Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 1597 insertions, 0 deletions

diff --git a/third_party/rust/atomic/src/fallback.rs b/third_party/rust/atomic/src/fallback.rs
new file mode 100644
index 0000000000..8b7e86119b
--- /dev/null
+++ b/third_party/rust/atomic/src/fallback.rs
@@ -0,0 +1,196 @@
+// Copyright 2016 Amanieu d'Antras
+//
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://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.
+
+use core::cmp;
+use core::mem;
+use core::num::Wrapping;
+use core::ops;
+use core::ptr;
+use core::slice;
+use core::sync::atomic::{self, AtomicUsize, Ordering};
+
+// We use an AtomicUsize instead of an AtomicBool because it performs better
+// on architectures that don't have byte-sized atomics.
+//
+// We give each spinlock its own cache line to avoid false sharing.
+#[repr(align(64))]
+struct SpinLock(AtomicUsize);
+
+impl SpinLock {
+    fn lock(&self) {
+        while self
+            .0
+            .compare_exchange_weak(0, 1, Ordering::Acquire, Ordering::Relaxed)
+            .is_err()
+        {
+            while self.0.load(Ordering::Relaxed) != 0 {
+                atomic::spin_loop_hint();
+            }
+        }
+    }
+
+    fn unlock(&self) {
+        self.0.store(0, Ordering::Release);
+    }
+}
+
+// A big array of spinlocks which we use to guard atomic accesses. A spinlock is
+// chosen based on a hash of the address of the atomic object, which helps to
+// reduce contention compared to a single global lock.
+macro_rules! array {
+    (@accum (0, $($_es:expr),*) -> ($($body:tt)*))
+        => {array!(@as_expr [$($body)*])};
+    (@accum (1, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (0, $($es),*) -> ($($body)* $($es,)*))};
+    (@accum (2, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (0, $($es),*) -> ($($body)* $($es,)* $($es,)*))};
+    (@accum (4, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (2, $($es,)* $($es),*) -> ($($body)*))};
+    (@accum (8, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (4, $($es,)* $($es),*) -> ($($body)*))};
+    (@accum (16, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (8, $($es,)* $($es),*) -> ($($body)*))};
+    (@accum (32, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (16, $($es,)* $($es),*) -> ($($body)*))};
+    (@accum (64, $($es:expr),*) -> ($($body:tt)*))
+        => {array!(@accum (32, $($es,)* $($es),*) -> ($($body)*))};
+
+    (@as_expr $e:expr) => {$e};
+
+    [$e:expr; $n:tt] => { array!(@accum ($n, $e) -> ()) };
+}
+static SPINLOCKS: [SpinLock; 64] = array![SpinLock(AtomicUsize::new(0)); 64];
+
+// Spinlock pointer hashing function from compiler-rt
+#[inline]
+fn lock_for_addr(addr: usize) -> &'static SpinLock {
+    // Disregard the lowest 4 bits.  We want all values that may be part of the
+    // same memory operation to hash to the same value and therefore use the same
+    // lock.
