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// run-pass
#![allow(dead_code)]
use std::mem;
// Raising alignment
#[repr(align(16))]
#[derive(Clone, Copy, Debug)]
struct Align16(i32);
// Lowering has no effect
#[repr(align(1))]
struct Align1(i32);
// Multiple attributes take the max
#[repr(align(4))]
#[repr(align(16))]
#[repr(align(8))]
struct AlignMany(i32);
// Raising alignment may not alter size.
#[repr(align(8))]
#[allow(dead_code)]
struct Align8Many {
a: i32,
b: i32,
c: i32,
d: u8,
}
enum Enum {
#[allow(dead_code)]
A(i32),
B(Align16)
}
// Nested alignment - use `#[repr(C)]` to suppress field reordering for sizeof test
#[repr(C)]
struct Nested {
a: i32,
b: i32,
c: Align16,
d: i8,
}
#[repr(packed)]
struct Packed(i32);
#[repr(align(16))]
struct AlignContainsPacked {
a: Packed,
b: Packed,
}
#[repr(C, packed(4))]
struct Packed4C {
a: u32,
b: u64,
}
#[repr(align(16))]
struct AlignContainsPacked4C {
a: Packed4C,
b: u64,
}
// The align limit was originally smaller (2^15).
// Check that it works with big numbers.
#[repr(align(0x10000))]
struct AlignLarge {
stuff: [u8; 0x10000],
}
union UnionContainsAlign {
a: Align16,
b: f32
}
impl Align16 {
// return aligned type
pub fn new(i: i32) -> Align16 {
Align16(i)
}
// pass aligned type
pub fn consume(a: Align16) -> i32 {
a.0
}
}
const CONST_ALIGN16: Align16 = Align16(7);
static STATIC_ALIGN16: Align16 = Align16(8);
// Check the actual address is aligned
fn is_aligned_to<T>(p: &T, align: usize) -> bool {
let addr = p as *const T as usize;
(addr & (align - 1)) == 0
}
pub fn main() {
// check alignment and size by type and value
assert_eq!(mem::align_of::<Align16>(), 16);
assert_eq!(mem::size_of::<Align16>(), 16);
let a = Align16(7);
assert_eq!(a.0, 7);
assert_eq!(mem::align_of_val(&a), 16);
assert_eq!(mem::size_of_val(&a), 16);
assert!(is_aligned_to(&a, 16));
// lowering should have no effect
assert_eq!(mem::align_of::<Align1>(), 4);
assert_eq!(mem::size_of::<Align1>(), 4);
let a = Align1(7);
assert_eq!(a.0, 7);
assert_eq!(mem::align_of_val(&a), 4);
assert_eq!(mem::size_of_val(&a), 4);
assert!(is_aligned_to(&a, 4));
// when multiple attributes are specified the max should be used
assert_eq!(mem::align_of::<AlignMany>(), 16);
assert_eq!(mem::size_of::<AlignMany>(), 16);
let a = AlignMany(7);
assert_eq!(a.0, 7);
assert_eq!(mem::align_of_val(&a), 16);
assert_eq!(mem::size_of_val(&a), 16);
assert!(is_aligned_to(&a, 16));
// raising alignment should not reduce size
assert_eq!(mem::align_of::<Align8Many>(), 8);
assert_eq!(mem::size_of::<Align8Many>(), 16);
let a = Align8Many { a: 1, b: 2, c: 3, d: 4 };
assert_eq!(a.a, 1);
assert_eq!(mem::align_of_val(&a), 8);
assert_eq!(mem::size_of_val(&a), 16);
assert!(is_aligned_to(&a, 8));
// return type
let a = Align16::new(1);
assert_eq!(mem::align_of_val(&a), 16);
assert_eq!(mem::size_of_val(&a), 16);
assert_eq!(a.0, 1);
assert!(is_aligned_to(&a, 16));
assert_eq!(Align16::consume(a), 1);
// check const alignment, size and value
assert_eq!(mem::align_of_val(&CONST_ALIGN16), 16);
assert_eq!(mem::size_of_val(&CONST_ALIGN16), 16);
assert_eq!(CONST_ALIGN16.0, 7);
assert!(is_aligned_to(&CONST_ALIGN16, 16));
