524 lines
19 KiB
Rust
524 lines
19 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![no_std]
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#![allow(unused_attributes)]
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#![unstable(feature = "alloc_system",
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reason = "this library is unlikely to be stabilized in its current \
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form or name",
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issue = "32838")]
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#![feature(global_allocator)]
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#![feature(allocator_api)]
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#![feature(core_intrinsics)]
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#![feature(staged_api)]
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#![feature(rustc_attrs)]
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#![cfg_attr(any(unix, target_os = "cloudabi", target_os = "redox"), feature(libc))]
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#![rustc_alloc_kind = "lib"]
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// The minimum alignment guaranteed by the architecture. This value is used to
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// add fast paths for low alignment values.
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#[cfg(all(any(target_arch = "x86",
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target_arch = "arm",
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target_arch = "mips",
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target_arch = "powerpc",
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target_arch = "powerpc64",
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target_arch = "asmjs",
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target_arch = "wasm32")))]
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#[allow(dead_code)]
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const MIN_ALIGN: usize = 8;
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#[cfg(all(any(target_arch = "x86_64",
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target_arch = "aarch64",
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target_arch = "mips64",
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target_arch = "s390x",
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target_arch = "sparc64")))]
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#[allow(dead_code)]
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const MIN_ALIGN: usize = 16;
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use core::alloc::{Alloc, AllocErr, Layout, Excess, CannotReallocInPlace};
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#[unstable(feature = "allocator_api", issue = "32838")]
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pub struct System;
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#[unstable(feature = "allocator_api", issue = "32838")]
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unsafe impl Alloc for System {
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#[inline]
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unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
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Alloc::alloc(&mut &*self, layout)
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}
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#[inline]
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unsafe fn alloc_zeroed(&mut self, layout: Layout)
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-> Result<*mut u8, AllocErr>
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{
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Alloc::alloc_zeroed(&mut &*self, layout)
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}
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#[inline]
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unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
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Alloc::dealloc(&mut &*self, ptr, layout)
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}
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#[inline]
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unsafe fn realloc(&mut self,
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ptr: *mut u8,
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old_layout: Layout,
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new_size: usize) -> Result<*mut u8, AllocErr> {
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Alloc::realloc(&mut &*self, ptr, old_layout, new_size)
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}
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fn oom(&mut self) -> ! {
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Alloc::oom(&mut &*self)
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}
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#[inline]
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fn usable_size(&self, layout: &Layout) -> (usize, usize) {
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Alloc::usable_size(&mut &*self, layout)
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}
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#[inline]
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unsafe fn alloc_excess(&mut self, layout: Layout) -> Result<Excess, AllocErr> {
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Alloc::alloc_excess(&mut &*self, layout)
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}
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#[inline]
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unsafe fn realloc_excess(&mut self,
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ptr: *mut u8,
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layout: Layout,
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new_size: usize) -> Result<Excess, AllocErr> {
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Alloc::realloc_excess(&mut &*self, ptr, layout, new_size)
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}
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#[inline]
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unsafe fn grow_in_place(&mut self,
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ptr: *mut u8,
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layout: Layout,
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new_size: usize) -> Result<(), CannotReallocInPlace> {
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Alloc::grow_in_place(&mut &*self, ptr, layout, new_size)
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}
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#[inline]
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unsafe fn shrink_in_place(&mut self,
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ptr: *mut u8,
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layout: Layout,
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new_size: usize) -> Result<(), CannotReallocInPlace> {
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Alloc::shrink_in_place(&mut &*self, ptr, layout, new_size)
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}
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}
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#[cfg(any(windows, unix, target_os = "cloudabi", target_os = "redox"))]
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mod realloc_fallback {
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use core::alloc::{GlobalAlloc, Void, Layout};
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use core::cmp;
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use core::ptr;
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impl super::System {
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pub(crate) unsafe fn realloc_fallback(&self, ptr: *mut Void, old_layout: Layout,
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new_size: usize) -> *mut Void {
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// Docs for GlobalAlloc::realloc require this to be valid:
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let new_layout = Layout::from_size_align_unchecked(new_size, old_layout.align());
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let new_ptr = GlobalAlloc::alloc(self, new_layout);
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if !new_ptr.is_null() {
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let size = cmp::min(old_layout.size(), new_size);
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ptr::copy_nonoverlapping(ptr as *mut u8, new_ptr as *mut u8, size);
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GlobalAlloc::dealloc(self, ptr, old_layout);
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}
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new_ptr
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}
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}
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}
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macro_rules! alloc_methods_based_on_global_alloc {
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() => {
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#[inline]