+    let mut hash = addr >> 4;
+    // Use the next bits as the basis for the hash
+    let low = hash & (SPINLOCKS.len() - 1);
+    // Now use the high(er) set of bits to perturb the hash, so that we don't
+    // get collisions from atomic fields in a single object
+    hash >>= 16;
+    hash ^= low;
+    // Return a pointer to the lock to use
+    &SPINLOCKS[hash & (SPINLOCKS.len() - 1)]
+}
+
+#[inline]
+fn lock(addr: usize) -> LockGuard {
+    let lock = lock_for_addr(addr);
+    lock.lock();
+    LockGuard(lock)
+}
+
+struct LockGuard(&'static SpinLock);
+impl Drop for LockGuard {
+    #[inline]
+    fn drop(&mut self) {
+        self.0.unlock();
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_load<T>(dst: *mut T) -> T {
+    let _l = lock(dst as usize);
+    ptr::read(dst)
+}
+
+#[inline]
+pub unsafe fn atomic_store<T>(dst: *mut T, val: T) {
+    let _l = lock(dst as usize);
+    ptr::write(dst, val);
+}
+
+#[inline]
+pub unsafe fn atomic_swap<T>(dst: *mut T, val: T) -> T {
+    let _l = lock(dst as usize);
+    ptr::replace(dst, val)
+}
+
+#[inline]
+pub unsafe fn atomic_compare_exchange<T>(dst: *mut T, current: T, new: T) -> Result<T, T> {
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    // compare_exchange compares with memcmp instead of Eq
+    let a = slice::from_raw_parts(&result as *const _ as *const u8, mem::size_of_val(&result));
+    let b = slice::from_raw_parts(
+        &current as *const _ as *const u8,
+        mem::size_of_val(&current),
+    );
+    if a == b {
+        ptr::write(dst, new);
+        Ok(result)
+    } else {
+        Err(result)
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_add<T: Copy>(dst: *mut T, val: T) -> T
+where
+    Wrapping<T>: ops::Add<Output = Wrapping<T>>,
+{
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, (Wrapping(result) + Wrapping(val)).0);
+    result
+}
+
+#[inline]
+pub unsafe fn atomic_sub<T: Copy>(dst: *mut T, val: T) -> T
+where
+    Wrapping<T>: ops::Sub<Output = Wrapping<T>>,
+{
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, (Wrapping(result) - Wrapping(val)).0);
+    result
+}
+
+#[inline]
+pub unsafe fn atomic_and<T: Copy + ops::BitAnd<Output = T>>(dst: *mut T, val: T) -> T {
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, result & val);
+    result
+}
+
+#[inline]
+pub unsafe fn atomic_or<T: Copy + ops::BitOr<Output = T>>(dst: *mut T, val: T) -> T {
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, result | val);
+    result
+}
+
+#[inline]
+pub unsafe fn atomic_xor<T: Copy + ops::BitXor<Output = T>>(dst: *mut T, val: T) -> T {
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, result ^ val);
+    result
+}
+
+#[inline]
+pub unsafe fn atomic_min<T: Copy + cmp::Ord>(dst: *mut T, val: T) -> T {
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, cmp::min(result, val));
+    result
+}
+
+#[inline]
+pub unsafe fn atomic_max<T: Copy + cmp::Ord>(dst: *mut T, val: T) -> T {
+    let _l = lock(dst as usize);
+    let result = ptr::read(dst);
+    ptr::write(dst, cmp::max(result, val));
+    result
+}
diff --git a/third_party/rust/atomic/src/lib.rs b/third_party/rust/atomic/src/lib.rs
new file mode 100644
index 0000000000..d6b19a651b
--- /dev/null
+++ b/third_party/rust/atomic/src/lib.rs
@@ -0,0 +1,735 @@
+// Copyright 2016 Amanieu d'Antras
+//
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://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.
+
+//! Generic `Atomic<T>` wrapper type
+//!
+//! Atomic types provide primitive shared-memory communication between
+//! threads, and are the building blocks of other concurrent types.
+//!
+//! This library defines a generic atomic wrapper type `Atomic<T>` for all
+//! `T: Copy` types.
+//! 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 [LLVM atomic orderings][1].
+//!
+//! [1]: http://llvm.org/docs/LangRef.html#memory-model-for-concurrent-operations
+//!
+//! Atomic variables are safe to share between threads (they implement `Sync`)
+//! 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 `const fn` constructors (only available on nightly). Atomic statics
+//! are often used for lazy global initialization.
+
+#![warn(missing_docs)]
+#![no_std]
+#![cfg_attr(
+    feature = "nightly", feature(const_fn, cfg_target_has_atomic, atomic_min_max)
+)]
+
+#[cfg(any(test, feature = "std"))]
+#[macro_use]
+extern crate std;
+
+// Re-export some useful definitions from libcore
+pub use core::sync::atomic::{fence, Ordering};
+
+use core::cell::UnsafeCell;
+use core::fmt;
+
+#[cfg(feature = "std")]
+use std::panic::RefUnwindSafe;
+
+mod fallback;
+mod ops;
+
+/// A generic atomic wrapper type which allows an object to be safely shared
+/// between threads.
