std: Make atomics immutable. #11583

In Rust, the strongest guarantee that `&mut` provides is that the memory
pointed to is *not aliased*, whereas `&`'s guarantees are much weaker:
that the value can be aliased, and may be mutated under proper precautions
(interior mutability).

Our atomics though use `&mut` for mutation even while creating multiple
aliases, so this changes them to use 'interior mutability', mutating
through immutable references.
This commit is contained in:
Brian Anderson 2014-02-17 01:37:26 -08:00 committed by Alex Crichton
parent c01e2f05a3
commit f3fef9a649
7 changed files with 1093 additions and 71 deletions

View File

@ -4012,7 +4012,7 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &ast::ForeignItem) {
//We only care about the operation here
match *split.get(1) {
"cxchg" => (1, vec!(ty::mk_mut_rptr(tcx,
"cxchg" => (1, vec!(ty::mk_imm_rptr(tcx,
ty::ReLateBound(it.id, ty::BrAnon(0)),
param(ccx, 0)),
param(ccx, 0),
@ -4025,7 +4025,7 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &ast::ForeignItem) {
param(ccx, 0)),
"store" => (1,
vec!(
ty::mk_mut_rptr(tcx, ty::ReLateBound(it.id, ty::BrAnon(0)),
ty::mk_imm_rptr(tcx, ty::ReLateBound(it.id, ty::BrAnon(0)),
param(ccx, 0)),
param(ccx, 0)
),
@ -4033,7 +4033,7 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &ast::ForeignItem) {
"xchg" | "xadd" | "xsub" | "and" | "nand" | "or" | "xor" | "max" |
"min" | "umax" | "umin" => {
(1, vec!(ty::mk_mut_rptr(tcx,
(1, vec!(ty::mk_imm_rptr(tcx,
ty::ReLateBound(it.id, ty::BrAnon(0)),
param(ccx, 0)), param(ccx, 0) ),
param(ccx, 0))

View File

@ -164,6 +164,7 @@ pub trait TyVisitor {
fn visit_self(&mut self) -> bool;
}
#[cfg(stage0)]
extern "rust-intrinsic" {
pub fn atomic_cxchg<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg_acq<T>(dst: &mut T, old: T, src: T) -> T;
@ -244,6 +245,93 @@ extern "rust-intrinsic" {
pub fn atomic_umax_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_umax_acqrel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_umax_relaxed<T>(dst: &mut T, src: T) -> T;
}
#[cfg(not(stage0))]
extern "rust-intrinsic" {
pub fn atomic_cxchg<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_acq<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_rel<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_acqrel<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_relaxed<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_load<T>(src: &T) -> T;
pub fn atomic_load_acq<T>(src: &T) -> T;
pub fn atomic_load_relaxed<T>(src: &T) -> T;
pub fn atomic_store<T>(dst: &T, val: T);
pub fn atomic_store_rel<T>(dst: &T, val: T);
pub fn atomic_store_relaxed<T>(dst: &T, val: T);
pub fn atomic_xchg<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_and<T>(dst: &T, src: T) -> T;
pub fn atomic_and_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_and_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_and_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_and_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_nand<T>(dst: &T, src: T) -> T;
pub fn atomic_nand_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_nand_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_nand_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_nand_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_or<T>(dst: &T, src: T) -> T;
pub fn atomic_or_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_or_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_or_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_or_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_xor<T>(dst: &T, src: T) -> T;
pub fn atomic_xor_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xor_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xor_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_xor_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_max<T>(dst: &T, src: T) -> T;
pub fn atomic_max_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_max_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_max_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_max_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_min<T>(dst: &T, src: T) -> T;
pub fn atomic_min_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_min_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_min_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_min_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_umin<T>(dst: &T, src: T) -> T;
pub fn atomic_umin_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_umin_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_umin_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_umin_relaxed<T>(dst: &T, src: T) -> T;
pub fn atomic_umax<T>(dst: &T, src: T) -> T;
pub fn atomic_umax_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_umax_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_umax_acqrel<T>(dst: &T, src: T) -> T;
pub fn atomic_umax_relaxed<T>(dst: &T, src: T) -> T;
}
extern "rust-intrinsic" {
pub fn atomic_fence();
pub fn atomic_fence_acq();