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unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
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GlobalAlloc::alloc(*self, layout).into()
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}
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#[inline]
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unsafe fn alloc_zeroed(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
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GlobalAlloc::alloc_zeroed(*self, layout).into()
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}
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#[inline]
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unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
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GlobalAlloc::dealloc(*self, ptr as *mut Void, layout)
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}
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#[inline]
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unsafe fn realloc(&mut self,
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ptr: *mut u8,
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old_layout: Layout,
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new_size: usize) -> Result<*mut u8, AllocErr> {
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GlobalAlloc::realloc(*self, ptr as *mut Void, old_layout, new_size).into()
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}
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}
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}
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#[cfg(any(unix, target_os = "cloudabi", target_os = "redox"))]
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mod platform {
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extern crate libc;
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use core::ptr;
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use MIN_ALIGN;
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use System;
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use core::alloc::{GlobalAlloc, Alloc, AllocErr, Layout, Void};
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#[unstable(feature = "allocator_api", issue = "32838")]
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unsafe impl GlobalAlloc for System {
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#[inline]
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unsafe fn alloc(&self, layout: Layout) -> *mut Void {
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if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
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libc::malloc(layout.size()) as *mut Void
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} else {
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#[cfg(target_os = "macos")]
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{
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if layout.align() > (1 << 31) {
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// FIXME: use Void::null_mut https://github.com/rust-lang/rust/issues/49659
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return 0 as *mut Void
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}
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}
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aligned_malloc(&layout)
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}
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}
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#[inline]
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unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut Void {
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if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
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libc::calloc(layout.size(), 1) as *mut Void
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} else {
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let ptr = self.alloc(layout.clone());
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if !ptr.is_null() {
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ptr::write_bytes(ptr as *mut u8, 0, layout.size());
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}
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ptr
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}
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}
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#[inline]
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unsafe fn dealloc(&self, ptr: *mut Void, _layout: Layout) {
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libc::free(ptr as *mut libc::c_void)
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}
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#[inline]
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unsafe fn realloc(&self, ptr: *mut Void, old_layout: Layout, new_size: usize) -> *mut Void {
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let align = old_layout.align();
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if align <= MIN_ALIGN && align <= new_size {
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libc::realloc(ptr as *mut libc::c_void, new_size) as *mut Void
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} else {
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self.realloc_fallback(ptr, old_layout, new_size)
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}
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}
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}
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#[unstable(feature = "allocator_api", issue = "32838")]
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unsafe impl<'a> Alloc for &'a System {
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alloc_methods_based_on_global_alloc!();
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fn oom(&mut self) -> ! {
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use core::fmt::{self, Write};
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// Print a message to stderr before aborting to assist with
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// debugging. It is critical that this code does not allocate any
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// memory since we are in an OOM situation. Any errors are ignored
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// while printing since there's nothing we can do about them and we
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// are about to exit anyways.
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drop(writeln!(Stderr, "fatal runtime error: {}", AllocErr));
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unsafe {
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::core::intrinsics::abort();
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}
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struct Stderr;
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impl Write for Stderr {
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#[cfg(target_os = "cloudabi")]
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fn write_str(&mut self, _: &str) -> fmt::Result {
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// CloudABI does not have any reserved file descriptor
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// numbers. We should not attempt to write to file
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// descriptor #2, as it may be associated with any kind of
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// resource.
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Ok(())
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}
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#[cfg(not(target_os = "cloudabi"))]
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fn write_str(&mut self, s: &str) -> fmt::Result {
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unsafe {
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libc::write(libc::STDERR_FILENO,
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s.as_ptr() as *const libc::c_void,
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s.len());
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}
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Ok(())
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}
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}
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}
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}
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#[cfg(any(target_os = "android", target_os = "redox", target_os = "solaris"))]
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#[inline]
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unsafe fn aligned_malloc(layout: &Layout) -> *mut Void {
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// On android we currently target API level 9 which unfortunately
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// doesn't have the `posix_memalign` API used below. Instead we use
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// `memalign`, but this unfortunately has the property on some systems
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// where the memory returned cannot be deallocated by `free`!
