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| 1 | +//@ run-pass |
| 2 | +//@ reference: layout.aggregate.struct-offsets |
| 3 | +//@ edition: 2018 |
| 4 | + |
| 5 | +#[repr(align(64))] |
| 6 | +#[derive(Copy, Clone)] |
| 7 | +#[allow(dead_code)] |
| 8 | +pub struct Overaligned(u8); |
| 9 | + |
| 10 | +#[allow(dead_code)] |
| 11 | +struct ReprRustStruct { |
| 12 | + x: i32, |
| 13 | + y: [u32; 4], |
| 14 | + z: f32, |
| 15 | + a: u128, |
| 16 | + b: Overaligned, |
| 17 | +} |
| 18 | + |
| 19 | +macro_rules! span_of { |
| 20 | + ($ty:ty , $field:tt) => {{ |
| 21 | + let __field = unsafe { ::core::mem::zeroed::<$ty>() }; |
| 22 | + |
| 23 | + ( |
| 24 | + core::mem::offset_of!($ty, $field), |
| 25 | + core::mem::offset_of!($ty, $field) + core::mem::size_of_val(&__field.$field), |
| 26 | + ) |
| 27 | + }}; |
| 28 | +} |
| 29 | + |
| 30 | +fn test_fields_make_sense(a: &(usize, usize)) { |
| 31 | + assert!(a.0 <= a.1); |
| 32 | +} |
| 33 | + |
| 34 | +// order is `begin, end` |
| 35 | +fn test_non_overlapping(a: &(usize, usize), b: &(usize, usize)) { |
| 36 | + assert!((a.1 <= b.0) || (b.1 <= a.0)); |
| 37 | +} |
| 38 | + |
| 39 | +fn test_fields_non_overlapping() { |
| 40 | + let fields = [ |
| 41 | + span_of!(ReprRustStruct, x), |
| 42 | + span_of!(ReprRustStruct, y), |
| 43 | + span_of!(ReprRustStruct, z), |
| 44 | + span_of!(ReprRustStruct, a), |
| 45 | + span_of!(ReprRustStruct, b), |
| 46 | + ]; |
| 47 | + |
| 48 | + test_fields_make_sense(&fields[0]); |
| 49 | + test_fields_make_sense(&fields[1]); |
| 50 | + test_fields_make_sense(&fields[2]); |
| 51 | + test_fields_make_sense(&fields[3]); |
| 52 | + test_fields_make_sense(&fields[4]); |
| 53 | + |
| 54 | + test_non_overlapping(&fields[0], &fields[1]); |
| 55 | + test_non_overlapping(&fields[0], &fields[2]); |
| 56 | + test_non_overlapping(&fields[0], &fields[3]); |
| 57 | + test_non_overlapping(&fields[0], &fields[4]); |
| 58 | + test_non_overlapping(&fields[1], &fields[2]); |
| 59 | + test_non_overlapping(&fields[2], &fields[3]); |
| 60 | + test_non_overlapping(&fields[2], &fields[4]); |
| 61 | + test_non_overlapping(&fields[3], &fields[4]); |
| 62 | +} |
| 63 | + |
| 64 | +fn test_fields_aligned() { |
| 65 | + assert_eq!((core::mem::offset_of!(ReprRustStruct, x) % (core::mem::align_of::<i32>())), 0); |
| 66 | + assert_eq!((core::mem::offset_of!(ReprRustStruct, y) % (core::mem::align_of::<[u32; 4]>())), 0); |
| 67 | + assert_eq!((core::mem::offset_of!(ReprRustStruct, z) % (core::mem::align_of::<f32>())), 0); |
| 68 | + assert_eq!((core::mem::offset_of!(ReprRustStruct, a) % (core::mem::align_of::<u128>())), 0); |
| 69 | + assert_eq!( |
| 70 | + (core::mem::offset_of!(ReprRustStruct, b) % (core::mem::align_of::<Overaligned>())), |
| 71 | + 0 |
| 72 | + ); |
| 73 | +} |
| 74 | + |
| 75 | +fn main() { |
| 76 | + test_fields_non_overlapping(); |
| 77 | + test_fields_aligned(); |
| 78 | +} |
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