1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
var GlobalFlag: bool;
const A: int;
const B: int;
const C: int;
procedure Join(b: bool);
modifies GlobalFlag;
implementation Join(b: bool)
{
var x: int;
var y: int;
var z: int;
start:
assume {:inferred} true;
GlobalFlag := true;
x := 3;
y := 4;
z := x + y;
assume {:inferred} GlobalFlag && x == 3 && y == 4 && z == 7;
goto Then, Else;
Else:
assume {:inferred} GlobalFlag && x == 3 && y == 4 && z == 7;
assume b <==> false;
y := 4;
assume {:inferred} GlobalFlag && x == 3 && y == 4 && z == 7 && !b;
goto join;
join:
assume {:inferred} GlobalFlag && 3 <= x && x < 5 && y == 4 && z == 7;
assert y == 4;
assert z == 7;
assert GlobalFlag <==> true;
assume {:inferred} GlobalFlag && 3 <= x && x < 5 && y == 4 && z == 7;
return;
Then:
assume {:inferred} GlobalFlag && x == 3 && y == 4 && z == 7;
assume b <==> true;
x := x + 1;
assume {:inferred} GlobalFlag && x == 4 && y == 4 && z == 7 && b;
goto join;
}
procedure Loop();
implementation Loop()
{
var c: int;
var i: int;
start:
assume {:inferred} true;
c := 0;
i := 0;
assume {:inferred} c == 0 && i == 0;
goto test;
test: // cut point
assume {:inferred} c == 0 && 0 <= i && i < 11;
assume {:inferred} c == 0 && 0 <= i && i < 11;
goto Then, Else;
Else:
assume {:inferred} c == 0 && 0 <= i && i < 11;
assume {:inferred} c == 0 && 0 <= i && i < 11;
return;
Then:
assume {:inferred} c == 0 && 0 <= i && i < 11;
assume i < 10;
i := i + 1;
assume {:inferred} c == 0 && 1 <= i && i < 11;
goto test;
}
procedure Evaluate();
implementation Evaluate()
{
var i: int;
start:
assume {:inferred} true;
i := 5;
i := 3 * i + 1;
i := 3 * (i + 1);
i := 1 + 3 * i;
i := (i + 1) * 3;
assume {:inferred} i == 465;
return;
}
Boogie program verifier finished with 0 verified, 0 errors
Intervals.bpl(62,3): Error BP5001: This assertion might not hold.
Execution trace:
Intervals.bpl(57,5): anon0
Intervals.bpl(58,3): anon3_LoopHead
Intervals.bpl(58,3): anon3_LoopDone
Intervals.bpl(73,3): Error BP5001: This assertion might not hold.
Execution trace:
Intervals.bpl(68,5): anon0
Intervals.bpl(69,3): anon3_LoopHead
Intervals.bpl(69,3): anon3_LoopDone
Intervals.bpl(92,3): Error BP5001: This assertion might not hold.
Execution trace:
Intervals.bpl(87,5): anon0
Intervals.bpl(88,3): loop_head
Intervals.bpl(91,3): after_loop
Boogie program verifier finished with 5 verified, 3 errors
|
