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.
12 #![allow(unused_attributes)]
14 #![unstable(feature = "alloc_system",
15 reason = "this library is unlikely to be stabilized in its current \
18 #![feature(global_allocator)]
19 #![feature(allocator_api)]
21 #![feature(core_intrinsics)]
22 #![feature(staged_api)]
23 #![feature(rustc_attrs)]
24 #![cfg_attr(any(unix, target_os = "redox"), feature(libc))]
25 #![rustc_alloc_kind = "lib"]
27 // The minimum alignment guaranteed by the architecture. This value is used to
28 // add fast paths for low alignment values. In practice, the alignment is a
29 // constant at the call site and the branch will be optimized out.
30 #[cfg(all(any(target_arch = "x86",
33 target_arch = "powerpc",
34 target_arch = "powerpc64",
35 target_arch = "asmjs",
36 target_arch = "wasm32")))]
38 const MIN_ALIGN: usize = 8;
39 #[cfg(all(any(target_arch = "x86_64",
40 target_arch = "aarch64",
41 target_arch = "mips64",
42 target_arch = "s390x",
43 target_arch = "sparc64")))]
45 const MIN_ALIGN: usize = 16;
49 use self::alloc::heap::{Alloc, AllocErr, Layout, Excess, CannotReallocInPlace};
51 #[unstable(feature = "allocator_api", issue = "32838")]
54 #[unstable(feature = "allocator_api", issue = "32838")]
55 unsafe impl Alloc for System {
57 unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
58 (&*self).alloc(layout)
62 unsafe fn alloc_zeroed(&mut self, layout: Layout)
63 -> Result<*mut u8, AllocErr>
65 (&*self).alloc_zeroed(layout)
69 unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
70 (&*self).dealloc(ptr, layout)
74 unsafe fn realloc(&mut self,
77 new_layout: Layout) -> Result<*mut u8, AllocErr> {
78 (&*self).realloc(ptr, old_layout, new_layout)
81 fn oom(&mut self, err: AllocErr) -> ! {
86 fn usable_size(&self, layout: &Layout) -> (usize, usize) {
87 (&self).usable_size(layout)
91 unsafe fn alloc_excess(&mut self, layout: Layout) -> Result<Excess, AllocErr> {
92 (&*self).alloc_excess(layout)
96 unsafe fn realloc_excess(&mut self,
99 new_layout: Layout) -> Result<Excess, AllocErr> {
100 (&*self).realloc_excess(ptr, layout, new_layout)
104 unsafe fn grow_in_place(&mut self,
107 new_layout: Layout) -> Result<(), CannotReallocInPlace> {
108 (&*self).grow_in_place(ptr, layout, new_layout)
112 unsafe fn shrink_in_place(&mut self,
115 new_layout: Layout) -> Result<(), CannotReallocInPlace> {
116 (&*self).shrink_in_place(ptr, layout, new_layout)
120 #[cfg(any(unix, target_os = "redox"))]
129 use alloc::heap::{Alloc, AllocErr, Layout};
131 #[unstable(feature = "allocator_api", issue = "32838")]
132 unsafe impl<'a> Alloc for &'a System {
134 unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
135 let ptr = if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
136 libc::malloc(layout.size()) as *mut u8
138 aligned_malloc(&layout)
143 Err(AllocErr::Exhausted { request: layout })
148 unsafe fn alloc_zeroed(&mut self, layout: Layout)
149 -> Result<*mut u8, AllocErr>
151 if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
152 let ptr = libc::calloc(layout.size(), 1) as *mut u8;
156 Err(AllocErr::Exhausted { request: layout })
159 let ret = self.alloc(layout.clone());
160 if let Ok(ptr) = ret {
161 ptr::write_bytes(ptr, 0, layout.size());
168 unsafe fn dealloc(&mut self, ptr: *mut u8, _layout: Layout) {
169 libc::free(ptr as *mut libc::c_void)
173 unsafe fn realloc(&mut self,
176 new_layout: Layout) -> Result<*mut u8, AllocErr> {
177 if old_layout.align() != new_layout.align() {
178 return Err(AllocErr::Unsupported {
179 details: "cannot change alignment on `realloc`",
183 if new_layout.align() <= MIN_ALIGN && new_layout.align() <= new_layout.size(){
184 let ptr = libc::realloc(ptr as *mut libc::c_void, new_layout.size());
188 Err(AllocErr::Exhausted { request: new_layout })
191 let res = self.alloc(new_layout.clone());
192 if let Ok(new_ptr) = res {
193 let size = cmp::min(old_layout.size(), new_layout.size());
194 ptr::copy_nonoverlapping(ptr, new_ptr, size);
195 self.dealloc(ptr, old_layout);
201 fn oom(&mut self, err: AllocErr) -> ! {
202 use core::fmt::{self, Write};
204 // Print a message to stderr before aborting to assist with
205 // debugging. It is critical that this code does not allocate any
206 // memory since we are in an OOM situation. Any errors are ignored
207 // while printing since there's nothing we can do about them and we
208 // are about to exit anyways.