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//
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// Upon closer inspection, however, this appears to work just fine with
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// Android, so for this platform we should be fine to call `memalign`
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// (which is present in API level 9). Some helpful references could
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// possibly be chromium using memalign [1], attempts at documenting that
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// memalign + free is ok [2] [3], or the current source of chromium
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// which still uses memalign on android [4].
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//
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// [1]: https://codereview.chromium.org/10796020/
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// [2]: https://code.google.com/p/android/issues/detail?id=35391
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// [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
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// [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
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// /memory/aligned_memory.cc
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libc::memalign(layout.align(), layout.size()) as *mut Void
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}
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#[cfg(not(any(target_os = "android", target_os = "redox", target_os = "solaris")))]
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#[inline]
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unsafe fn aligned_malloc(layout: &Layout) -> *mut Void {
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let mut out = ptr::null_mut();
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let ret = libc::posix_memalign(&mut out, layout.align(), layout.size());
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if ret != 0 {
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// FIXME: use Void::null_mut https://github.com/rust-lang/rust/issues/49659
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0 as *mut Void
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} else {
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out as *mut Void
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}
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}
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}
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#[cfg(windows)]
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#[allow(bad_style)]
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mod platform {
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use core::ptr;
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use MIN_ALIGN;
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use System;
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use core::alloc::{GlobalAlloc, Alloc, Void, AllocErr, Layout, CannotReallocInPlace};
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type LPVOID = *mut u8;
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type HANDLE = LPVOID;
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type SIZE_T = usize;
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type DWORD = u32;
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type BOOL = i32;
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type LPDWORD = *mut DWORD;
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type LPOVERLAPPED = *mut u8;
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const STD_ERROR_HANDLE: DWORD = -12i32 as DWORD;
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extern "system" {
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fn GetProcessHeap() -> HANDLE;
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fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
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fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
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fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
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fn GetLastError() -> DWORD;
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fn WriteFile(hFile: HANDLE,
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lpBuffer: LPVOID,
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nNumberOfBytesToWrite: DWORD,
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lpNumberOfBytesWritten: LPDWORD,
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lpOverlapped: LPOVERLAPPED)
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-> BOOL;
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fn GetStdHandle(which: DWORD) -> HANDLE;
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}
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#[repr(C)]
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struct Header(*mut u8);
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const HEAP_ZERO_MEMORY: DWORD = 0x00000008;
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const HEAP_REALLOC_IN_PLACE_ONLY: DWORD = 0x00000010;
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unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
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&mut *(ptr as *mut Header).offset(-1)
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}
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unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
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let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
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*get_header(aligned) = Header(ptr);
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aligned
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}
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#[inline]
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unsafe fn allocate_with_flags(layout: Layout, flags: DWORD) -> *mut Void {
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let ptr = if layout.align() <= MIN_ALIGN {
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HeapAlloc(GetProcessHeap(), flags, layout.size())
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} else {
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let size = layout.size() + layout.align();
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let ptr = HeapAlloc(GetProcessHeap(), flags, size);
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if ptr.is_null() {
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ptr
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} else {
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align_ptr(ptr, layout.align())
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}
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};
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ptr as *mut Void
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}
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#[unstable(feature = "allocator_api", issue = "32838")]
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unsafe impl GlobalAlloc for System {
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#[inline]
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unsafe fn alloc(&self, layout: Layout) -> *mut Void {
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allocate_with_flags(layout, 0)
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}
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#[inline]
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unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut Void {
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allocate_with_flags(layout, HEAP_ZERO_MEMORY)
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}
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#[inline]
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unsafe fn dealloc(&self, ptr: *mut Void, layout: Layout) {
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if layout.align() <= MIN_ALIGN {
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let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID);
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debug_assert!(err != 0, "Failed to free heap memory: {}",
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GetLastError());
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} else {
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let header = get_header(ptr as *mut u8);
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let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
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debug_assert!(err != 0, "Failed to free heap memory: {}",
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GetLastError());