View File

@ -222,7 +222,7 @@ impl AtomicBool {
/// Store the value
#[inline]
pub fn store(&mut self, val: bool, order: Ordering) {
pub fn store(&self, val: bool, order: Ordering) {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_store(&mut *self.v.get(), val, order); }
@ -230,7 +230,7 @@ impl AtomicBool {
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: bool, order: Ordering) -> bool {
pub fn swap(&self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_swap(&mut *self.v.get(), val, order) > 0 }
@ -282,7 +282,7 @@ impl AtomicBool {
/// }
/// ```
#[inline]
pub fn compare_and_swap(&mut self, old: bool, new: bool, order: Ordering) -> bool {
pub fn compare_and_swap(&self, old: bool, new: bool, order: Ordering) -> bool {
let old = if old { UINT_TRUE } else { 0 };
let new = if new { UINT_TRUE } else { 0 };
@ -313,7 +313,7 @@ impl AtomicBool {
/// assert_eq!(false, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_and(&mut self, val: bool, order: Ordering) -> bool {
pub fn fetch_and(&self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_and(&mut *self.v.get(), val, order) > 0 }
@ -344,7 +344,7 @@ impl AtomicBool {
/// assert_eq!(true, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_nand(&mut self, val: bool, order: Ordering) -> bool {
pub fn fetch_nand(&self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_nand(&mut *self.v.get(), val, order) > 0 }
@ -374,7 +374,7 @@ impl AtomicBool {
/// assert_eq!(false, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_or(&mut self, val: bool, order: Ordering) -> bool {
pub fn fetch_or(&self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_or(&mut *self.v.get(), val, order) > 0 }
@ -404,7 +404,7 @@ impl AtomicBool {
/// assert_eq!(false, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_xor(&mut self, val: bool, order: Ordering) -> bool {
pub fn fetch_xor(&self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_xor(&mut *self.v.get(), val, order) > 0 }
@ -425,13 +425,13 @@ impl AtomicInt {
/// Store the value
#[inline]
pub fn store(&mut self, val: int, order: Ordering) {
pub fn store(&self, val: int, order: Ordering) {
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: int, order: Ordering) -> int {
pub fn swap(&self, val: int, order: Ordering) -> int {
unsafe { atomic_swap(&mut *self.v.get(), val, order) }
}
@ -441,7 +441,7 @@ impl AtomicInt {
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
#[inline]
pub fn compare_and_swap(&mut self, old: int, new: int, order: Ordering) -> int {
pub fn compare_and_swap(&self, old: int, new: int, order: Ordering) -> int {
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) }
}
@ -457,7 +457,7 @@ impl AtomicInt {
/// assert_eq!(10, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_add(&mut self, val: int, order: Ordering) -> int {
pub fn fetch_add(&self, val: int, order: Ordering) -> int {
unsafe { atomic_add(&mut *self.v.get(), val, order) }
}
@ -473,7 +473,7 @@ impl AtomicInt {
/// assert_eq!(-10, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_sub(&mut self, val: int, order: Ordering) -> int {
pub fn fetch_sub(&self, val: int, order: Ordering) -> int {
unsafe { atomic_sub(&mut *self.v.get(), val, order) }
}
}
@ -493,27 +493,27 @@ impl AtomicU64 {
}
#[inline]
pub fn store(&mut self, val: u64, order: Ordering) {
pub fn store(&self, val: u64, order: Ordering) {
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
#[inline]
pub fn swap(&mut self, val: u64, order: Ordering) -> u64 {
pub fn swap(&self, val: u64, order: Ordering) -> u64 {
unsafe { atomic_swap(&mut *self.v.get(), val, order) }
}
#[inline]
pub fn compare_and_swap(&mut self, old: u64, new: u64, order: Ordering) -> u64 {
pub fn compare_and_swap(&self, old: u64, new: u64, order: Ordering) -> u64 {
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) }
}
#[inline]
pub fn fetch_add(&mut self, val: u64, order: Ordering) -> u64 {
pub fn fetch_add(&self, val: u64, order: Ordering) -> u64 {
unsafe { atomic_add(&mut *self.v.get(), val, order) }
}
#[inline]
pub fn fetch_sub(&mut self, val: u64, order: Ordering) -> u64 {
pub fn fetch_sub(&self, val: u64, order: Ordering) -> u64 {
unsafe { atomic_sub(&mut *self.v.get(), val, order) }
}
}
@ -532,13 +532,13 @@ impl AtomicUint {
/// Store the value
#[inline]
pub fn store(&mut self, val: uint, order: Ordering) {
pub fn store(&self, val: uint, order: Ordering) {
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: uint, order: Ordering) -> uint {
pub fn swap(&self, val: uint, order: Ordering) -> uint {
unsafe { atomic_swap(&mut *self.v.get(), val, order) }
}
@ -548,7 +548,7 @@ impl AtomicUint {
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
#[inline]
pub fn compare_and_swap(&mut self, old: uint, new: uint, order: Ordering) -> uint {
pub fn compare_and_swap(&self, old: uint, new: uint, order: Ordering) -> uint {
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) }
}
@ -564,7 +564,7 @@ impl AtomicUint {
/// assert_eq!(10, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_add(&mut self, val: uint, order: Ordering) -> uint {
pub fn fetch_add(&self, val: uint, order: Ordering) -> uint {
unsafe { atomic_add(&mut *self.v.get(), val, order) }
}
@ -580,7 +580,7 @@ impl AtomicUint {
/// assert_eq!(0, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_sub(&mut self, val: uint, order: Ordering) -> uint {
pub fn fetch_sub(&self, val: uint, order: Ordering) -> uint {
unsafe { atomic_sub(&mut *self.v.get(), val, order) }
}
}
@ -601,13 +601,13 @@ impl<T> AtomicPtr<T> {
/// Store the value
#[inline]