209 drop(writeln!(Stderr, "fatal runtime error: {}", err));
211 ::core::intrinsics::abort();
216 impl Write for Stderr {
217 fn write_str(&mut self, s: &str) -> fmt::Result {
219 libc::write(libc::STDERR_FILENO,
220 s.as_ptr() as *const libc::c_void,
229 #[cfg(any(target_os = "android", target_os = "redox", target_os = "solaris"))]
231 unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
232 // On android we currently target API level 9 which unfortunately
233 // doesn't have the `posix_memalign` API used below. Instead we use
234 // `memalign`, but this unfortunately has the property on some systems
235 // where the memory returned cannot be deallocated by `free`!
237 // Upon closer inspection, however, this appears to work just fine with
238 // Android, so for this platform we should be fine to call `memalign`
239 // (which is present in API level 9). Some helpful references could
240 // possibly be chromium using memalign [1], attempts at documenting that
241 // memalign + free is ok [2] [3], or the current source of chromium
242 // which still uses memalign on android [4].
244 // [1]: https://codereview.chromium.org/10796020/
245 // [2]: https://code.google.com/p/android/issues/detail?id=35391
246 // [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
247 // [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
248 // /memory/aligned_memory.cc
249 libc::memalign(layout.align(), layout.size()) as *mut u8
252 #[cfg(not(any(target_os = "android", target_os = "redox", target_os = "solaris")))]
254 unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
255 let mut out = ptr::null_mut();
256 let ret = libc::posix_memalign(&mut out, layout.align(), layout.size());
273 use alloc::heap::{Alloc, AllocErr, Layout, CannotReallocInPlace};
275 type LPVOID = *mut u8;
276 type HANDLE = LPVOID;
280 type LPDWORD = *mut DWORD;
281 type LPOVERLAPPED = *mut u8;
283 const STD_ERROR_HANDLE: DWORD = -12i32 as DWORD;
286 fn GetProcessHeap() -> HANDLE;
287 fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
288 fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
289 fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
290 fn GetLastError() -> DWORD;
291 fn WriteFile(hFile: HANDLE,
293 nNumberOfBytesToWrite: DWORD,
294 lpNumberOfBytesWritten: LPDWORD,
295 lpOverlapped: LPOVERLAPPED)
297 fn GetStdHandle(which: DWORD) -> HANDLE;
301 struct Header(*mut u8);
303 const HEAP_ZERO_MEMORY: DWORD = 0x00000008;
304 const HEAP_REALLOC_IN_PLACE_ONLY: DWORD = 0x00000010;
306 unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
307 &mut *(ptr as *mut Header).offset(-1)
310 unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
311 let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
312 *get_header(aligned) = Header(ptr);
317 unsafe fn allocate_with_flags(layout: Layout, flags: DWORD)
318 -> Result<*mut u8, AllocErr>
320 let ptr = if layout.align() <= MIN_ALIGN {
321 HeapAlloc(GetProcessHeap(), flags, layout.size())
323 let size = layout.size() + layout.align();
324 let ptr = HeapAlloc(GetProcessHeap(), flags, size);
328 align_ptr(ptr, layout.align())
332 Err(AllocErr::Exhausted { request: layout })
338 #[unstable(feature = "allocator_api", issue = "32838")]
339 unsafe impl<'a> Alloc for &'a System {
341 unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
342 allocate_with_flags(layout, 0)
346 unsafe fn alloc_zeroed(&mut self, layout: Layout)
347 -> Result<*mut u8, AllocErr>
349 allocate_with_flags(layout, HEAP_ZERO_MEMORY)
353 unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
354 if layout.align() <= MIN_ALIGN {
355 let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID);
356 debug_assert!(err != 0, "Failed to free heap memory: {}",
359 let header = get_header(ptr);
360 let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
361 debug_assert!(err != 0, "Failed to free heap memory: {}",
367 unsafe fn realloc(&mut self,
370 new_layout: Layout) -> Result<*mut u8, AllocErr> {
371 if old_layout.align() != new_layout.align() {
372 return Err(AllocErr::Unsupported {
