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"]
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(any(unix, target_os = "redox"), 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 target_arch = "wasm32")))]
34 const MIN_ALIGN: usize = 8;
35 #[cfg(all(any(target_arch = "x86_64",
36 target_arch = "aarch64",
37 target_arch = "mips64",
38 target_arch = "s390x",
39 target_arch = "sparc64")))]
40 const MIN_ALIGN: usize = 16;
43 pub extern "C" fn __rust_allocate(size: usize, align: usize) -> *mut u8 {
44 unsafe { imp::allocate(size, align) }
48 pub extern "C" fn __rust_deallocate(ptr: *mut u8, old_size: usize, align: usize) {
49 unsafe { imp::deallocate(ptr, old_size, align) }
53 pub extern "C" fn __rust_reallocate(ptr: *mut u8,
58 unsafe { imp::reallocate(ptr, old_size, size, align) }
62 pub extern "C" fn __rust_reallocate_inplace(ptr: *mut u8,
67 unsafe { imp::reallocate_inplace(ptr, old_size, size, align) }
71 pub extern "C" fn __rust_usable_size(size: usize, align: usize) -> usize {
72 imp::usable_size(size, align)
75 #[cfg(any(unix, target_os = "redox"))]
83 pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
84 if align <= MIN_ALIGN {
85 libc::malloc(size as libc::size_t) as *mut u8
87 aligned_malloc(size, align)
91 #[cfg(any(target_os = "android", target_os = "redox"))]
92 unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
93 // On android we currently target API level 9 which unfortunately
94 // doesn't have the `posix_memalign` API used below. Instead we use
95 // `memalign`, but this unfortunately has the property on some systems
96 // where the memory returned cannot be deallocated by `free`!
98 // Upon closer inspection, however, this appears to work just fine with
99 // Android, so for this platform we should be fine to call `memalign`
100 // (which is present in API level 9). Some helpful references could
101 // possibly be chromium using memalign [1], attempts at documenting that
102 // memalign + free is ok [2] [3], or the current source of chromium
103 // which still uses memalign on android [4].
105 // [1]: https://codereview.chromium.org/10796020/
106 // [2]: https://code.google.com/p/android/issues/detail?id=35391
107 // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
108 // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
109 // /memory/aligned_memory.cc
110 libc::memalign(align as libc::size_t, size as libc::size_t) as *mut u8
113 #[cfg(not(any(target_os = "android", target_os = "redox")))]
114 unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
115 let mut out = ptr::null_mut();
116 let ret = libc::posix_memalign(&mut out, align as libc::size_t, size as libc::size_t);
124 pub unsafe fn reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8 {
125 if align <= MIN_ALIGN {
126 libc::realloc(ptr as *mut libc::c_void, size as libc::size_t) as *mut u8
128 let new_ptr = allocate(size, align);
129 if !new_ptr.is_null() {
130 ptr::copy(ptr, new_ptr, cmp::min(size, old_size));
131 deallocate(ptr, old_size, align);
137 pub unsafe fn reallocate_inplace(_ptr: *mut u8,
145 pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, _align: usize) {
146 libc::free(ptr as *mut libc::c_void)
149 pub fn usable_size(size: usize, _align: usize) -> usize {
159 type LPVOID = *mut u8;
160 type HANDLE = LPVOID;
166 fn GetProcessHeap() -> HANDLE;
167 fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
168 fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
169 fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
170 fn GetLastError() -> DWORD;
174 struct Header(*mut u8);
176 const HEAP_REALLOC_IN_PLACE_ONLY: DWORD = 0x00000010;
178 unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
179 &mut *(ptr as *mut Header).offset(-1)
182 unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
183 let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
184 *get_header(aligned) = Header(ptr);
188 pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
189 if align <= MIN_ALIGN {
190 HeapAlloc(GetProcessHeap(), 0, size as SIZE_T) as *mut u8
192 let ptr = HeapAlloc(GetProcessHeap(), 0, (size + align) as SIZE_T) as *mut u8;
196 align_ptr(ptr, align)
200 pub unsafe fn reallocate(ptr: *mut u8, _old_size: usize, size: usize, align: usize) -> *mut u8 {
201 if align <= MIN_ALIGN {
202 HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, size as SIZE_T) as *mut u8
204 let header = get_header(ptr);
205 let new = HeapReAlloc(GetProcessHeap(),
208 (size + align) as SIZE_T) as *mut u8;
212 align_ptr(new, align)
216 pub unsafe fn reallocate_inplace(ptr: *mut u8,
221 if align <= MIN_ALIGN {
222 let new = HeapReAlloc(GetProcessHeap(),
223 HEAP_REALLOC_IN_PLACE_ONLY,
225 size as SIZE_T) as *mut u8;
226 if new.is_null() { old_size } else { size }
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, "Failed to free heap memory: {}", GetLastError());
237 let header = get_header(ptr);
238 let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
239 debug_assert!(err != 0, "Failed to free heap memory: {}", GetLastError());
243 pub fn usable_size(size: usize, _align: usize) -> usize {