104 lines
3.2 KiB
Rust
104 lines
3.2 KiB
Rust
// compile-flags: -Zmiri-symbolic-alignment-check
|
|
|
|
fn test_align_offset() {
|
|
let d = Box::new([0u32; 4]);
|
|
// Get u8 pointer to base
|
|
let raw = d.as_ptr() as *const u8;
|
|
|
|
assert_eq!(raw.align_offset(2), 0);
|
|
assert_eq!(raw.align_offset(4), 0);
|
|
assert_eq!(raw.align_offset(8), usize::MAX); // requested alignment higher than allocation alignment
|
|
|
|
assert_eq!(raw.wrapping_offset(1).align_offset(2), 1);
|
|
assert_eq!(raw.wrapping_offset(1).align_offset(4), 3);
|
|
assert_eq!(raw.wrapping_offset(1).align_offset(8), usize::MAX); // requested alignment higher than allocation alignment
|
|
|
|
assert_eq!(raw.wrapping_offset(2).align_offset(2), 0);
|
|
assert_eq!(raw.wrapping_offset(2).align_offset(4), 2);
|
|
assert_eq!(raw.wrapping_offset(2).align_offset(8), usize::MAX); // requested alignment higher than allocation alignment
|
|
}
|
|
|
|
fn test_align_to() {
|
|
const N: usize = 4;
|
|
let d = Box::new([0u32; N]);
|
|
// Get u8 slice covering the entire thing
|
|
let s = unsafe { std::slice::from_raw_parts(d.as_ptr() as *const u8, 4 * N) };
|
|
let raw = s.as_ptr();
|
|
|
|
{
|
|
let (l, m, r) = unsafe { s.align_to::<u32>() };
|
|
assert_eq!(l.len(), 0);
|
|
assert_eq!(r.len(), 0);
|
|
assert_eq!(m.len(), N);
|
|
assert_eq!(raw, m.as_ptr() as *const u8);
|
|
}
|
|
|
|
{
|
|
let (l, m, r) = unsafe { s[1..].align_to::<u32>() };
|
|
assert_eq!(l.len(), 3);
|
|
assert_eq!(m.len(), N-1);
|
|
assert_eq!(r.len(), 0);
|
|
assert_eq!(raw.wrapping_offset(4), m.as_ptr() as *const u8);
|
|
}
|
|
|
|
{
|
|
let (l, m, r) = unsafe { s[..4*N - 1].align_to::<u32>() };
|
|
assert_eq!(l.len(), 0);
|
|
assert_eq!(m.len(), N-1);
|
|
assert_eq!(r.len(), 3);
|
|
assert_eq!(raw, m.as_ptr() as *const u8);
|
|
}
|
|
|
|
{
|
|
let (l, m, r) = unsafe { s[1..4*N - 1].align_to::<u32>() };
|
|
assert_eq!(l.len(), 3);
|
|
assert_eq!(m.len(), N-2);
|
|
assert_eq!(r.len(), 3);
|
|
assert_eq!(raw.wrapping_offset(4), m.as_ptr() as *const u8);
|
|
}
|
|
|
|
{
|
|
#[repr(align(8))] struct Align8(u64);
|
|
let (l, m, r) = unsafe { s.align_to::<Align8>() }; // requested alignment higher than allocation alignment
|
|
assert_eq!(l.len(), 4*N);
|
|
assert_eq!(r.len(), 0);
|
|
assert_eq!(m.len(), 0);
|
|
}
|
|
}
|
|
|
|
fn test_from_utf8() {
|
|
const N: usize = 10;
|
|
let vec = vec![0x4141414141414141u64; N];
|
|
let content = unsafe { std::slice::from_raw_parts(vec.as_ptr() as *const u8, 8 * N) };
|
|
println!("{:?}", std::str::from_utf8(content).unwrap());
|
|
}
|
|
|
|
fn test_u64_array() {
|
|
#[derive(Default)]
|
|
#[repr(align(8))]
|
|
struct AlignToU64<T>(T);
|
|
|
|
const BYTE_LEN: usize = std::mem::size_of::<[u64; 4]>();
|
|
type Data = AlignToU64<[u8; BYTE_LEN]>;
|
|
|
|
fn example(data: &Data) {
|
|
let (head, u64_arrays, tail) = unsafe { data.0.align_to::<[u64; 4]>() };
|
|
|
|
assert!(head.is_empty(), "buffer was not aligned for 64-bit numbers");
|
|
assert_eq!(u64_arrays.len(), 1, "buffer was not long enough");
|
|
assert!(tail.is_empty(), "buffer was too long");
|
|
|
|
let u64_array = &u64_arrays[0];
|
|
let _val = u64_array[0]; // make sure we can actually load this
|
|
}
|
|
|
|
example(&Data::default());
|
|
}
|
|
|
|
fn main() {
|
|
test_align_offset();
|
|
test_align_to();
|
|
test_from_utf8();
|
|
test_u64_array();
|
|
}
|