373 details: "cannot change alignment on `realloc`",
377 if new_layout.align() <= MIN_ALIGN {
378 let ptr = HeapReAlloc(GetProcessHeap(),
385 Err(AllocErr::Exhausted { request: new_layout })
388 let res = self.alloc(new_layout.clone());
389 if let Ok(new_ptr) = res {
390 let size = cmp::min(old_layout.size(), new_layout.size());
391 ptr::copy_nonoverlapping(ptr, new_ptr, size);
392 self.dealloc(ptr, old_layout);
399 unsafe fn grow_in_place(&mut self,
402 new_layout: Layout) -> Result<(), CannotReallocInPlace> {
403 self.shrink_in_place(ptr, layout, new_layout)
407 unsafe fn shrink_in_place(&mut self,
410 new_layout: Layout) -> Result<(), CannotReallocInPlace> {
411 if old_layout.align() != new_layout.align() {
412 return Err(CannotReallocInPlace)
415 let new = if new_layout.align() <= MIN_ALIGN {
416 HeapReAlloc(GetProcessHeap(),
417 HEAP_REALLOC_IN_PLACE_ONLY,
421 let header = get_header(ptr);
422 HeapReAlloc(GetProcessHeap(),
423 HEAP_REALLOC_IN_PLACE_ONLY,
425 new_layout.size() + new_layout.align())
428 Err(CannotReallocInPlace)
434 fn oom(&mut self, err: AllocErr) -> ! {
435 use core::fmt::{self, Write};
437 // Same as with unix we ignore all errors here
438 drop(writeln!(Stderr, "fatal runtime error: {}", err));
440 ::core::intrinsics::abort();
445 impl Write for Stderr {
446 fn write_str(&mut self, s: &str) -> fmt::Result {
448 // WriteFile silently fails if it is passed an invalid
449 // handle, so there is no need to check the result of
451 WriteFile(GetStdHandle(STD_ERROR_HANDLE),
452 s.as_ptr() as LPVOID,
464 // This is an implementation of a global allocator on the wasm32 platform when
465 // emscripten is not in use. In that situation there's no actual runtime for us
466 // to lean on for allocation, so instead we provide our own!
468 // The wasm32 instruction set has two instructions for getting the current
469 // amount of memory and growing the amount of memory. These instructions are the
470 // foundation on which we're able to build an allocator, so we do so! Note that
471 // the instructions are also pretty "global" and this is the "global" allocator
474 // The current allocator here is the `dlmalloc` crate which we've got included
475 // in the rust-lang/rust repository as a submodule. The crate is a port of
476 // dlmalloc.c from C to Rust and is basically just so we can have "pure Rust"
477 // for now which is currently technically required (can't link with C yet).
479 // The crate itself provides a global allocator which on wasm has no
480 // synchronization as there are no threads!
481 #[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
483 extern crate dlmalloc;
485 use alloc::heap::{Alloc, AllocErr, Layout, Excess, CannotReallocInPlace};
487 use self::dlmalloc::GlobalDlmalloc;
489 #[unstable(feature = "allocator_api", issue = "32838")]
490 unsafe impl<'a> Alloc for &'a System {
492 unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
493 GlobalDlmalloc.alloc(layout)
497 unsafe fn alloc_zeroed(&mut self, layout: Layout)
498 -> Result<*mut u8, AllocErr>
500 GlobalDlmalloc.alloc_zeroed(layout)
504 unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
505 GlobalDlmalloc.dealloc(ptr, layout)
509 unsafe fn realloc(&mut self,
512 new_layout: Layout) -> Result<*mut u8, AllocErr> {
513 GlobalDlmalloc.realloc(ptr, old_layout, new_layout)
517 fn usable_size(&self, layout: &Layout) -> (usize, usize) {
518 GlobalDlmalloc.usable_size(layout)
522 unsafe fn alloc_excess(&mut self, layout: Layout) -> Result<Excess, AllocErr> {
523 GlobalDlmalloc.alloc_excess(layout)
527 unsafe fn realloc_excess(&mut self,
530 new_layout: Layout) -> Result<Excess, AllocErr> {
531 GlobalDlmalloc.realloc_excess(ptr, layout, new_layout)
535 unsafe fn grow_in_place(&mut self,
538 new_layout: Layout) -> Result<(), CannotReallocInPlace> {
539 GlobalDlmalloc.grow_in_place(ptr, layout, new_layout)
543 unsafe fn shrink_in_place(&mut self,
546 new_layout: Layout) -> Result<(), CannotReallocInPlace> {
547 GlobalDlmalloc.shrink_in_place(ptr, layout, new_layout)