+pub struct Atomic<T: Copy> {
+    v: UnsafeCell<T>,
+}
+
+// Atomic<T> is only Sync if T is Send
+unsafe impl<T: Copy + Send> Sync for Atomic<T> {}
+
+// Given that atomicity is guaranteed, Atomic<T> is RefUnwindSafe if T is
+//
+// This is trivially correct for native lock-free atomic types. For those whose
+// atomicity is emulated using a spinlock, it is still correct because the
+// `Atomic` API does not allow doing any panic-inducing operation after writing
+// to the target object.
+#[cfg(feature = "std")]
+impl<T: Copy + RefUnwindSafe> RefUnwindSafe for Atomic<T> {}
+
+impl<T: Copy + Default> Default for Atomic<T> {
+    #[inline]
+    fn default() -> Self {
+        Self::new(Default::default())
+    }
+}
+
+impl<T: Copy + fmt::Debug> fmt::Debug for Atomic<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple("Atomic")
+            .field(&self.load(Ordering::SeqCst))
+            .finish()
+    }
+}
+
+impl<T: Copy> Atomic<T> {
+    /// Creates a new `Atomic`.
+    #[inline]
+    #[cfg(feature = "nightly")]
+    pub const fn new(v: T) -> Atomic<T> {
+        Atomic {
+            v: UnsafeCell::new(v),
+        }
+    }
+
+    /// Creates a new `Atomic`.
+    #[inline]
+    #[cfg(not(feature = "nightly"))]
+    pub fn new(v: T) -> Atomic<T> {
+        Atomic {
+            v: UnsafeCell::new(v),
+        }
+    }
+
+    /// Checks if `Atomic` objects of this type are lock-free.
+    ///
+    /// If an `Atomic` is not lock-free then it may be implemented using locks
+    /// internally, which makes it unsuitable for some situations (such as
+    /// communicating with a signal handler).
+    #[inline]
+    #[cfg(feature = "nightly")]
+    pub const fn is_lock_free() -> bool {
+        ops::atomic_is_lock_free::<T>()
+    }
+
+    /// Checks if `Atomic` objects of this type are lock-free.
+    ///
+    /// If an `Atomic` is not lock-free then it may be implemented using locks
+    /// internally, which makes it unsuitable for some situations (such as
+    /// communicating with a signal handler).
+    #[inline]
+    #[cfg(not(feature = "nightly"))]
+    pub fn is_lock_free() -> bool {
+        ops::atomic_is_lock_free::<T>()
+    }
+
+    /// Returns a mutable reference to the underlying type.
+    ///
+    /// This is safe because the mutable reference guarantees that no other threads are
+    /// concurrently accessing the atomic data.
+    #[inline]
+    pub fn get_mut(&mut self) -> &mut T {
+        unsafe { &mut *self.v.get() }
+    }
+
+    /// Consumes the atomic and returns the contained value.
+    ///
+    /// This is safe because passing `self` by value guarantees that no other threads are
+    /// concurrently accessing the atomic data.
+    #[inline]
+    pub fn into_inner(self) -> T {
+        self.v.into_inner()
+    }
+
+    /// Loads a value from the `Atomic`.
+    ///
+    /// `load` takes an `Ordering` argument which describes the memory ordering
+    /// of this operation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `order` is `Release` or `AcqRel`.
+    #[inline]
+    pub fn load(&self, order: Ordering) -> T {
+        unsafe { ops::atomic_load(self.v.get(), order) }
+    }
+
+    /// Stores a value into the `Atomic`.
+    ///
+    /// `store` takes an `Ordering` argument which describes the memory ordering
+    /// of this operation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `order` is `Acquire` or `AcqRel`.
+    #[inline]
+    pub fn store(&self, val: T, order: Ordering) {
+        unsafe {
+            ops::atomic_store(self.v.get(), val, order);
+        }
+    }
+
+    /// Stores a value into the `Atomic`, returning the old value.