// check global static alignment, size and value
assert_eq!(mem::align_of_val(&STATIC_ALIGN16), 16);
assert_eq!(mem::size_of_val(&STATIC_ALIGN16), 16);
assert_eq!(STATIC_ALIGN16.0, 8);
assert!(is_aligned_to(&STATIC_ALIGN16, 16));
// Note that the size of Nested may change if struct field re-ordering is enabled
assert_eq!(mem::align_of::<Nested>(), 16);
assert_eq!(mem::size_of::<Nested>(), 48);
let a = Nested{ a: 1, b: 2, c: Align16(3), d: 4};
assert_eq!(mem::align_of_val(&a), 16);
assert_eq!(mem::align_of_val(&a.b), 4);
assert_eq!(mem::align_of_val(&a.c), 16);
assert_eq!(mem::size_of_val(&a), 48);
assert!(is_aligned_to(&a, 16));
// check the correct fields are indexed
assert_eq!(a.a, 1);
assert_eq!(a.b, 2);
assert_eq!(a.c.0, 3);
assert_eq!(a.d, 4);
// enum should be aligned to max alignment
assert_eq!(mem::align_of::<Enum>(), 16);
assert_eq!(mem::align_of_val(&Enum::B(Align16(0))), 16);
let e = Enum::B(Align16(15));
match e {
Enum::B(ref a) => {
assert_eq!(a.0, 15);
assert_eq!(mem::align_of_val(a), 16);
assert_eq!(mem::size_of_val(a), 16);
},
_ => ()
}
assert!(is_aligned_to(&e, 16));
// check union alignment
assert_eq!(mem::align_of::<UnionContainsAlign>(), 16);
assert_eq!(mem::size_of::<UnionContainsAlign>(), 16);
let u = UnionContainsAlign { a: Align16(10) };
unsafe {
assert_eq!(mem::align_of_val(&u.a), 16);
assert_eq!(mem::size_of_val(&u.a), 16);
assert_eq!(u.a.0, 10);
let UnionContainsAlign { a } = u;
assert_eq!(a.0, 10);
}
// arrays of aligned elements should also be aligned
assert_eq!(mem::align_of::<[Align16;2]>(), 16);
assert_eq!(mem::size_of::<[Align16;2]>(), 32);
let a = [Align16(0), Align16(1)];
assert_eq!(mem::align_of_val(&a[0]), 16);
assert_eq!(mem::align_of_val(&a[1]), 16);
assert!(is_aligned_to(&a, 16));
// check heap value is aligned
assert_eq!(mem::align_of_val(Box::new(Align16(0)).as_ref()), 16);
// check heap array is aligned
let a = vec!(Align16(0), Align16(1));
assert_eq!(mem::align_of_val(&a[0]), 16);
assert_eq!(mem::align_of_val(&a[1]), 16);
assert_eq!(mem::align_of::<AlignContainsPacked>(), 16);
assert_eq!(mem::size_of::<AlignContainsPacked>(), 16);
let a = AlignContainsPacked { a: Packed(1), b: Packed(2) };
assert_eq!(mem::align_of_val(&a), 16);
assert_eq!(mem::align_of_val(&a.a), 1);
assert_eq!(mem::align_of_val(&a.b), 1);
assert_eq!(mem::size_of_val(&a), 16);
assert!(is_aligned_to(&a, 16));
assert_eq!(mem::align_of::<AlignContainsPacked4C>(), 16);
assert_eq!(mem::size_of::<AlignContainsPacked4C>(), 32);
let a = AlignContainsPacked4C { a: Packed4C{ a: 1, b: 2 }, b: 3 };
assert_eq!(mem::align_of_val(&a), 16);
assert_eq!(mem::align_of_val(&a.a), 4);
assert_eq!(mem::align_of_val(&a.b), mem::align_of::<u64>());
assert_eq!(mem::size_of_val(&a), 32);
assert!(is_aligned_to(&a, 16));
let mut large = Box::new(AlignLarge {
stuff: [0; 0x10000],
});
large.stuff[0] = 132;
*large.stuff.last_mut().unwrap() = 102;
assert_eq!(large.stuff[0], 132);
assert_eq!(large.stuff.last(), Some(&102));
assert_eq!(mem::align_of::<AlignLarge>(), 0x10000);
assert_eq!(mem::align_of_val(&*large), 0x10000);
assert!(is_aligned_to(&*large, 0x10000));
}
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