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Commit | Line | Data |
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532ac7d7 | 1 | use crate::alloc::{GlobalAlloc, Layout, System}; |
60c5eb7d XL |
2 | use crate::ptr; |
3 | use crate::sys_common::alloc::{realloc_fallback, MIN_ALIGN}; | |
a1dfa0c6 XL |
4 | |
5 | #[stable(feature = "alloc_system_type", since = "1.28.0")] | |
6 | unsafe impl GlobalAlloc for System { | |
7 | #[inline] | |
8 | unsafe fn alloc(&self, layout: Layout) -> *mut u8 { | |
416331ca XL |
9 | // jemalloc provides alignment less than MIN_ALIGN for small allocations. |
10 | // So only rely on MIN_ALIGN if size >= align. | |
11 | // Also see <https://github.com/rust-lang/rust/issues/45955> and | |
12 | // <https://github.com/rust-lang/rust/issues/62251#issuecomment-507580914>. | |
a1dfa0c6 XL |
13 | if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() { |
14 | libc::malloc(layout.size()) as *mut u8 | |
15 | } else { | |
16 | #[cfg(target_os = "macos")] | |
17 | { | |
18 | if layout.align() > (1 << 31) { | |
60c5eb7d | 19 | return ptr::null_mut(); |
a1dfa0c6 XL |
20 | } |
21 | } | |
22 | aligned_malloc(&layout) | |
23 | } | |
24 | } | |
25 | ||
26 | #[inline] | |
27 | unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { | |
416331ca | 28 | // See the comment above in `alloc` for why this check looks the way it does. |
a1dfa0c6 XL |
29 | if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() { |
30 | libc::calloc(layout.size(), 1) as *mut u8 | |
31 | } else { | |
416331ca | 32 | let ptr = self.alloc(layout); |
a1dfa0c6 XL |
33 | if !ptr.is_null() { |
34 | ptr::write_bytes(ptr, 0, layout.size()); | |
35 | } | |
36 | ptr | |
37 | } | |
38 | } | |
39 | ||
40 | #[inline] | |
41 | unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) { | |
42 | libc::free(ptr as *mut libc::c_void) | |
43 | } | |
44 | ||
45 | #[inline] | |
46 | unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 { | |
47 | if layout.align() <= MIN_ALIGN && layout.align() <= new_size { | |
48 | libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8 | |
49 | } else { | |
50 | realloc_fallback(self, ptr, layout, new_size) | |
51 | } | |
52 | } | |
53 | } | |
54 | ||
ba9703b0 XL |
55 | #[cfg(any( |
56 | target_os = "android", | |
57 | target_os = "illumos", | |
58 | target_os = "redox", | |
59 | target_os = "solaris" | |
60 | ))] | |
a1dfa0c6 XL |
61 | #[inline] |
62 | unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { | |
63 | // On android we currently target API level 9 which unfortunately | |
64 | // doesn't have the `posix_memalign` API used below. Instead we use | |
65 | // `memalign`, but this unfortunately has the property on some systems | |
66 | // where the memory returned cannot be deallocated by `free`! | |
67 | // | |
68 | // Upon closer inspection, however, this appears to work just fine with | |
69 | // Android, so for this platform we should be fine to call `memalign` | |
70 | // (which is present in API level 9). Some helpful references could | |
71 | // possibly be chromium using memalign [1], attempts at documenting that | |
72 | // memalign + free is ok [2] [3], or the current source of chromium | |
73 | // which still uses memalign on android [4]. | |
74 | // | |
75 | // [1]: https://codereview.chromium.org/10796020/ | |
76 | // [2]: https://code.google.com/p/android/issues/detail?id=35391 | |
77 | // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579 | |
78 | // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/ | |
79 | // /memory/aligned_memory.cc | |
80 | libc::memalign(layout.align(), layout.size()) as *mut u8 | |
81 | } | |
82 | ||
ba9703b0 XL |
83 | #[cfg(not(any( |
84 | target_os = "android", | |
85 | target_os = "illumos", | |
86 | target_os = "redox", | |
87 | target_os = "solaris" | |
88 | )))] | |
a1dfa0c6 XL |
89 | #[inline] |
90 | unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 { | |
91 | let mut out = ptr::null_mut(); | |
416331ca XL |
92 | // posix_memalign requires that the alignment be a multiple of `sizeof(void*)`. |
93 | // Since these are all powers of 2, we can just use max. | |
94 | let align = layout.align().max(crate::mem::size_of::<usize>()); | |
95 | let ret = libc::posix_memalign(&mut out, align, layout.size()); | |
60c5eb7d | 96 | if ret != 0 { ptr::null_mut() } else { out as *mut u8 } |
a1dfa0c6 | 97 | } |