+    ///
+    /// `swap` takes an `Ordering` argument which describes the memory ordering
+    /// of this operation.
+    #[inline]
+    pub fn swap(&self, val: T, order: Ordering) -> T {
+        unsafe { ops::atomic_swap(self.v.get(), val, order) }
+    }
+
+    /// Stores a value into the `Atomic` if the current value is the same as the
+    /// `current` value.
+    ///
+    /// The return value is a result indicating whether the new value was
+    /// written and containing the previous value. On success this value is
+    /// guaranteed to be equal to `new`.
+    ///
+    /// `compare_exchange` takes two `Ordering` arguments to describe the memory
+    /// ordering of this operation. The first describes the required ordering if
+    /// the operation succeeds while the second describes the required ordering
+    /// when the operation fails. The failure ordering can't be `Acquire` or
+    /// `AcqRel` and must be equivalent or weaker than the success ordering.
+    #[inline]
+    pub fn compare_exchange(
+        &self,
+        current: T,
+        new: T,
+        success: Ordering,
+        failure: Ordering,
+    ) -> Result<T, T> {
+        unsafe { ops::atomic_compare_exchange(self.v.get(), current, new, success, failure) }
+    }
+
+    /// Stores a value into the `Atomic` if the current value is the same as the
+    /// `current` value.
+    ///
+    /// Unlike `compare_exchange`, this function is allowed to spuriously fail
+    /// even when the comparison succeeds, which can result in more efficient
+    /// code on some platforms. The return value is a result indicating whether
+    /// the new value was written and containing the previous value.
+    ///
+    /// `compare_exchange` takes two `Ordering` arguments to describe the memory
+    /// ordering of this operation. The first describes the required ordering if
+    /// the operation succeeds while the second describes the required ordering
+    /// when the operation fails. The failure ordering can't be `Acquire` or
+    /// `AcqRel` and must be equivalent or weaker than the success ordering.
+    /// success ordering.
+    #[inline]
+    pub fn compare_exchange_weak(
+        &self,
+        current: T,
+        new: T,
+        success: Ordering,
+        failure: Ordering,
+    ) -> Result<T, T> {
+        unsafe { ops::atomic_compare_exchange_weak(self.v.get(), current, new, success, failure) }
+    }
+}
+
+impl Atomic<bool> {
+    /// Logical "and" with a boolean value.
+    ///
+    /// 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.
+    #[inline]
+    pub fn fetch_and(&self, val: bool, order: Ordering) -> bool {
+        unsafe { ops::atomic_and(self.v.get(), val, order) }
+    }
+
+    /// Logical "or" with a boolean value.
+    ///
+    /// 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.
+    #[inline]
+    pub fn fetch_or(&self, val: bool, order: Ordering) -> bool {
+        unsafe { ops::atomic_or(self.v.get(), val, order) }
+    }
+
+    /// Logical "xor" with a boolean value.
+    ///
+    /// 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.
+    #[inline]
+    pub fn fetch_xor(&self, val: bool, order: Ordering) -> bool {
+        unsafe { ops::atomic_xor(self.v.get(), val, order) }
+    }
+}
+
+macro_rules! atomic_ops_common {
+    ($($t:ty)*) => ($(
+        impl Atomic<$t> {
+            /// Add to the current value, returning the previous value.
+            #[inline]
+            pub fn fetch_add(&self, val: $t, order: Ordering) -> $t {
+                unsafe { ops::atomic_add(self.v.get(), val, order) }
+            }
+
+            /// Subtract from the current value, returning the previous value.
+            #[inline]
+            pub fn fetch_sub(&self, val: $t, order: Ordering) -> $t {
+                unsafe { ops::atomic_sub(self.v.get(), val, order) }
+            }
+
+            /// Bitwise and with the current value, returning the previous value.