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}
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}
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#[inline]
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unsafe fn realloc(&self, ptr: *mut Void, old_layout: Layout, new_size: usize) -> *mut Void {
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let align = old_layout.align();
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if align <= MIN_ALIGN {
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HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, new_size) as *mut Void
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} else {
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self.realloc_fallback(ptr, old_layout, new_size)
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}
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}
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}
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#[unstable(feature = "allocator_api", issue = "32838")]
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unsafe impl<'a> Alloc for &'a System {
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alloc_methods_based_on_global_alloc!();
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#[inline]
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unsafe fn grow_in_place(&mut self,
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ptr: *mut u8,
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layout: Layout,
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new_size: usize) -> Result<(), CannotReallocInPlace> {
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self.shrink_in_place(ptr, layout, new_size)
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}
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#[inline]
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unsafe fn shrink_in_place(&mut self,
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ptr: *mut u8,
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layout: Layout,
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new_size: usize) -> Result<(), CannotReallocInPlace> {
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let new = if layout.align() <= MIN_ALIGN {
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HeapReAlloc(GetProcessHeap(),
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HEAP_REALLOC_IN_PLACE_ONLY,
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ptr as LPVOID,
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new_size)
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} else {
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let header = get_header(ptr);
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HeapReAlloc(GetProcessHeap(),
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HEAP_REALLOC_IN_PLACE_ONLY,
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header.0 as LPVOID,
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new_size + layout.align())
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};
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if new.is_null() {
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Err(CannotReallocInPlace)
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} else {
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Ok(())
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}
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}
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|
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fn oom(&mut self) -> ! {
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use core::fmt::{self, Write};
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|
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// Same as with unix we ignore all errors here
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drop(writeln!(Stderr, "fatal runtime error: {}", AllocErr));
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unsafe {
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::core::intrinsics::abort();
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}
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struct Stderr;
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impl Write for Stderr {
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fn write_str(&mut self, s: &str) -> fmt::Result {
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unsafe {
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// WriteFile silently fails if it is passed an invalid
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// handle, so there is no need to check the result of
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// GetStdHandle.
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WriteFile(GetStdHandle(STD_ERROR_HANDLE),
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s.as_ptr() as LPVOID,
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s.len() as DWORD,
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ptr::null_mut(),
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ptr::null_mut());
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}
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Ok(())
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}
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}
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}
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}
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}
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|
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// This is an implementation of a global allocator on the wasm32 platform when
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// emscripten is not in use. In that situation there's no actual runtime for us
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// to lean on for allocation, so instead we provide our own!
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//
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// The wasm32 instruction set has two instructions for getting the current
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// amount of memory and growing the amount of memory. These instructions are the
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// foundation on which we're able to build an allocator, so we do so! Note that
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// the instructions are also pretty "global" and this is the "global" allocator
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// after all!
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//
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// The current allocator here is the `dlmalloc` crate which we've got included
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// in the rust-lang/rust repository as a submodule. The crate is a port of
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// dlmalloc.c from C to Rust and is basically just so we can have "pure Rust"
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// for now which is currently technically required (can't link with C yet).
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//
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// The crate itself provides a global allocator which on wasm has no
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// synchronization as there are no threads!
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#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
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mod platform {
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extern crate dlmalloc;
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use core::alloc::{GlobalAlloc, Alloc, AllocErr, Layout, Void};
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use System;
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// No need for synchronization here as wasm is currently single-threaded
|
|
static mut DLMALLOC: dlmalloc::Dlmalloc = dlmalloc::DLMALLOC_INIT;
|
|
|
|
#[unstable(feature = "allocator_api", issue = "32838")]
|
|
unsafe impl GlobalAlloc for System {
|
|
#[inline]
|
|
unsafe fn alloc(&self, layout: Layout) -> *mut Void {
|
|
DLMALLOC.malloc(layout.size(), layout.align()) as *mut Void
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut Void {
|
|
DLMALLOC.calloc(layout.size(), layout.align()) as *mut Void
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn dealloc(&self, ptr: *mut Void, layout: Layout) {
|
|
DLMALLOC.free(ptr as *mut u8, layout.size(), layout.align())
|
|
}
|
|
|
|
#[inline]
|
|
unsafe fn realloc(&self, ptr: *mut Void, layout: Layout, new_size: usize) -> *mut Void {
|
|
DLMALLOC.realloc(ptr as *mut u8, layout.size(), layout.align(), new_size) as *mut Void
|
|
}
|
|
}
|
|
|
|
#[unstable(feature = "allocator_api", issue = "32838")]
|
|
unsafe impl<'a> Alloc for &'a System {
|
|
alloc_methods_based_on_global_alloc!();
|
|
}
|
|
}
|