1 use core::alloc::Layout;
2 use core::ptr::NonNull;
5 fn const_unchecked_layout() {
6 const SIZE: usize = 0x2000;
7 const ALIGN: usize = 0x1000;
8 const LAYOUT: Layout = unsafe { Layout::from_size_align_unchecked(SIZE, ALIGN) };
9 const DANGLING: NonNull<u8> = LAYOUT.dangling();
10 assert_eq!(LAYOUT.size(), SIZE);
11 assert_eq!(LAYOUT.align(), ALIGN);
12 assert_eq!(Some(DANGLING), NonNull::new(ALIGN as *mut u8));
16 fn layout_debug_shows_log2_of_alignment() {
17 // `Debug` is not stable, but here's what it does right now
18 let layout = Layout::from_size_align(24576, 8192).unwrap();
19 let s = format!("{:?}", layout);
20 assert_eq!(s, "Layout { size_: 24576, align_: 8192 (1 << 13) }");
23 // Running this normally doesn't do much, but it's also run in Miri, which
24 // will double-check that these are allowed by the validity invariants.
26 fn layout_accepts_all_valid_alignments() {
27 for align in 0..usize::BITS {
28 let layout = Layout::from_size_align(0, 1_usize << align).unwrap();
29 assert_eq!(layout.align(), 1_usize << align);