2 // alloc::heap::reallocate test.
4 // Ideally this would be revised to use no_std, but for now it serves
5 // well enough to reproduce (and illustrate) the bug from #16687.
7 #![feature(allocator_api)]
8 #![feature(slice_ptr_get)]
10 use std::alloc::{handle_alloc_error, Allocator, Global, Layout};
11 use std::ptr::{self, NonNull};
15 assert!(test_triangle());
19 unsafe fn test_triangle() -> bool {
20 static COUNT: usize = 16;
21 let mut ascend = vec![ptr::null_mut(); COUNT];
22 let ascend = &mut *ascend;
23 static ALIGN: usize = 1;
25 // Checks that `ascend` forms triangle of ascending size formed
26 // from pairs of rows (where each pair of rows is equally sized),
27 // and the elements of the triangle match their row-pair index.
28 unsafe fn sanity_check(ascend: &[*mut u8]) {
29 for i in 0..COUNT / 2 {
30 let (p0, p1, size) = (ascend[2 * i], ascend[2 * i + 1], idx_to_size(i));
32 assert_eq!(*p0.add(j), i as u8);
33 assert_eq!(*p1.add(j), i as u8);
38 static PRINT: bool = false;
40 unsafe fn allocate(layout: Layout) -> *mut u8 {
42 println!("allocate({:?})", layout);
45 let ptr = Global.allocate(layout).unwrap_or_else(|_| handle_alloc_error(layout));
48 println!("allocate({:?}) = {:?}", layout, ptr);
54 unsafe fn deallocate(ptr: *mut u8, layout: Layout) {
56 println!("deallocate({:?}, {:?}", ptr, layout);
59 Global.deallocate(NonNull::new_unchecked(ptr), layout);
62 unsafe fn reallocate(ptr: *mut u8, old: Layout, new: Layout) -> *mut u8 {
64 println!("reallocate({:?}, old={:?}, new={:?})", ptr, old, new);
67 let memory = if new.size() > old.size() {
68 Global.grow(NonNull::new_unchecked(ptr), old, new)
70 Global.shrink(NonNull::new_unchecked(ptr), old, new)
73 let ptr = memory.unwrap_or_else(|_| handle_alloc_error(new));
76 println!("reallocate({:?}, old={:?}, new={:?}) = {:?}", ptr, old, new, ptr);
81 fn idx_to_size(i: usize) -> usize {
85 // Allocate pairs of rows that form a triangle shape. (Hope is
86 // that at least two rows will be allocated near each other, so
87 // that we trigger the bug (a buffer overrun) in an observable
89 for i in 0..COUNT / 2 {
90 let size = idx_to_size(i);
91 ascend[2 * i] = allocate(Layout::from_size_align(size, ALIGN).unwrap());
92 ascend[2 * i + 1] = allocate(Layout::from_size_align(size, ALIGN).unwrap());
95 // Initialize each pair of rows to distinct value.
96 for i in 0..COUNT / 2 {
97 let (p0, p1, size) = (ascend[2 * i], ascend[2 * i + 1], idx_to_size(i));
100 *p1.add(j) = i as u8;
104 sanity_check(&*ascend);
105 test_1(ascend); // triangle -> square
106 test_2(ascend); // square -> triangle
107 test_3(ascend); // triangle -> square
108 test_4(ascend); // square -> triangle
110 for i in 0..COUNT / 2 {
111 let size = idx_to_size(i);
112 deallocate(ascend[2 * i], Layout::from_size_align(size, ALIGN).unwrap());
113 deallocate(ascend[2 * i + 1], Layout::from_size_align(size, ALIGN).unwrap());
118 // Test 1: turn the triangle into a square (in terms of
119 // allocation; initialized portion remains a triangle) by
120 // realloc'ing each row from top to bottom, and checking all the
122 unsafe fn test_1(ascend: &mut [*mut u8]) {
123 let new_size = idx_to_size(COUNT - 1);
124 let new = Layout::from_size_align(new_size, ALIGN).unwrap();
125 for i in 0..COUNT / 2 {
126 let (p0, p1, old_size) = (ascend[2 * i], ascend[2 * i + 1], idx_to_size(i));
127 assert!(old_size < new_size);
128 let old = Layout::from_size_align(old_size, ALIGN).unwrap();
130 ascend[2 * i] = reallocate(p0, old.clone(), new.clone());
131 sanity_check(&*ascend);
133 ascend[2 * i + 1] = reallocate(p1, old.clone(), new.clone());
134 sanity_check(&*ascend);
138 // Test 2: turn the square back into a triangle, top to bottom.
139 unsafe fn test_2(ascend: &mut [*mut u8]) {
140 let old_size = idx_to_size(COUNT - 1);
141 let old = Layout::from_size_align(old_size, ALIGN).unwrap();
142 for i in 0..COUNT / 2 {
143 let (p0, p1, new_size) = (ascend[2 * i], ascend[2 * i + 1], idx_to_size(i));
144 assert!(new_size < old_size);
145 let new = Layout::from_size_align(new_size, ALIGN).unwrap();
147 ascend[2 * i] = reallocate(p0, old.clone(), new.clone());
148 sanity_check(&*ascend);
150 ascend[2 * i + 1] = reallocate(p1, old.clone(), new.clone());
151 sanity_check(&*ascend);
155 // Test 3: turn triangle into a square, bottom to top.
156 unsafe fn test_3(ascend: &mut [*mut u8]) {
157 let new_size = idx_to_size(COUNT - 1);
158 let new = Layout::from_size_align(new_size, ALIGN).unwrap();
159 for i in (0..COUNT / 2).rev() {
160 let (p0, p1, old_size) = (ascend[2 * i], ascend[2 * i + 1], idx_to_size(i));
161 assert!(old_size < new_size);
162 let old = Layout::from_size_align(old_size, ALIGN).unwrap();
164 ascend[2 * i + 1] = reallocate(p1, old.clone(), new.clone());
165 sanity_check(&*ascend);
167 ascend[2 * i] = reallocate(p0, old.clone(), new.clone());
168 sanity_check(&*ascend);
172 // Test 4: turn the square back into a triangle, bottom to top.
173 unsafe fn test_4(ascend: &mut [*mut u8]) {
174 let old_size = idx_to_size(COUNT - 1);
175 let old = Layout::from_size_align(old_size, ALIGN).unwrap();
176 for i in (0..COUNT / 2).rev() {
177 let (p0, p1, new_size) = (ascend[2 * i], ascend[2 * i + 1], idx_to_size(i));
178 assert!(new_size < old_size);
179 let new = Layout::from_size_align(new_size, ALIGN).unwrap();
181 ascend[2 * i + 1] = reallocate(p1, old.clone(), new.clone());
182 sanity_check(&*ascend);
184 ascend[2 * i] = reallocate(p0, old.clone(), new.clone());
185 sanity_check(&*ascend);