// compile-flag: -Zmiri-seed= #![feature(allocator_api)] use std::ptr::NonNull; use std::alloc::{Global, Alloc, Layout, System}; use std::slice; fn check_alloc(mut allocator: T) { unsafe { let layout = Layout::from_size_align(20, 4).unwrap(); let a = allocator.alloc(layout).unwrap(); allocator.dealloc(a, layout); let p1 = allocator.alloc_zeroed(layout).unwrap(); let p2 = allocator.realloc(p1, Layout::from_size_align(20, 4).unwrap(), 40).unwrap(); let slice = slice::from_raw_parts(p2.as_ptr(), 20); assert_eq!(&slice, &[0_u8; 20]); // old size == new size let p3 = allocator.realloc(p2, Layout::from_size_align(40, 4).unwrap(), 40).unwrap(); let slice = slice::from_raw_parts(p3.as_ptr(), 20); assert_eq!(&slice, &[0_u8; 20]); // old size > new size let p4 = allocator.realloc(p3, Layout::from_size_align(40, 4).unwrap(), 10).unwrap(); let slice = slice::from_raw_parts(p4.as_ptr(), 10); assert_eq!(&slice, &[0_u8; 10]); allocator.dealloc(p4, Layout::from_size_align(10, 4).unwrap()); } } fn check_overalign_requests(mut allocator: T) { let size = 8; // Greater than `size`. let align = 16; // Miri is deterministic; no need to try many times. let iterations = 1; unsafe { let pointers: Vec<_> = (0..iterations).map(|_| { allocator.alloc(Layout::from_size_align(size, align).unwrap()).unwrap() }).collect(); for &ptr in &pointers { assert_eq!((ptr.as_ptr() as usize) % align, 0, "Got a pointer less aligned than requested") } // Clean up. for &ptr in &pointers { allocator.dealloc(ptr, Layout::from_size_align(size, align).unwrap()) } } } fn global_to_box() { type T = [i32; 4]; let l = Layout::new::(); // allocate manually with global allocator, then turn into Box and free there unsafe { let ptr = Global.alloc(l).unwrap().as_ptr() as *mut T; let b = Box::from_raw(ptr); drop(b); } } fn box_to_global() { type T = [i32; 4]; let l = Layout::new::(); // allocate with the Box, then deallocate manually with global allocator unsafe { let b = Box::new(T::default()); let ptr = Box::into_raw(b); Global.dealloc(NonNull::new(ptr as *mut u8).unwrap(), l); } } fn main() { check_alloc(System); check_alloc(Global); check_overalign_requests(System); check_overalign_requests(Global); global_to_box(); box_to_global(); }