rust/src/liballoc/heap.rs
2015-03-23 12:21:53 -04:00

412 lines
13 KiB
Rust

// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// FIXME: #13996: mark the `allocate` and `reallocate` return value as `noalias`
/// Return a pointer to `size` bytes of memory aligned to `align`.
///
/// On failure, return a null pointer.
///
/// Behavior is undefined if the requested size is 0 or the alignment is not a
/// power of 2. The alignment must be no larger than the largest supported page
/// size on the platform.
#[inline]
pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
imp::allocate(size, align)
}
/// Resize the allocation referenced by `ptr` to `size` bytes.
///
/// On failure, return a null pointer and leave the original allocation intact.
///
/// If the allocation was relocated, the memory at the passed-in pointer is
/// undefined after the call.
///
/// Behavior is undefined if the requested size is 0 or the alignment is not a
/// power of 2. The alignment must be no larger than the largest supported page
/// size on the platform.
///
/// The `old_size` and `align` parameters are the parameters that were used to
/// create the allocation referenced by `ptr`. The `old_size` parameter may be
/// any value in range_inclusive(requested_size, usable_size).
#[inline]
pub unsafe fn reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8 {
imp::reallocate(ptr, old_size, size, align)
}
/// Resize the allocation referenced by `ptr` to `size` bytes.
///
/// If the operation succeeds, it returns `usable_size(size, align)` and if it
/// fails (or is a no-op) it returns `usable_size(old_size, align)`.
///
/// Behavior is undefined if the requested size is 0 or the alignment is not a
/// power of 2. The alignment must be no larger than the largest supported page
/// size on the platform.
///
/// The `old_size` and `align` parameters are the parameters that were used to
/// create the allocation referenced by `ptr`. The `old_size` parameter may be
/// any value in range_inclusive(requested_size, usable_size).
#[inline]
pub unsafe fn reallocate_inplace(ptr: *mut u8, old_size: usize, size: usize,
align: usize) -> usize {
imp::reallocate_inplace(ptr, old_size, size, align)
}
/// Deallocates the memory referenced by `ptr`.
///
/// The `ptr` parameter must not be null.
///
/// The `old_size` and `align` parameters are the parameters that were used to
/// create the allocation referenced by `ptr`. The `old_size` parameter may be
/// any value in range_inclusive(requested_size, usable_size).
#[inline]
pub unsafe fn deallocate(ptr: *mut u8, old_size: usize, align: usize) {
imp::deallocate(ptr, old_size, align)
}
/// Returns the usable size of an allocation created with the specified the
/// `size` and `align`.
#[inline]
pub fn usable_size(size: usize, align: usize) -> usize {
imp::usable_size(size, align)
}
/// Prints implementation-defined allocator statistics.
///
/// These statistics may be inconsistent if other threads use the allocator
/// during the call.
#[unstable(feature = "alloc")]
pub fn stats_print() {
imp::stats_print();
}
/// An arbitrary non-null address to represent zero-size allocations.
///
/// This preserves the non-null invariant for types like `Box<T>`. The address may overlap with
/// non-zero-size memory allocations.
pub const EMPTY: *mut () = 0x1 as *mut ();
/// The allocator for unique pointers.
#[cfg(not(test))]
#[lang="exchange_malloc"]
#[inline]
unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
if size == 0 {
EMPTY as *mut u8
} else {
let ptr = allocate(size, align);
if ptr.is_null() { ::oom() }
ptr
}
}
#[cfg(not(test))]
#[lang="exchange_free"]
#[inline]
unsafe fn exchange_free(ptr: *mut u8, old_size: usize, align: usize) {
deallocate(ptr, old_size, align);
}
// The minimum alignment guaranteed by the architecture. This value is used to
// add fast paths for low alignment values. In practice, the alignment is a
// constant at the call site and the branch will be optimized out.