pub fn store(&mut self, ptr: *mut T, order: Ordering) {
pub fn store(&self, ptr: *mut T, order: Ordering) {
unsafe { atomic_store(&mut *self.p.get(), ptr as uint, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, ptr: *mut T, order: Ordering) -> *mut T {
pub fn swap(&self, ptr: *mut T, order: Ordering) -> *mut T {
unsafe { atomic_swap(&mut *self.p.get(), ptr as uint, order) as *mut T }
}
@ -617,7 +617,7 @@ impl<T> AtomicPtr<T> {
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
#[inline]
pub fn compare_and_swap(&mut self, old: *mut T, new: *mut T, order: Ordering) -> *mut T {
pub fn compare_and_swap(&self, old: *mut T, new: *mut T, order: Ordering) -> *mut T {
unsafe {
atomic_compare_and_swap(&mut *self.p.get(), old as uint,
new as uint, order) as *mut T
@ -636,7 +636,7 @@ impl<T> AtomicOption<T> {
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: ~T, order: Ordering) -> Option<~T> {
pub fn swap(&self, val: ~T, order: Ordering) -> Option<~T> {
unsafe {
let val = cast::transmute(val);
@ -651,7 +651,7 @@ impl<T> AtomicOption<T> {
/// Remove the value, leaving the `AtomicOption` empty.
#[inline]
pub fn take(&mut self, order: Ordering) -> Option<~T> {
pub fn take(&self, order: Ordering) -> Option<~T> {
unsafe { self.swap(cast::transmute(0), order) }
}
@ -661,7 +661,7 @@ impl<T> AtomicOption<T> {
/// the option was already `Some`, returns `Some` of the rejected
/// value.
#[inline]
pub fn fill(&mut self, val: ~T, order: Ordering) -> Option<~T> {
pub fn fill(&self, val: ~T, order: Ordering) -> Option<~T> {
unsafe {
let val = cast::transmute(val);
let expected = cast::transmute(0);
@ -679,7 +679,7 @@ impl<T> AtomicOption<T> {
/// Be careful: The caller must have some external method of ensuring the
/// result does not get invalidated by another task after this returns.
#[inline]
pub fn is_empty(&mut self, order: Ordering) -> bool {
pub fn is_empty(&self, order: Ordering) -> bool {
unsafe { atomic_load(&*self.p.get(), order) as uint == 0 }
}
}
@ -692,7 +692,7 @@ impl<T> Drop for AtomicOption<T> {
}
#[inline]
pub unsafe fn atomic_store<T>(dst: &mut T, val: T, order:Ordering) {
pub unsafe fn atomic_store<T>(dst: &T, val: T, order:Ordering) {
match order {
Release => intrinsics::atomic_store_rel(dst, val),
Relaxed => intrinsics::atomic_store_relaxed(dst, val),
@ -710,7 +710,7 @@ pub unsafe fn atomic_load<T>(dst: &T, order:Ordering) -> T {
}
#[inline]
pub unsafe fn atomic_swap<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_swap<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xchg_acq(dst, val),
Release => intrinsics::atomic_xchg_rel(dst, val),
@ -722,7 +722,7 @@ pub unsafe fn atomic_swap<T>(dst: &mut T, val: T, order: Ordering) -> T {
/// Returns the old value (like __sync_fetch_and_add).
#[inline]
pub unsafe fn atomic_add<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_add<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xadd_acq(dst, val),
Release => intrinsics::atomic_xadd_rel(dst, val),
@ -734,7 +734,7 @@ pub unsafe fn atomic_add<T>(dst: &mut T, val: T, order: Ordering) -> T {
/// Returns the old value (like __sync_fetch_and_sub).
#[inline]
pub unsafe fn atomic_sub<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_sub<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xsub_acq(dst, val),
Release => intrinsics::atomic_xsub_rel(dst, val),
@ -745,7 +745,7 @@ pub unsafe fn atomic_sub<T>(dst: &mut T, val: T, order: Ordering) -> T {
}
#[inline]
pub unsafe fn atomic_compare_and_swap<T>(dst:&mut T, old:T, new:T, order: Ordering) -> T {
pub unsafe fn atomic_compare_and_swap<T>(dst:&T, old:T, new:T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_cxchg_acq(dst, old, new),
Release => intrinsics::atomic_cxchg_rel(dst, old, new),
@ -756,7 +756,7 @@ pub unsafe fn atomic_compare_and_swap<T>(dst:&mut T, old:T, new:T, order: Orderi
}
#[inline]
pub unsafe fn atomic_and<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_and<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_and_acq(dst, val),
Release => intrinsics::atomic_and_rel(dst, val),
@ -767,7 +767,7 @@ pub unsafe fn atomic_and<T>(dst: &mut T, val: T, order: Ordering) -> T {
}
#[inline]
pub unsafe fn atomic_nand<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_nand<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_nand_acq(dst, val),
Release => intrinsics::atomic_nand_rel(dst, val),
@ -779,7 +779,7 @@ pub unsafe fn atomic_nand<T>(dst: &mut T, val: T, order: Ordering) -> T {
#[inline]
pub unsafe fn atomic_or<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_or<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_or_acq(dst, val),
Release => intrinsics::atomic_or_rel(dst, val),
@ -791,7 +791,7 @@ pub unsafe fn atomic_or<T>(dst: &mut T, val: T, order: Ordering) -> T {
#[inline]
pub unsafe fn atomic_xor<T>(dst: &mut T, val: T, order: Ordering) -> T {
pub unsafe fn atomic_xor<T>(dst: &T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xor_acq(dst, val),
Release => intrinsics::atomic_xor_rel(dst, val),
@ -914,16 +914,16 @@ mod test {
fn different_sizes() {
unsafe {
let mut slot = 0u16;
assert_eq!(super::atomic_swap(&mut slot, 1, SeqCst), 0);
assert_eq!(super::atomic_swap(&slot, 1, SeqCst), 0);
let mut slot = 0u8;
assert_eq!(super::atomic_compare_and_swap(&mut slot, 1, 2, SeqCst), 0);
assert_eq!(super::atomic_compare_and_swap(&slot, 1, 2, SeqCst), 0);
let mut slot = 0u32;
assert_eq!(super::atomic_load(&mut slot, SeqCst), 0);
assert_eq!(super::atomic_load(&slot, SeqCst), 0);
let mut slot = 0u64;
super::atomic_store(&mut slot, 2, SeqCst);
super::atomic_store(&slot, 2, SeqCst);
}
}
}

