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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
use super::*;
// The tests below compare the computed hashes to particular expected values
// in order to test that we produce the same results on different platforms,
// regardless of endianness and `usize` and `isize` size differences (this
// of course assumes we run these tests on platforms that differ in those
// ways). The expected values depend on the hashing algorithm used, so they
// need to be updated whenever StableHasher changes its hashing algorithm.
#[test]
fn test_hash_integers() {
// Test that integers are handled consistently across platforms.
let test_u8 = 0xAB_u8;
let test_u16 = 0xFFEE_u16;
let test_u32 = 0x445577AA_u32;
let test_u64 = 0x01234567_13243546_u64;
let test_u128 = 0x22114433_66557788_99AACCBB_EEDDFF77_u128;
let test_usize = 0xD0C0B0A0_usize;
let test_i8 = -100_i8;
let test_i16 = -200_i16;
let test_i32 = -300_i32;
let test_i64 = -400_i64;
let test_i128 = -500_i128;
let test_isize = -600_isize;
let mut h = StableHasher::new();
test_u8.hash(&mut h);
test_u16.hash(&mut h);
test_u32.hash(&mut h);
test_u64.hash(&mut h);
test_u128.hash(&mut h);
test_usize.hash(&mut h);
test_i8.hash(&mut h);
test_i16.hash(&mut h);
test_i32.hash(&mut h);
test_i64.hash(&mut h);
test_i128.hash(&mut h);
test_isize.hash(&mut h);
// This depends on the hashing algorithm. See note at top of file.
let expected = (1784307454142909076, 11471672289340283879);
assert_eq!(h.finalize(), expected);
}
#[test]
fn test_hash_usize() {
// Test that usize specifically is handled consistently across platforms.
let test_usize = 0xABCDEF01_usize;
let mut h = StableHasher::new();
test_usize.hash(&mut h);
// This depends on the hashing algorithm. See note at top of file.
let expected = (5798740672699530587, 11186240177685111648);
assert_eq!(h.finalize(), expected);
}
#[test]
fn test_hash_isize() {
// Test that isize specifically is handled consistently across platforms.
let test_isize = -7_isize;
let mut h = StableHasher::new();
test_isize.hash(&mut h);
// This depends on the hashing algorithm. See note at top of file.
let expected = (2789913510339652884, 674280939192711005);
assert_eq!(h.finalize(), expected);
}
fn hash<T: HashStable<()>>(t: &T) -> u128 {
let mut h = StableHasher::new();
let ctx = &mut ();
t.hash_stable(ctx, &mut h);
h.finish()
}
// Check that bit set hash includes the domain size.
#[test]
fn test_hash_bit_set() {
use rustc_index::bit_set::BitSet;
let a: BitSet<usize> = BitSet::new_empty(1);
let b: BitSet<usize> = BitSet::new_empty(2);
assert_ne!(a, b);
assert_ne!(hash(&a), hash(&b));
}
// Check that bit matrix hash includes the matrix dimensions.
#[test]
fn test_hash_bit_matrix() {
use rustc_index::bit_set::BitMatrix;
let a: BitMatrix<usize, usize> = BitMatrix::new(1, 1);
let b: BitMatrix<usize, usize> = BitMatrix::new(1, 2);
assert_ne!(a, b);
assert_ne!(hash(&a), hash(&b));
}
// Check that exchanging the value of two adjacent fields changes the hash.
#[test]
fn test_attribute_permutation() {
macro_rules! test_type {
($ty: ty) => {{
struct Foo {
a: $ty,
b: $ty,
}
impl<CTX> HashStable<CTX> for Foo {
fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
self.a.hash_stable(hcx, hasher);
self.b.hash_stable(hcx, hasher);
}
}
#[allow(overflowing_literals)]
let mut item = Foo { a: 0xFF, b: 0xFF_FF };
let hash_a = hash(&item);
std::mem::swap(&mut item.a, &mut item.b);
let hash_b = hash(&item);
assert_ne!(
hash_a,
hash_b,
"The hash stayed the same after values were swapped for type `{}`!",
stringify!($ty)
);
}};
}
test_type!(u16);
test_type!(u32);
test_type!(u64);
test_type!(u128);
test_type!(i16);
test_type!(i32);
test_type!(i64);
test_type!(i128);
}
// Check that the `isize` hashing optimization does not produce the same hash when permuting two
// values.
#[test]
fn test_isize_compression() {
fn check_hash(a: u64, b: u64) {
let hash_a = hash(&(a as isize, b as isize));
let hash_b = hash(&(b as isize, a as isize));
assert_ne!(
hash_a, hash_b,
"The hash stayed the same when permuting values `{a}` and `{b}`!",
);
}
check_hash(0xAA, 0xAAAA);
check_hash(0xFF, 0xFFFF);
check_hash(0xAAAA, 0xAAAAAA);
check_hash(0xAAAAAA, 0xAAAAAAAA);
check_hash(0xFF, 0xFFFFFFFFFFFFFFFF);
check_hash(u64::MAX /* -1 */, 1);
}
|