#[cfg(all(not(feature = "external_funcs"),
not(feature = "external_crate"),
any(target_arch = "arm",
target_arch = "mips",
target_arch = "mipsel",
target_arch = "powerpc")))]
const MIN_ALIGN: usize = 8;
#[cfg(all(not(feature = "external_funcs"),
not(feature = "external_crate"),
any(target_arch = "x86",
target_arch = "x86_64",
target_arch = "aarch64")))]
const MIN_ALIGN: usize = 16;
#[cfg(feature = "external_funcs")]
mod imp {
extern {
fn rust_allocate(size: usize, align: usize) -> *mut u8;
fn rust_deallocate(ptr: *mut u8, old_size: usize, align: usize);
fn rust_reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8;
fn rust_reallocate_inplace(ptr: *mut u8, old_size: usize, size: usize,
align: usize) -> usize;
fn rust_usable_size(size: usize, align: usize) -> usize;
fn rust_stats_print();
}
#[inline]
pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
rust_allocate(size, align)
}
#[inline]
pub unsafe fn deallocate(ptr: *mut u8, old_size: usize, align: usize) {
rust_deallocate(ptr, old_size, align)
}
#[inline]
pub unsafe fn reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8 {
rust_reallocate(ptr, old_size, size, align)
}
#[inline]
pub unsafe fn reallocate_inplace(ptr: *mut u8, old_size: usize, size: usize,
align: usize) -> usize {
rust_reallocate_inplace(ptr, old_size, size, align)
}
#[inline]
pub fn usable_size(size: usize, align: usize) -> usize {
unsafe { rust_usable_size(size, align) }
}
#[inline]
pub fn stats_print() {
unsafe { rust_stats_print() }
}
}
#[cfg(feature = "external_crate")]
mod imp {
extern crate external;
pub use self::external::{allocate, deallocate, reallocate_inplace, reallocate};
pub use self::external::{usable_size, stats_print};
}
#[cfg(all(not(feature = "external_funcs"),
not(feature = "external_crate"),
jemalloc))]
mod imp {
use core::option::Option;
use core::option::Option::None;
use core::ptr::{null_mut, null};
use core::num::Int;
use libc::{c_char, c_int, c_void, size_t};
use super::MIN_ALIGN;
#[link(name = "jemalloc", kind = "static")]
#[cfg(not(test))]
extern {}
extern {
#[allocator]
fn je_mallocx(size: size_t, flags: c_int) -> *mut c_void;
fn je_rallocx(ptr: *mut c_void, size: size_t, flags: c_int) -> *mut c_void;
fn je_xallocx(ptr: *mut c_void, size: size_t, extra: size_t, flags: c_int) -> size_t;
fn je_sdallocx(ptr: *mut c_void, size: size_t, flags: c_int);
fn je_nallocx(size: size_t, flags: c_int) -> size_t;
fn je_malloc_stats_print(write_cb: Option<extern "C" fn(cbopaque: *mut c_void,
*const c_char)>,
cbopaque: *mut c_void,
opts: *const c_char);
}
// -lpthread needs to occur after -ljemalloc, the earlier argument isn't enough
#[cfg(all(not(windows), not(target_os = "android")))]
#[link(name = "pthread")]
extern {}
// MALLOCX_ALIGN(a) macro
#[inline(always)]
fn mallocx_align(a: usize) -> c_int { a.trailing_zeros() as c_int }
#[inline(always)]
fn align_to_flags(align: usize) -> c_int {
if align <= MIN_ALIGN { 0 } else { mallocx_align(align) }
}
#[inline]
pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
let flags = align_to_flags(align);
je_mallocx(size as size_t, flags) as *mut u8
}
#[inline]
pub unsafe fn reallocate(ptr: *mut u8, _old_size: usize, size: usize, align: usize) -> *mut u8 {
let flags = align_to_flags(align);
je_rallocx(ptr as *mut c_void, size as size_t, flags) as *mut u8
}
#[inline]
pub unsafe fn reallocate_inplace(ptr: *mut u8, _old_size: usize, size: usize,
align: usize) -> usize {
let flags = align_to_flags(align);
je_xallocx(ptr as *mut c_void, size as size_t, 0, flags) as usize