View File

@ -0,0 +1,930 @@
// Copyright 2012-2013 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.
//! Atomic types
//!
//! Atomic types provide primitive shared-memory communication between
//! threads, and are the building blocks of other concurrent
//! types.
//!
//! This module defines atomic versions of a select number of primitive
//! types, including `AtomicBool`, `AtomicInt`, `AtomicUint`, and `AtomicOption`.
//! Atomic types present operations that, when used correctly, synchronize
//! updates between threads.
//!
//! Each method takes an `Ordering` which represents the strength of
//! the memory barrier for that operation. These orderings are the
//! same as [C++11 atomic orderings][1].
//!
//! [1]: http://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync
//!
//! Atomic variables are safe to share between threads (they implement `Share`)
//! but they do not themselves provide the mechanism for sharing. The most
//! common way to share an atomic variable is to put it into an `Arc` (an
//! atomically-reference-counted shared pointer).
//!
//! Most atomic types may be stored in static variables, initialized using
//! the provided static initializers like `INIT_ATOMIC_BOOL`. Atomic statics
//! are often used for lazy global initialization.
//!
//!
//! # Examples
//!
//! A simple spinlock:
//!
//! ```ignore
//! # // FIXME: Needs PR #12430
//! extern crate sync;
//!
//! use sync::Arc;
//! use std::sync::atomics::{AtomicUint, SeqCst};
//! use std::task::deschedule;
//!
//! fn main() {
//! let spinlock = Arc::new(AtomicUint::new(1));
//!
//! let spinlock_clone = spinlock.clone();
//! spawn(proc() {
//! spinlock_clone.store(0, SeqCst);
//! });
//!
//! // Wait for the other task to release the lock
//! while spinlock.load(SeqCst) != 0 {
//! // Since tasks may not be preemptive (if they are green threads)
//! // yield to the scheduler to let the other task run. Low level
//! // concurrent code needs to take into account Rust's two threading
//! // models.
//! deschedule();
//! }
//! }
//! ```
//!
//! Transferring a heap object with `AtomicOption`:
//!
//! ```ignore
//! # // FIXME: Needs PR #12430
//! extern crate sync;
//!
//! use sync::Arc;
//! use std::sync::atomics::{AtomicOption, SeqCst};
//!
//! fn main() {
//! struct BigObject;
//!
//! let shared_big_object = Arc::new(AtomicOption::empty());
//!
//! let shared_big_object_clone = shared_big_object.clone();
//! spawn(proc() {
//! let unwrapped_big_object = shared_big_object_clone.take(SeqCst);
//! if unwrapped_big_object.is_some() {
//! println!("got a big object from another task");
//! } else {
//! println!("other task hasn't sent big object yet");
//! }
//! });
//!
//! shared_big_object.swap(~BigObject, SeqCst);
//! }
//! ```
//!
//! Keep a global count of live tasks:
//!
//! ```
//! use std::sync::atomics::{AtomicUint, SeqCst, INIT_ATOMIC_UINT};
//!
//! static mut GLOBAL_TASK_COUNT: AtomicUint = INIT_ATOMIC_UINT;
//!
//! unsafe {
//! let old_task_count = GLOBAL_TASK_COUNT.fetch_add(1, SeqCst);
//! println!("live tasks: {}", old_task_count + 1);
//! }
//! ```
#[allow(missing_doc)];
use intrinsics;
use cast;
use std::kinds::marker;
use option::{Option,Some,None};
use ops::Drop;
use ty::Unsafe;
/// An atomic boolean type.
pub struct AtomicBool {
priv v: Unsafe<uint>,
priv nopod: marker::NoPod
}
/// A signed atomic integer type, supporting basic atomic arithmetic operations
pub struct AtomicInt {
priv v: Unsafe<int>,
priv nopod: marker::NoPod
}
/// An unsigned atomic integer type, supporting basic atomic arithmetic operations
pub struct AtomicUint {
priv v: Unsafe<uint>,
priv nopod: marker::NoPod
}
/// An unsigned atomic integer type that is forced to be 64-bits. This does not
/// support all operations.
pub struct AtomicU64 {
priv v: Unsafe<u64>,
priv nopod: marker::NoPod
}
/// An unsafe atomic pointer. Only supports basic atomic operations
pub struct AtomicPtr<T> {
priv p: Unsafe<uint>,
priv nopod: marker::NoPod
}
/// An atomic, nullable unique pointer
///
/// This can be used as the concurrency primitive for operations that transfer
/// owned heap objects across tasks.
#[unsafe_no_drop_flag]
pub struct AtomicOption<T> {
priv p: Unsafe<uint>,
}
/// Atomic memory orderings
///
/// Memory orderings limit the ways that both the compiler and CPU may reorder
/// instructions around atomic operations. At its most restrictive,
/// "sequentially consistent" atomics allow neither reads nor writes
/// to be moved either before or after the atomic operation; on the other end
/// "relaxed" atomics allow all reorderings.
///
/// Rust's memory orderings are the same as in C++[1].
///
/// [1]: http://gcc.gnu.org/wiki/Atomic/GCCMM/AtomicSync
pub enum Ordering {
/// No ordering constraints, only atomic operations
Relaxed,
/// When coupled with a store, all previous writes become visible
/// to another thread that performs a load with `Acquire` ordering
/// on the same value
Release,
/// When coupled with a load, all subsequent loads will see data
/// written before a store with `Release` ordering on the same value
/// in another thread
Acquire,
/// When coupled with a load, uses `Acquire` ordering, and with a store
/// `Release` ordering
AcqRel,
/// Like `AcqRel` with the additional guarantee that all threads see all
/// sequentially consistent operations in the same order.
SeqCst
}
/// An `AtomicBool` initialized to `false`
pub static INIT_ATOMIC_BOOL : AtomicBool = AtomicBool { v: Unsafe{value: 0,
marker1: marker::InvariantType},
nopod: marker::NoPod };
/// An `AtomicInt` initialized to `0`
pub static INIT_ATOMIC_INT : AtomicInt = AtomicInt { v: Unsafe{value: 0,
marker1: marker::InvariantType},
nopod: marker::NoPod };
/// An `AtomicUint` initialized to `0`
pub static INIT_ATOMIC_UINT : AtomicUint = AtomicUint { v: Unsafe{value: 0,
marker1: marker::InvariantType},
nopod: marker::NoPod };
/// An `AtomicU64` initialized to `0`
pub static INIT_ATOMIC_U64 : AtomicU64 = AtomicU64 { v: Unsafe{value: 0,
marker1: marker::InvariantType},
nopod: marker::NoPod };
// NB: Needs to be -1 (0b11111111...) to make fetch_nand work correctly
static UINT_TRUE: uint = -1;
