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
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
//! Implements methods to write a vector type to a slice.
macro_rules! impl_slice_write_to_slice {
([$elem_ty:ident; $elem_count:expr]: $id:ident | $test_tt:tt) => {
impl $id {
/// Writes the values of the vector to the `slice`.
///
/// # Panics
///
/// If `slice.len() < Self::lanes()` or `&slice[0]` is not
/// aligned to an `align_of::<Self>()` boundary.
#[inline]
pub fn write_to_slice_aligned(self, slice: &mut [$elem_ty]) {
unsafe {
assert!(slice.len() >= $elem_count);
let target_ptr =
slice.get_unchecked_mut(0) as *mut $elem_ty;
assert_eq!(
target_ptr.align_offset(crate::mem::align_of::<Self>()),
0
);
self.write_to_slice_aligned_unchecked(slice);
}
}
/// Writes the values of the vector to the `slice`.
///
/// # Panics
///
/// If `slice.len() < Self::lanes()`.
#[inline]
pub fn write_to_slice_unaligned(self, slice: &mut [$elem_ty]) {
unsafe {
assert!(slice.len() >= $elem_count);
self.write_to_slice_unaligned_unchecked(slice);
}
}
/// Writes the values of the vector to the `slice`.
///
/// # Precondition
///
/// If `slice.len() < Self::lanes()` or `&slice[0]` is not
/// aligned to an `align_of::<Self>()` boundary, the behavior is
/// undefined.
#[inline]
pub unsafe fn write_to_slice_aligned_unchecked(
self, slice: &mut [$elem_ty],
) {
debug_assert!(slice.len() >= $elem_count);
let target_ptr =
slice.get_unchecked_mut(0) as *mut $elem_ty;
debug_assert_eq!(
target_ptr.align_offset(crate::mem::align_of::<Self>()),
0
);
#[cfg_attr(feature = "cargo-clippy", allow(clippy::cast_ptr_alignment))]
*(target_ptr as *mut Self) = self;
}
/// Writes the values of the vector to the `slice`.
///
/// # Precondition
///
/// If `slice.len() < Self::lanes()` the behavior is undefined.
#[inline]
pub unsafe fn write_to_slice_unaligned_unchecked(
self, slice: &mut [$elem_ty],
) {
debug_assert!(slice.len() >= $elem_count);
let target_ptr =
slice.get_unchecked_mut(0) as *mut $elem_ty as *mut u8;
let self_ptr = &self as *const Self as *const u8;
crate::ptr::copy_nonoverlapping(
self_ptr,
target_ptr,
crate::mem::size_of::<Self>(),
);
}
}
test_if!{
$test_tt:
paste::item! {
pub mod [<$id _slice_write_to_slice>] {
use super::*;
use crate::iter::Iterator;
#[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
fn write_to_slice_unaligned() {
let mut unaligned = [0 as $elem_ty; $id::lanes() + 1];
let vec = $id::splat(42 as $elem_ty);
vec.write_to_slice_unaligned(&mut unaligned[1..]);
for (index, &b) in unaligned.iter().enumerate() {
if index == 0 {
assert_eq!(b, 0 as $elem_ty);
} else {
assert_eq!(b, 42 as $elem_ty);
assert_eq!(b, vec.extract(index - 1));
}
}
}
// FIXME: wasm-bindgen-test does not support #[should_panic]
// #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
#[cfg(not(target_arch = "wasm32"))]
#[test]
#[should_panic]
fn write_to_slice_unaligned_fail() {
let mut unaligned = [0 as $elem_ty; $id::lanes() + 1];
let vec = $id::splat(42 as $elem_ty);
vec.write_to_slice_unaligned(&mut unaligned[2..]);
}
union A {
data: [$elem_ty; 2 * $id::lanes()],
_vec: $id,
}
#[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
fn write_to_slice_aligned() {
let mut aligned = A {
data: [0 as $elem_ty; 2 * $id::lanes()],
};
let vec = $id::splat(42 as $elem_ty);
unsafe { vec.write_to_slice_aligned(&mut aligned.data[$id::lanes()..]) };
for (index, &b) in unsafe { aligned.data.iter().enumerate() } {
if index < $id::lanes() {
assert_eq!(b, 0 as $elem_ty);
} else {
assert_eq!(b, 42 as $elem_ty);
assert_eq!(b, vec.extract(index - $id::lanes()));
}
}
}
// FIXME: wasm-bindgen-test does not support #[should_panic]
// #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
#[cfg(not(target_arch = "wasm32"))]
#[test]
#[should_panic]
fn write_to_slice_aligned_fail_lanes() {
let mut aligned = A {
data: [0 as $elem_ty; 2 * $id::lanes()],
};
let vec = $id::splat(42 as $elem_ty);
unsafe {
vec.write_to_slice_aligned(&mut aligned.data[2 * $id::lanes()..])
};
}
// FIXME: wasm-bindgen-test does not support #[should_panic]
// #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
#[cfg(not(target_arch = "wasm32"))]
#[test]
#[should_panic]
fn write_to_slice_aligned_fail_align() {
unsafe {
let mut aligned = A {
data: [0 as $elem_ty; 2 * $id::lanes()],
};
// get a pointer to the front of data
let ptr: *mut $elem_ty = aligned.data.as_mut_ptr() as *mut $elem_ty;
// offset pointer by one element
let ptr = ptr.wrapping_add(1);
if ptr.align_offset(crate::mem::align_of::<$id>()) == 0 {
// the pointer is properly aligned, so write_to_slice_aligned
// won't fail here (e.g. this can happen for i128x1). So
// we panic to make the "should_fail" test pass:
panic!("ok");
}
// create a slice - this is safe, because the elements
// of the slice exist, are properly initialized, and properly aligned:
let s: &mut [$elem_ty] = slice::from_raw_parts_mut(ptr, $id::lanes());
// this should always panic because the slice alignment does not match
// the alignment requirements for the vector type:
let vec = $id::splat(42 as $elem_ty);
vec.write_to_slice_aligned(s);
}
}
}
}
}
};
}