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 const MIN_ALIGN: usize = 16;
39 pub extern "C" fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
40 unsafe { imp::allocate(size, align) }
44 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
45 unsafe { imp::deallocate(ptr, old_size, align) }
49 pub extern "C" fn __rust_reallocate(ptr: *mut u8,
54 unsafe { imp::reallocate(ptr, old_size, size, align) }
58 pub extern "C" fn __rust_reallocate_inplace(ptr: *mut u8,
63 unsafe { imp::reallocate_inplace(ptr, old_size, size, align) }
67 pub extern "C" fn __rust_usable_size(size: usize, align: usize) -> usize {
68 imp::usable_size(size, align)
79 pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
80 if align <= MIN_ALIGN {
81 libc::malloc(size as libc::size_t) as *mut u8
83 aligned_malloc(size, align)
87 #[cfg(target_os = "android")]
88 unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
89 // On android we currently target API level 9 which unfortunately
90 // doesn't have the `posix_memalign` API used below. Instead we use
91 // `memalign`, but this unfortunately has the property on some systems
92 // where the memory returned cannot be deallocated by `free`!
94 // Upon closer inspection, however, this appears to work just fine with
95 // Android, so for this platform we should be fine to call `memalign`
96 // (which is present in API level 9). Some helpful references could
97 // possibly be chromium using memalign [1], attempts at documenting that
98 // memalign + free is ok [2] [3], or the current source of chromium
99 // which still uses memalign on android [4].
101 // [1]: https://codereview.chromium.org/10796020/
102 // [2]: https://code.google.com/p/android/issues/detail?id=35391
103 // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
104 // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
105 // /memory/aligned_memory.cc
106 libc::memalign(align as libc::size_t, size as libc::size_t) as *mut u8
109 #[cfg(not(target_os = "android"))]
110 unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
111 let mut out = ptr::null_mut();
112 let ret = libc::posix_memalign(&mut out, align as libc::size_t, size as libc::size_t);
120 pub unsafe fn reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8 {
121 if align <= MIN_ALIGN {
122 libc::realloc(ptr as *mut libc::c_void, size as libc::size_t) as *mut u8
124 let new_ptr = allocate(size, align);
125 if !new_ptr.is_null() {
126 ptr::copy(ptr, new_ptr, cmp::min(size, old_size));
127 deallocate(ptr, old_size, align);
133 pub unsafe fn reallocate_inplace(_ptr: *mut u8,
141 pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, _align: usize) {
142 libc::free(ptr as *mut libc::c_void)
145 pub fn usable_size(size: usize, _align: usize) -> usize {
155 type LPVOID = *mut u8;
156 type HANDLE = LPVOID;
162 fn GetProcessHeap() -> HANDLE;
163 fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
164 fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
165 fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
169 struct Header(*mut u8);
171 const HEAP_REALLOC_IN_PLACE_ONLY: DWORD = 0x00000010;
173 unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
174 &mut *(ptr as *mut Header).offset(-1)
177 unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
178 let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
179 *get_header(aligned) = Header(ptr);
183 pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
184 if align <= MIN_ALIGN {
185 HeapAlloc(GetProcessHeap(), 0, size as SIZE_T) as *mut u8
187 let ptr = HeapAlloc(GetProcessHeap(), 0, (size + align) as SIZE_T) as *mut u8;
191 align_ptr(ptr, align)
195 pub unsafe fn reallocate(ptr: *mut u8, _old_size: usize, size: usize, align: usize) -> *mut u8 {
196 if align <= MIN_ALIGN {
197 HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, size as SIZE_T) as *mut u8
199 let header = get_header(ptr);
200 let new = HeapReAlloc(GetProcessHeap(),
203 (size + align) as SIZE_T) as *mut u8;
207 align_ptr(new, align)
211 pub unsafe fn reallocate_inplace(ptr: *mut u8,
216 if align <= MIN_ALIGN {
217 let new = HeapReAlloc(GetProcessHeap(),
218 HEAP_REALLOC_IN_PLACE_ONLY,
220 size as SIZE_T) as *mut u8;
231 pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, align: usize) {
232 if align <= MIN_ALIGN {
233 let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID);
234 debug_assert!(err != 0);
236 let header = get_header(ptr);
237 let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
238 debug_assert!(err != 0);
242 pub fn usable_size(size: usize, _align: usize) -> usize {