impl AtomicBool {
/// Create a new `AtomicBool`
pub fn new(v: bool) -> AtomicBool {
let val = if v { UINT_TRUE } else { 0 };
AtomicBool { v: Unsafe::new(val), nopod: marker::NoPod }
}
/// Load the value
#[inline]
pub fn load(&self, order: Ordering) -> bool {
unsafe { atomic_load(&*self.v.get(), order) > 0 }
}
/// Store the value
#[inline]
pub fn store(&mut self, val: bool, order: Ordering) {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_swap(&mut *self.v.get(), val, order) > 0 }
}
/// If the current value is the same as expected, store a new value
///
/// Compare the current value with `old`; if they are the same then
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
///
/// # Examples
///
/// ```ignore
/// # // FIXME: Needs PR #12430
/// extern crate sync;
///
/// use sync::Arc;
/// use std::sync::atomics::{AtomicBool, SeqCst};
///
/// fn main() {
/// let spinlock = Arc::new(AtomicBool::new(false));
/// let spinlock_clone = spin_lock.clone();
///
/// spawn(proc() {
/// with_lock(&spinlock, || println!("task 1 in lock"));
/// });
///
/// spawn(proc() {
/// with_lock(&spinlock_clone, || println!("task 2 in lock"));
/// });
/// }
///
/// fn with_lock(spinlock: &Arc<AtomicBool>, f: || -> ()) {
/// // CAS loop until we are able to replace `false` with `true`
/// while spinlock.compare_and_swap(false, true, SeqCst) == false {
/// // Since tasks may not be preemptive (if they are green threads)
/// // yield to the scheduler to let the other task run. Low level
/// // concurrent code needs to take into account Rust's two threading
/// // models.
/// deschedule();
/// }
///
/// // Now we have the spinlock
/// f();
///
/// // Release the lock
/// spinlock.store(false);
/// }
/// ```
#[inline]
pub fn compare_and_swap(&mut self, old: bool, new: bool, order: Ordering) -> bool {
let old = if old { UINT_TRUE } else { 0 };
let new = if new { UINT_TRUE } else { 0 };
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) > 0 }
}
/// A logical "and" operation
///
/// Performs a logical "and" operation on the current value and the
/// argument `val`, and sets the new value to the result.
/// Returns the previous value.
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicBool, SeqCst};
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_and(false, SeqCst));
/// assert_eq!(false, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_and(true, SeqCst));
/// assert_eq!(true, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(false);
/// assert_eq!(false, foo.fetch_and(false, SeqCst));
/// assert_eq!(false, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_and(&mut self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_and(&mut *self.v.get(), val, order) > 0 }
}
/// A logical "nand" operation
///
/// Performs a logical "nand" operation on the current value and the
/// argument `val`, and sets the new value to the result.
/// Returns the previous value.
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicBool, SeqCst};
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_nand(false, SeqCst));
/// assert_eq!(true, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_nand(true, SeqCst));
/// assert_eq!(0, foo.load(SeqCst) as int);
/// assert_eq!(false, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(false);
/// assert_eq!(false, foo.fetch_nand(false, SeqCst));
/// assert_eq!(true, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_nand(&mut self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_nand(&mut *self.v.get(), val, order) > 0 }
}
/// A logical "or" operation
///
/// Performs a logical "or" operation on the current value and the
/// argument `val`, and sets the new value to the result.
/// Returns the previous value.
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicBool, SeqCst};
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_or(false, SeqCst));
/// assert_eq!(true, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_or(true, SeqCst));
/// assert_eq!(true, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(false);
/// assert_eq!(false, foo.fetch_or(false, SeqCst));
/// assert_eq!(false, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_or(&mut self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_or(&mut *self.v.get(), val, order) > 0 }
}
/// A logical "xor" operation
///
/// Performs a logical "xor" operation on the current value and the
/// argument `val`, and sets the new value to the result.
/// Returns the previous value.
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicBool, SeqCst};
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_xor(false, SeqCst));
/// assert_eq!(true, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(true);
/// assert_eq!(true, foo.fetch_xor(true, SeqCst));
/// assert_eq!(false, foo.load(SeqCst));
///
/// let mut foo = AtomicBool::new(false);
/// assert_eq!(false, foo.fetch_xor(false, SeqCst));
/// assert_eq!(false, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_xor(&mut self, val: bool, order: Ordering) -> bool {
let val = if val { UINT_TRUE } else { 0 };
unsafe { atomic_xor(&mut *self.v.get(), val, order) > 0 }
}
}
impl AtomicInt {
/// Create a new `AtomicInt`
pub fn new(v: int) -> AtomicInt {
AtomicInt {v: Unsafe::new(v), nopod: marker::NoPod}
}
/// Load the value
#[inline]
pub fn load(&self, order: Ordering) -> int {
unsafe { atomic_load(&*self.v.get(), order) }
}
/// Store the value
#[inline]
pub fn store(&mut self, val: int, order: Ordering) {
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: int, order: Ordering) -> int {
unsafe { atomic_swap(&mut *self.v.get(), val, order) }
}
/// If the current value is the same as expected, store a new value
///
/// Compare the current value with `old`; if they are the same then
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
#[inline]
pub fn compare_and_swap(&mut self, old: int, new: int, order: Ordering) -> int {
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) }
}
/// Add to the current value, returning the previous
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicInt, SeqCst};
///
/// let mut foo = AtomicInt::new(0);
/// assert_eq!(0, foo.fetch_add(10, SeqCst));
