97 lines
3.6 KiB
Rust
97 lines
3.6 KiB
Rust
#![feature(allocator_api, slice_ptr_get)]
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use std::ptr::NonNull;
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use std::alloc::{Global, Allocator, Layout, System};
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use std::slice;
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fn check_alloc<T: Allocator>(allocator: T) { unsafe {
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for &align in &[4, 8, 16, 32] {
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let layout_20 = Layout::from_size_align(20, align).unwrap();
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let layout_40 = Layout::from_size_align(40, 4*align).unwrap();
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let layout_10 = Layout::from_size_align(10, align/2).unwrap();
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for _ in 0..32 {
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let a = allocator.allocate(layout_20).unwrap().as_non_null_ptr();
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assert_eq!(a.as_ptr() as usize % layout_20.align(), 0, "pointer is incorrectly aligned");
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allocator.deallocate(a, layout_20);
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}
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let p1 = allocator.allocate_zeroed(layout_20).unwrap().as_non_null_ptr();
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assert_eq!(p1.as_ptr() as usize % layout_20.align(), 0, "pointer is incorrectly aligned");
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assert_eq!(*p1.as_ptr(), 0);
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// old size < new size
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let p2 = allocator.grow(p1, layout_20, layout_40).unwrap().as_non_null_ptr();
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assert_eq!(p2.as_ptr() as usize % layout_40.align(), 0, "pointer is incorrectly aligned");
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let slice = slice::from_raw_parts(p2.as_ptr(), 20);
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assert_eq!(&slice, &[0_u8; 20]);
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// old size == new size
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let p3 = allocator.grow(p2, layout_40, layout_40).unwrap().as_non_null_ptr();
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assert_eq!(p3.as_ptr() as usize % layout_40.align(), 0, "pointer is incorrectly aligned");
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let slice = slice::from_raw_parts(p3.as_ptr(), 20);
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assert_eq!(&slice, &[0_u8; 20]);
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// old size > new size
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let p4 = allocator.shrink(p3, layout_40, layout_10).unwrap().as_non_null_ptr();
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assert_eq!(p4.as_ptr() as usize % layout_10.align(), 0, "pointer is incorrectly aligned");
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let slice = slice::from_raw_parts(p4.as_ptr(), 10);
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assert_eq!(&slice, &[0_u8; 10]);
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allocator.deallocate(p4, layout_10);
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}
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} }
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fn check_align_requests<T: Allocator>(allocator: T) {
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for &size in &[2, 8, 64] { // size less than and bigger than alignment
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for &align in &[4, 8, 16, 32] { // Be sure to cover less than and bigger than `MIN_ALIGN` for all architectures
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let iterations = 32;
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unsafe {
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let pointers: Vec<_> = (0..iterations).map(|_| {
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allocator.allocate(Layout::from_size_align(size, align).unwrap()).unwrap().as_non_null_ptr()
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}).collect();
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for &ptr in &pointers {
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assert_eq!((ptr.as_ptr() as usize) % align, 0,
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"Got a pointer less aligned than requested")
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}
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// Clean up.
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for &ptr in &pointers {
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allocator.deallocate(ptr, Layout::from_size_align(size, align).unwrap())
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}
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}
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}
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}
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}
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fn global_to_box() {
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type T = [i32; 4];
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let l = Layout::new::<T>();
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// allocate manually with global allocator, then turn into Box and free there
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unsafe {
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let ptr = Global.allocate(l).unwrap().as_non_null_ptr().as_ptr() as *mut T;
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let b = Box::from_raw(ptr);
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drop(b);
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}
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}
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fn box_to_global() {
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type T = [i32; 4];
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let l = Layout::new::<T>();
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// allocate with the Box, then deallocate manually with global allocator
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unsafe {
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let b = Box::new(T::default());
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let ptr = Box::into_raw(b);
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Global.deallocate(NonNull::new(ptr as *mut u8).unwrap(), l);
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}
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}
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fn main() {
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check_alloc(System);
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check_alloc(Global);
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check_align_requests(System);
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check_align_requests(Global);
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global_to_box();
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box_to_global();
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}
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