diff options
Diffstat (limited to 'library/core/tests/alloc.rs')
-rw-r--r-- | library/core/tests/alloc.rs | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/library/core/tests/alloc.rs b/library/core/tests/alloc.rs index 8a5a06b34..3ceaeadce 100644 --- a/library/core/tests/alloc.rs +++ b/library/core/tests/alloc.rs @@ -1,4 +1,5 @@ use core::alloc::Layout; +use core::mem::size_of; use core::ptr::{self, NonNull}; #[test] @@ -13,6 +14,49 @@ fn const_unchecked_layout() { } #[test] +fn layout_round_up_to_align_edge_cases() { + const MAX_SIZE: usize = isize::MAX as usize; + + for shift in 0..usize::BITS { + let align = 1_usize << shift; + let edge = (MAX_SIZE + 1) - align; + let low = edge.saturating_sub(10); + let high = edge.saturating_add(10); + assert!(Layout::from_size_align(low, align).is_ok()); + assert!(Layout::from_size_align(high, align).is_err()); + for size in low..=high { + assert_eq!( + Layout::from_size_align(size, align).is_ok(), + size.next_multiple_of(align) <= MAX_SIZE, + ); + } + } +} + +#[test] +fn layout_array_edge_cases() { + for_type::<i64>(); + for_type::<[i32; 0b10101]>(); + for_type::<[u8; 0b1010101]>(); + + // Make sure ZSTs don't lead to divide-by-zero + assert_eq!(Layout::array::<()>(usize::MAX).unwrap(), Layout::from_size_align(0, 1).unwrap()); + + fn for_type<T>() { + const MAX_SIZE: usize = isize::MAX as usize; + + let edge = (MAX_SIZE + 1) / size_of::<T>(); + let low = edge.saturating_sub(10); + let high = edge.saturating_add(10); + assert!(Layout::array::<T>(low).is_ok()); + assert!(Layout::array::<T>(high).is_err()); + for n in low..=high { + assert_eq!(Layout::array::<T>(n).is_ok(), n * size_of::<T>() <= MAX_SIZE); + } + } +} + +#[test] fn layout_debug_shows_log2_of_alignment() { // `Debug` is not stable, but here's what it does right now let layout = Layout::from_size_align(24576, 8192).unwrap(); |