}
#[inline]
pub unsafe fn deallocate(ptr: *mut u8, old_size: usize, align: usize) {
let flags = align_to_flags(align);
je_sdallocx(ptr as *mut c_void, old_size as size_t, flags)
}
#[inline]
pub fn usable_size(size: usize, align: usize) -> usize {
let flags = align_to_flags(align);
unsafe { je_nallocx(size as size_t, flags) as usize }
}
pub fn stats_print() {
unsafe {
je_malloc_stats_print(None, null_mut(), null())
}
}
}
#[cfg(all(not(feature = "external_funcs"),
not(feature = "external_crate"),
not(jemalloc),
unix))]
mod imp {
use core::cmp;
use core::ptr;
use libc;
use super::MIN_ALIGN;
extern {
fn posix_memalign(memptr: *mut *mut libc::c_void,
align: libc::size_t,
size: libc::size_t) -> libc::c_int;
}
#[inline]
pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
if align <= MIN_ALIGN {
libc::malloc(size as libc::size_t) as *mut u8
} else {
let mut out = ptr::null_mut();
let ret = posix_memalign(&mut out,
align as libc::size_t,
size as libc::size_t);
if ret != 0 {
ptr::null_mut()
} else {
out as *mut u8
}
}
}
#[inline]
pub unsafe fn reallocate(ptr: *mut u8, old_size: usize, size: usize, align: usize) -> *mut u8 {
if align <= MIN_ALIGN {
libc::realloc(ptr as *mut libc::c_void, size as libc::size_t) as *mut u8
} else {
let new_ptr = allocate(size, align);
ptr::copy(new_ptr, ptr, cmp::min(size, old_size));
deallocate(ptr, old_size, align);
new_ptr
}
}
#[inline]
pub unsafe fn reallocate_inplace(_ptr: *mut u8, old_size: usize, _size: usize,
_align: usize) -> usize {
old_size
}
#[inline]
pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, _align: usize) {
libc::free(ptr as *mut libc::c_void)
}
#[inline]
pub fn usable_size(size: usize, _align: usize) -> usize {
size
}
pub fn stats_print() {}
}
#[cfg(all(not(feature = "external_funcs"),
not(feature = "external_crate"),
not(jemalloc),
windows))]
mod imp {
use libc::{c_void, size_t};
use libc;
use super::MIN_ALIGN;
extern {
fn _aligned_malloc(size: size_t, align: size_t) -> *mut c_void;
fn _aligned_realloc(block: *mut c_void, size: size_t,
align: size_t) -> *mut c_void;
fn _aligned_free(ptr: *mut c_void);
}
#[inline]
pub unsafe fn allocate(size: usize, align: usize) -> *mut u8 {
if align <= MIN_ALIGN {
libc::malloc(size as size_t) as *mut u8
} else {
_aligned_malloc(size as size_t, align as size_t) as *mut u8
}
}
#[inline]
pub unsafe fn reallocate(ptr: *mut u8, _old_size: usize, size: usize, align: usize) -> *mut u8 {
if align <= MIN_ALIGN {
libc::realloc(ptr as *mut c_void, size as size_t) as *mut u8
} else {
_aligned_realloc(ptr as *mut c_void, size as size_t, align as size_t) as *mut u8
}
}
#[inline]
pub unsafe fn reallocate_inplace(_ptr: *mut u8, old_size: usize, _size: usize,
_align: usize) -> usize {
old_size
}
#[inline]
pub unsafe fn deallocate(ptr: *mut u8, _old_size: usize, align: usize) {
if align <= MIN_ALIGN {
libc::free(ptr as *mut libc::c_void)
} else {
_aligned_free(ptr as *mut c_void)
}
}
#[inline]
pub fn usable_size(size: usize, _align: usize) -> usize {
size
}
pub fn stats_print() {}
}
#[cfg(test)]
mod test {
extern crate test;
use self::test::Bencher;
use boxed::Box;
use heap;
#[test]
fn basic_reallocate_inplace_noop() {
unsafe {
let size = 4000;
let ptr = heap::allocate(size, 8);
if ptr.is_null() { ::oom() }
let ret = heap::reallocate_inplace(ptr, size, size, 8);
heap::deallocate(ptr, size, 8);
assert_eq!(ret, heap::usable_size(size, 8));
}
}
#[bench]
fn alloc_owned_small(b: &mut Bencher) {
b.iter(|| {
let _: Box<_> = box 10;
})
}
}