src/liballoc/tests/heap.rs

// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use alloc_system::System;
use std::heap::{Heap, Alloc, Layout};

/// https://github.com/rust-lang/rust/issues/45955
///
/// Note that `#[global_allocator]` is not used,
/// so `liballoc_jemalloc` is linked (on some platforms).
#[test]
fn alloc_system_overaligned_request() {
    check_overalign_requests(System)
}

#[test]
fn std_heap_overaligned_request() {
    check_overalign_requests(Heap)
}

fn check_overalign_requests<T: Alloc>(mut allocator: T) {
    let size = 8;
    let align = 16; // greater than size
    let iterations = 100;
    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 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())
        }
    }
}