] computing for function and_or_rel <- main.
Called from tests/value/bitwise.i:153.
[eva:alarm] tests/value/bitwise.i:87: Warning: assertion got status unknown.
Called from tests/value/bitwise.i:168.
[eva:alarm] tests/value/bitwise.i:101: Warning: assertion got status unknown.
[eva] Recording results for and_or_rel
[eva] Done for function and_or_rel
[eva] computing for function double_neg <- main.
Called from tests/value/bitwise.i:154.
Called from tests/value/bitwise.i:169.
[eva] Recording results for double_neg
[eva] Done for function double_neg
[eva] computing for function bug1 <- main.
Called from tests/value/bitwise.i:155.
Called from tests/value/bitwise.i:170.
[eva] Recording results for bug1
[eva] Done for function bug1
[eva] computing for function bug2 <- main.
Called from tests/value/bitwise.i:156.
[eva] tests/value/bitwise.i:114: Frama_C_show_each_then:
[eva] tests/value/bitwise.i:114: Frama_C_show_each_else:
Called from tests/value/bitwise.i:171.
[eva] tests/value/bitwise.i:128: Frama_C_show_each_then:
[eva] tests/value/bitwise.i:128: Frama_C_show_each_else:
[eva] Recording results for bug2
[eva] Done for function bug2
[eva] computing for function bug3 <- main.
Called from tests/value/bitwise.i:157.
[eva] tests/value/bitwise.i:121: Frama_C_show_each: {0x41F656F}, {0xFBE09A91}
Called from tests/value/bitwise.i:172.
[eva] tests/value/bitwise.i:135: Frama_C_show_each: {0x41F656F}, {0xFBE09A91}
[eva] Recording results for bug3
[eva] Done for function bug3
[eva] computing for function bug4 <- main.
Called from tests/value/bitwise.i:158.
[eva] tests/value/bitwise.i:131: Frama_C_show_each_then:
[eva] tests/value/bitwise.i:133: Frama_C_show_each_else:
Called from tests/value/bitwise.i:173.
[eva] tests/value/bitwise.i:145: Frama_C_show_each_then:
[eva] tests/value/bitwise.i:147: Frama_C_show_each_else:
[eva] Recording results for bug4
[eva] Done for function bug4
[eva] computing for function bug5 <- main.
Called from tests/value/bitwise.i:159.
[eva] tests/value/bitwise.i:144: Frama_C_show_each_dead: {0}
Called from tests/value/bitwise.i:174.
[eva] tests/value/bitwise.i:158: Frama_C_show_each_dead: {0}
[eva] Recording results for bug5
[eva] Done for function bug5
[eva] Recording results for main
......@@ -136,6 +155,12 @@
something ∈ [0..0x7FFFFFFF]
topBitOnly ∈ {0; 0x80000000}
__retres ∈ {1}
[eva:final-states] Values at end of function test5:
x ∈ {-1; 0}
y ∈ {-1; 0}
a ∈ {-1; 0}
b ∈ {-1; 0}
c ∈ {-1; 0}
[eva:final-states] Values at end of function main:
[from] Computing for function and_or_rel
......@@ -162,12 +187,18 @@
[from] Done for function test3
[from] Computing for function test4
[from] Done for function test4
[from] Computing for function test5
[from] Computing for function Frama_C_nondet <-test5
[from] Done for function Frama_C_nondet
[from] Done for function test5
[from] Computing for function main
[from] Done for function main
[from] ====== DEPENDENCIES COMPUTED ======
These dependencies hold at termination for the executions that terminate:
[from] Function Frama_C_interval:
\result FROM min; max
[from] Function Frama_C_nondet:
\result FROM a; b
[from] Function and_or_rel:
NO EFFECTS
[from] Function bug1:
......@@ -190,6 +221,8 @@
NO EFFECTS
[from] Function test4:
\result FROM v
[from] Function test5:
NO EFFECTS
[from] Function main:
NO EFFECTS
[from] ====== END OF DEPENDENCIES ======
......@@ -238,6 +271,10 @@
something; topBitOnly; __retres
[inout] Inputs for function test4:
v
[inout] Out (internal) for function test5:
x; y; a; b; c
[inout] Inputs for function test5:
\nothing
[inout] Out (internal) for function main:
\nothing
[inout] Inputs for function main:
......
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