1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![crate_name = "alloc_system"]
12 #![crate_type = "rlib"]
15 #![cfg_attr(not(stage0), deny(warnings))]
16 #![unstable(feature = "alloc_system",
17 reason = "this library is unlikely to be stabilized in its current \
20 #![feature(allocator)]
21 #![feature(staged_api)]
22 #![cfg_attr(unix, feature(libc))]
24 // The minimum alignment guaranteed by the architecture. This value is used to
25 // add fast paths for low alignment values. In practice, the alignment is a
26 // constant at the call site and the branch will be optimized out.
27 #[cfg(all(any(target_arch = "x86",
30 target_arch = "powerpc",
31 target_arch = "powerpc64",
32 target_arch = "asmjs")))]
33 const MIN_ALIGN: usize = 8;
34 #[cfg(all(any(target_arch = "x86_64",
35 target_arch = "aarch64",
36 target_arch = "mips64")))]
37 const MIN_ALIGN: usize = 16;
40 pub extern "C" fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
41 unsafe { imp::allocate(size, align) }
45 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
46 unsafe { imp::deallocate(ptr, old_size, align) }
50 pub extern "C" fn __rust_reallocate(ptr: *mut u8,
55 unsafe { imp::reallocate(ptr, old_size, size, align) }
59 pub extern "C" fn __rust_reallocate_inplace(ptr: *mut u8,
64 unsafe { imp::reallocate_inplace(ptr, old_size, size, align) }
68 pub extern "C" fn __rust_usable_size(size: usize, align: usize) -> usize {
69 imp::usable_size(size, align)
80 pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
81 if align <= MIN_ALIGN {
82 libc::malloc(size as libc::size_t) as *mut u8
84 aligned_malloc(size, align)
88 #[cfg(target_os = "android")]
89 unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
90 // On android we currently target API level 9 which unfortunately
91 // doesn't have the `posix_memalign` API used below. Instead we use
92 // `memalign`, but this unfortunately has the property on some systems
93 // where the memory returned cannot be deallocated by `free`!
95 // Upon closer inspection, however, this appears to work just fine with
96 // Android, so for this platform we should be fine to call `memalign`
97 // (which is present in API level 9). Some helpful references could
98 // possibly be chromium using memalign [1], attempts at documenting that
99 // memalign + free is ok [2] [3], or the current source of chromium
100 // which still uses memalign on android [4].
102 // [1]: https://codereview.chromium.org/10796020/
103 // [2]: https://code.google.com/p/android/issues/detail?id=35391
104 // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
105 // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
106 // /memory/aligned_memory.cc
107 libc::memalign(align as libc::size_t, size as libc::size_t) as *mut u8
110 #[cfg(not(target_os = "android"))]
111 unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
112 let mut out = ptr::null_mut();
113 let ret = libc::posix_memalign(&mut out, align as libc::size_t, size as libc::size_t);
121 pub unsafe fn reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8 {
122 if align <= MIN_ALIGN {
123 libc::realloc(ptr as *mut libc::c_void, size as libc::size_t) as *mut u8
125 let new_ptr = allocate(size, align);
126 if !new_ptr.is_null() {
127 ptr::copy(ptr, new_ptr, cmp::min(size, old_size));
128 deallocate(ptr, old_size, align);
134 pub unsafe fn reallocate_inplace(_ptr: *mut u8,
142 pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, _align: usize) {
143 libc::free(ptr as *mut libc::c_void)
146 pub fn usable_size(size: usize, _align: usize) -> usize {
156 type LPVOID = *mut u8;
157 type HANDLE = LPVOID;
163 fn GetProcessHeap() -> HANDLE;
164 fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
165 fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
166 fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
170 struct Header(*mut u8);
172 const HEAP_REALLOC_IN_PLACE_ONLY: DWORD = 0x00000010;
174 unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
175 &mut *(ptr as *mut Header).offset(-1)
178 unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
179 let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
180 *get_header(aligned) = Header(ptr);
184 pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
185 if align <= MIN_ALIGN {
186 HeapAlloc(GetProcessHeap(), 0, size as SIZE_T) as *mut u8
188 let ptr = HeapAlloc(GetProcessHeap(), 0, (size + align) as SIZE_T) as *mut u8;
192 align_ptr(ptr, align)
196 pub unsafe fn reallocate(ptr: *mut u8, _old_size: usize, size: usize, align: usize) -> *mut u8 {
197 if align <= MIN_ALIGN {
198 HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, size as SIZE_T) as *mut u8
200 let header = get_header(ptr);
201 let new = HeapReAlloc(GetProcessHeap(),
204 (size + align) as SIZE_T) as *mut u8;
208 align_ptr(new, align)
212 pub unsafe fn reallocate_inplace(ptr: *mut u8,
217 if align <= MIN_ALIGN {
218 let new = HeapReAlloc(GetProcessHeap(),
219 HEAP_REALLOC_IN_PLACE_ONLY,
221 size as SIZE_T) as *mut u8;
232 pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, align: usize) {
233 if align <= MIN_ALIGN {
234 let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID);
235 debug_assert!(err != 0);
237 let header = get_header(ptr);
238 let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
239 debug_assert!(err != 0);
243 pub fn usable_size(size: usize, _align: usize) -> usize {