/// assert_eq!(10, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_add(&mut self, val: int, order: Ordering) -> int {
unsafe { atomic_add(&mut *self.v.get(), val, order) }
}
/// Subtract from the current value, returning the previous
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicInt, SeqCst};
///
/// let mut foo = AtomicInt::new(0);
/// assert_eq!(0, foo.fetch_sub(10, SeqCst));
/// assert_eq!(-10, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_sub(&mut self, val: int, order: Ordering) -> int {
unsafe { atomic_sub(&mut *self.v.get(), val, order) }
}
}
// temporary workaround
// it causes link failure on MIPS target
// libgcc doesn't implement 64-bit atomic operations for MIPS32
#[cfg(not(target_arch = "mips"))]
impl AtomicU64 {
pub fn new(v: u64) -> AtomicU64 {
AtomicU64 { v: Unsafe::new(v), nopod: marker::NoPod }
}
#[inline]
pub fn load(&self, order: Ordering) -> u64 {
unsafe { atomic_load(&*self.v.get(), order) }
}
#[inline]
pub fn store(&mut self, val: u64, order: Ordering) {
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
#[inline]
pub fn swap(&mut self, val: u64, order: Ordering) -> u64 {
unsafe { atomic_swap(&mut *self.v.get(), val, order) }
}
#[inline]
pub fn compare_and_swap(&mut self, old: u64, new: u64, order: Ordering) -> u64 {
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) }
}
#[inline]
pub fn fetch_add(&mut self, val: u64, order: Ordering) -> u64 {
unsafe { atomic_add(&mut *self.v.get(), val, order) }
}
#[inline]
pub fn fetch_sub(&mut self, val: u64, order: Ordering) -> u64 {
unsafe { atomic_sub(&mut *self.v.get(), val, order) }
}
}
impl AtomicUint {
/// Create a new `AtomicUint`
pub fn new(v: uint) -> AtomicUint {
AtomicUint { v: Unsafe::new(v), nopod: marker::NoPod }
}
/// Load the value
#[inline]
pub fn load(&self, order: Ordering) -> uint {
unsafe { atomic_load(&*self.v.get(), order) }
}
/// Store the value
#[inline]
pub fn store(&mut self, val: uint, order: Ordering) {
unsafe { atomic_store(&mut *self.v.get(), val, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: uint, order: Ordering) -> uint {
unsafe { atomic_swap(&mut *self.v.get(), val, order) }
}
/// If the current value is the same as expected, store a new value
///
/// Compare the current value with `old`; if they are the same then
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
#[inline]
pub fn compare_and_swap(&mut self, old: uint, new: uint, order: Ordering) -> uint {
unsafe { atomic_compare_and_swap(&mut *self.v.get(), old, new, order) }
}
/// Add to the current value, returning the previous
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicUint, SeqCst};
///
/// let mut foo = AtomicUint::new(0);
/// assert_eq!(0, foo.fetch_add(10, SeqCst));
/// assert_eq!(10, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_add(&mut self, val: uint, order: Ordering) -> uint {
unsafe { atomic_add(&mut *self.v.get(), val, order) }
}
/// Subtract from the current value, returning the previous
///
/// # Examples
///
/// ```
/// use std::sync::atomics::{AtomicUint, SeqCst};
///
/// let mut foo = AtomicUint::new(10);
/// assert_eq!(10, foo.fetch_sub(10, SeqCst));
/// assert_eq!(0, foo.load(SeqCst));
/// ```
#[inline]
pub fn fetch_sub(&mut self, val: uint, order: Ordering) -> uint {
unsafe { atomic_sub(&mut *self.v.get(), val, order) }
}
}
impl<T> AtomicPtr<T> {
/// Create a new `AtomicPtr`
pub fn new(p: *mut T) -> AtomicPtr<T> {
AtomicPtr { p: Unsafe::new(p as uint), nopod: marker::NoPod }
}
/// Load the value
#[inline]
pub fn load(&self, order: Ordering) -> *mut T {
unsafe {
atomic_load(&*self.p.get(), order) as *mut T
}
}
/// Store the value
#[inline]
pub fn store(&mut self, ptr: *mut T, order: Ordering) {
unsafe { atomic_store(&mut *self.p.get(), ptr as uint, order); }
}
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, ptr: *mut T, order: Ordering) -> *mut T {
unsafe { atomic_swap(&mut *self.p.get(), ptr as uint, order) as *mut T }
}
/// If the current value is the same as expected, store a new value
///
/// Compare the current value with `old`; if they are the same then
/// replace the current value with `new`. Return the previous value.
/// If the return value is equal to `old` then the value was updated.
#[inline]
pub fn compare_and_swap(&mut self, old: *mut T, new: *mut T, order: Ordering) -> *mut T {
unsafe {
atomic_compare_and_swap(&mut *self.p.get(), old as uint,
new as uint, order) as *mut T
}
}
}
impl<T> AtomicOption<T> {
/// Create a new `AtomicOption`
pub fn new(p: ~T) -> AtomicOption<T> {
unsafe { AtomicOption { p: Unsafe::new(cast::transmute(p)) } }
}
/// Create a new `AtomicOption` that doesn't contain a value
pub fn empty() -> AtomicOption<T> { AtomicOption { p: Unsafe::new(0) } }
/// Store a value, returning the old value
#[inline]
pub fn swap(&mut self, val: ~T, order: Ordering) -> Option<~T> {
unsafe {
let val = cast::transmute(val);
let p = atomic_swap(&mut *self.p.get(), val, order);
if p as uint == 0 {
None
} else {
Some(cast::transmute(p))
}
}
}
/// Remove the value, leaving the `AtomicOption` empty.
#[inline]
pub fn take(&mut self, order: Ordering) -> Option<~T> {
unsafe { self.swap(cast::transmute(0), order) }
}
/// Replace an empty value with a non-empty value.
///
/// Succeeds if the option is `None` and returns `None` if so. If
/// the option was already `Some`, returns `Some` of the rejected
/// value.
#[inline]
pub fn fill(&mut self, val: ~T, order: Ordering) -> Option<~T> {
unsafe {
let val = cast::transmute(val);
let expected = cast::transmute(0);
let oldval = atomic_compare_and_swap(&mut *self.p.get(), expected, val, order);
if oldval == expected {
None
} else {
Some(cast::transmute(val))
}
}
}
/// Returns `true` if the `AtomicOption` is empty.
///
/// Be careful: The caller must have some external method of ensuring the
/// result does not get invalidated by another task after this returns.
#[inline]
pub fn is_empty(&mut self, order: Ordering) -> bool {
unsafe { atomic_load(&*self.p.get(), order) as uint == 0 }
}
}
#[unsafe_destructor]
impl<T> Drop for AtomicOption<T> {
fn drop(&mut self) {
let _ = self.take(SeqCst);
}
}
#[inline]
