rust/tests/run-pass/heap.rs
2019-02-13 17:47:54 +01:00

61 lines
1.5 KiB
Rust

#![feature(box_syntax)]
#![feature(allocator_api)]
use std::alloc::{Global, Alloc, Layout, System};
fn make_box() -> Box<(i16, i16)> {
Box::new((1, 2))
}
fn make_box_syntax() -> Box<(i16, i16)> {
box (1, 2)
}
fn allocate_reallocate() {
let mut s = String::new();
// 6 byte heap alloc (__rust_allocate)
s.push_str("foobar");
assert_eq!(s.len(), 6);
assert_eq!(s.capacity(), 6);
// heap size doubled to 12 (__rust_reallocate)
s.push_str("baz");
assert_eq!(s.len(), 9);
assert_eq!(s.capacity(), 12);
// heap size reduced to 9 (__rust_reallocate)
s.shrink_to_fit();
assert_eq!(s.len(), 9);
assert_eq!(s.capacity(), 9);
}
fn check_overalign_requests<T: Alloc>(mut allocator: T) {
let size = 8;
let align = 16; // greater than size
let iterations = 1; // Miri is deterministic, no need to try many times
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 main() {
assert_eq!(*make_box(), (1, 2));
assert_eq!(*make_box_syntax(), (1, 2));
allocate_reallocate();
check_overalign_requests(System);
check_overalign_requests(Global);
}