pub unsafe fn atomic_store<T>(dst: &mut T, val: T, order:Ordering) {
match order {
Release => intrinsics::atomic_store_rel(dst, val),
Relaxed => intrinsics::atomic_store_relaxed(dst, val),
_ => intrinsics::atomic_store(dst, val)
}
}
#[inline]
pub unsafe fn atomic_load<T>(dst: &T, order:Ordering) -> T {
match order {
Acquire => intrinsics::atomic_load_acq(dst),
Relaxed => intrinsics::atomic_load_relaxed(dst),
_ => intrinsics::atomic_load(dst)
}
}
#[inline]
pub unsafe fn atomic_swap<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xchg_acq(dst, val),
Release => intrinsics::atomic_xchg_rel(dst, val),
AcqRel => intrinsics::atomic_xchg_acqrel(dst, val),
Relaxed => intrinsics::atomic_xchg_relaxed(dst, val),
_ => intrinsics::atomic_xchg(dst, val)
}
}
/// Returns the old value (like __sync_fetch_and_add).
#[inline]
pub unsafe fn atomic_add<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xadd_acq(dst, val),
Release => intrinsics::atomic_xadd_rel(dst, val),
AcqRel => intrinsics::atomic_xadd_acqrel(dst, val),
Relaxed => intrinsics::atomic_xadd_relaxed(dst, val),
_ => intrinsics::atomic_xadd(dst, val)
}
}
/// Returns the old value (like __sync_fetch_and_sub).
#[inline]
pub unsafe fn atomic_sub<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xsub_acq(dst, val),
Release => intrinsics::atomic_xsub_rel(dst, val),
AcqRel => intrinsics::atomic_xsub_acqrel(dst, val),
Relaxed => intrinsics::atomic_xsub_relaxed(dst, val),
_ => intrinsics::atomic_xsub(dst, val)
}
}
#[inline]
pub unsafe fn atomic_compare_and_swap<T>(dst:&mut T, old:T, new:T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_cxchg_acq(dst, old, new),
Release => intrinsics::atomic_cxchg_rel(dst, old, new),
AcqRel => intrinsics::atomic_cxchg_acqrel(dst, old, new),
Relaxed => intrinsics::atomic_cxchg_relaxed(dst, old, new),
_ => intrinsics::atomic_cxchg(dst, old, new),
}
}
#[inline]
pub unsafe fn atomic_and<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_and_acq(dst, val),
Release => intrinsics::atomic_and_rel(dst, val),
AcqRel => intrinsics::atomic_and_acqrel(dst, val),
Relaxed => intrinsics::atomic_and_relaxed(dst, val),
_ => intrinsics::atomic_and(dst, val)
}
}
#[inline]
pub unsafe fn atomic_nand<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_nand_acq(dst, val),
Release => intrinsics::atomic_nand_rel(dst, val),
AcqRel => intrinsics::atomic_nand_acqrel(dst, val),
Relaxed => intrinsics::atomic_nand_relaxed(dst, val),
_ => intrinsics::atomic_nand(dst, val)
}
}
#[inline]
pub unsafe fn atomic_or<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_or_acq(dst, val),
Release => intrinsics::atomic_or_rel(dst, val),
AcqRel => intrinsics::atomic_or_acqrel(dst, val),
Relaxed => intrinsics::atomic_or_relaxed(dst, val),
_ => intrinsics::atomic_or(dst, val)
}
}
#[inline]
pub unsafe fn atomic_xor<T>(dst: &mut T, val: T, order: Ordering) -> T {
match order {
Acquire => intrinsics::atomic_xor_acq(dst, val),
Release => intrinsics::atomic_xor_rel(dst, val),
AcqRel => intrinsics::atomic_xor_acqrel(dst, val),
Relaxed => intrinsics::atomic_xor_relaxed(dst, val),
_ => intrinsics::atomic_xor(dst, val)
}
}
/// An atomic fence.
///
/// A fence 'A' which has `Release` ordering semantics, synchronizes with a
/// fence 'B' with (at least) `Acquire` semantics, if and only if there exists
/// atomic operations X and Y, both operating on some atomic object 'M' such
/// that A is sequenced before X, Y is synchronized before B and Y observers
/// the change to M. This provides a happens-before dependence between A and B.
///
/// Atomic operations with `Release` or `Acquire` semantics can also synchronize
/// with a fence.
///
/// A fence with has `SeqCst` ordering, in addition to having both `Acquire` and
/// `Release` semantics, participates in the global program order of the other
/// `SeqCst` operations and/or fences.
///
/// Accepts `Acquire`, `Release`, `AcqRel` and `SeqCst` orderings.
///
/// # Failure
///
/// Fails if `order` is `Relaxed`
#[inline]
pub fn fence(order: Ordering) {
unsafe {
match order {
Acquire => intrinsics::atomic_fence_acq(),
Release => intrinsics::atomic_fence_rel(),
AcqRel => intrinsics::atomic_fence_acqrel(),
SeqCst => intrinsics::atomic_fence(),
Relaxed => fail!("there is no such thing as a relaxed fence")
}
}
}
#[cfg(test)]
mod test {
use option::*;
use super::*;
#[test]
fn bool_() {
let mut a = AtomicBool::new(false);
assert_eq!(a.compare_and_swap(false, true, SeqCst), false);
assert_eq!(a.compare_and_swap(false, true, SeqCst), true);
a.store(false, SeqCst);
assert_eq!(a.compare_and_swap(false, true, SeqCst), false);
}
#[test]
fn option_empty() {
let mut option: AtomicOption<()> = AtomicOption::empty();
assert!(option.is_empty(SeqCst));
}
#[test]
fn option_swap() {
let mut p = AtomicOption::new(~1);
let a = ~2;
let b = p.swap(a, SeqCst);
assert_eq!(b, Some(~1));
assert_eq!(p.take(SeqCst), Some(~2));
}
#[test]
fn option_take() {
let mut p = AtomicOption::new(~1);
assert_eq!(p.take(SeqCst), Some(~1));
assert_eq!(p.take(SeqCst), None);
let p2 = ~2;
p.swap(p2, SeqCst);
assert_eq!(p.take(SeqCst), Some(~2));
}
#[test]
fn option_fill() {
let mut p = AtomicOption::new(~1);
assert!(p.fill(~2, SeqCst).is_some()); // should fail; shouldn't leak!
assert_eq!(p.take(SeqCst), Some(~1));
assert!(p.fill(~2, SeqCst).is_none()); // shouldn't fail
assert_eq!(p.take(SeqCst), Some(~2));
}
#[test]
fn bool_and() {
let mut a = AtomicBool::new(true);
assert_eq!(a.fetch_and(false, SeqCst),true);
assert_eq!(a.load(SeqCst),false);
}
static mut S_BOOL : AtomicBool = INIT_ATOMIC_BOOL;
static mut S_INT : AtomicInt = INIT_ATOMIC_INT;
static mut S_UINT : AtomicUint = INIT_ATOMIC_UINT;
#[test]
fn static_init() {
unsafe {
assert!(!S_BOOL.load(SeqCst));
assert!(S_INT.load(SeqCst) == 0);
assert!(S_UINT.load(SeqCst) == 0);
}
}
#[test]
fn different_sizes() {
unsafe {
let mut slot = 0u16;
assert_eq!(super::atomic_swap(&mut slot, 1, SeqCst), 0);
let mut slot = 0u8;
assert_eq!(super::atomic_compare_and_swap(&mut slot, 1, 2, SeqCst), 0);
let mut slot = 0u32;
assert_eq!(super::atomic_load(&mut slot, SeqCst), 0);
let mut slot = 0u64;
super::atomic_store(&mut slot, 2, SeqCst);
}
}
}

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@ -16,6 +16,10 @@
//! other types of concurrent primitives.
pub mod arc;
#[cfg(stage0)]
#[path = "atomics_stage0.rs"]
pub mod atomics;
#[cfg(not(stage0))]
pub mod atomics;
pub mod deque;
pub mod mpmc_bounded_queue;

View File

@ -10,21 +10,21 @@
pub mod rusti {
extern "rust-intrinsic" {
pub fn atomic_cxchg<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg_acq<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg_rel<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_acq<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_rel<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_xchg<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xchg_acq<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xchg_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xchg<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xadd_acq<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xadd_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xadd<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xsub_acq<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xsub_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xsub<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_rel<T>(dst: &T, src: T) -> T;
}
}

View File

@ -10,27 +10,27 @@
mod rusti {
extern "rust-intrinsic" {
pub fn atomic_cxchg<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg_acq<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg_rel<T>(dst: &mut T, old: T, src: T) -> T;
pub fn atomic_cxchg<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_acq<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_cxchg_rel<T>(dst: &T, old: T, src: T) -> T;
pub fn atomic_load<T>(src: &T) -> T;
pub fn atomic_load_acq<T>(src: &T) -> T;
pub fn atomic_store<T>(dst: &mut T, val: T);
pub fn atomic_store_rel<T>(dst: &mut T, val: T);
pub fn atomic_store<T>(dst: &T, val: T);
pub fn atomic_store_rel<T>(dst: &T, val: T);
pub fn atomic_xchg<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xchg_acq<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xchg_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xchg<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xchg_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xadd_acq<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xadd_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xadd<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xadd_rel<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xsub_acq<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xsub_rel<T>(dst: &mut T, src: T) -> T;
pub fn atomic_xsub<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_acq<T>(dst: &T, src: T) -> T;
pub fn atomic_xsub_rel<T>(dst: &T, src: T) -> T;
}
}