+            #[inline]
+            pub fn fetch_and(&self, val: $t, order: Ordering) -> $t {
+                unsafe { ops::atomic_and(self.v.get(), val, order) }
+            }
+
+            /// Bitwise or with the current value, returning the previous value.
+            #[inline]
+            pub fn fetch_or(&self, val: $t, order: Ordering) -> $t {
+                unsafe { ops::atomic_or(self.v.get(), val, order) }
+            }
+
+            /// Bitwise xor with the current value, returning the previous value.
+            #[inline]
+            pub fn fetch_xor(&self, val: $t, order: Ordering) -> $t {
+                unsafe { ops::atomic_xor(self.v.get(), val, order) }
+            }
+        }
+    )*);
+}
+macro_rules! atomic_ops_signed {
+    ($($t:ty)*) => (
+        atomic_ops_common!{ $($t)* }
+        $(
+            impl Atomic<$t> {
+                /// Minimum with the current value.
+                #[inline]
+                pub fn fetch_min(&self, val: $t, order: Ordering) -> $t {
+                    unsafe { ops::atomic_min(self.v.get(), val, order) }
+                }
+
+                /// Maximum with the current value.
+                #[inline]
+                pub fn fetch_max(&self, val: $t, order: Ordering) -> $t {
+                    unsafe { ops::atomic_max(self.v.get(), val, order) }
+                }
+            }
+        )*
+    );
+}
+macro_rules! atomic_ops_unsigned {
+    ($($t:ty)*) => (
+        atomic_ops_common!{ $($t)* }
+        $(
+            impl Atomic<$t> {
+                /// Minimum with the current value.
+                #[inline]
+                pub fn fetch_min(&self, val: $t, order: Ordering) -> $t {
+                    unsafe { ops::atomic_umin(self.v.get(), val, order) }
+                }
+
+                /// Maximum with the current value.
+                #[inline]
+                pub fn fetch_max(&self, val: $t, order: Ordering) -> $t {
+                    unsafe { ops::atomic_umax(self.v.get(), val, order) }
+                }
+            }
+        )*
+    );
+}
+atomic_ops_signed!{ i8 i16 i32 i64 isize i128 }
+atomic_ops_unsigned!{ u8 u16 u32 u64 usize u128 }
+
+#[cfg(test)]
+mod tests {
+    use core::mem;
+    use Atomic;
+    use Ordering::*;
+
+    #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)]
+    struct Foo(u8, u8);
+    #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)]
+    struct Bar(u64, u64);
+    #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)]
+    struct Quux(u32);
+
+    #[test]
+    fn atomic_bool() {
+        let a = Atomic::new(false);
+        assert_eq!(Atomic::<bool>::is_lock_free(), cfg!(feature = "nightly"));
+        assert_eq!(format!("{:?}", a), "Atomic(false)");
+        assert_eq!(a.load(SeqCst), false);
+        a.store(true, SeqCst);
+        assert_eq!(a.swap(false, SeqCst), true);
+        assert_eq!(a.compare_exchange(true, false, SeqCst, SeqCst), Err(false));
+        assert_eq!(a.compare_exchange(false, true, SeqCst, SeqCst), Ok(false));
+        assert_eq!(a.fetch_and(false, SeqCst), true);
+        assert_eq!(a.fetch_or(true, SeqCst), false);
+        assert_eq!(a.fetch_xor(false, SeqCst), true);
+        assert_eq!(a.load(SeqCst), true);
+    }
+
+    #[test]
+    fn atomic_i8() {
+        let a = Atomic::new(0i8);
+        assert_eq!(
+            Atomic::<i8>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "8",
+                all(feature = "nightly", target_has_atomic = "8")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        // Make sure overflows are handled correctly
+        assert_eq!(a.fetch_sub(-56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), -74);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(-25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_i16() {
+        let a = Atomic::new(0i16);
+        assert_eq!(
+            Atomic::<i16>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "16",
+                all(feature = "nightly", target_has_atomic = "16")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(-56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 182);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(-25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_i32() {
+        let a = Atomic::new(0i32);
+        assert_eq!(
+            Atomic::<i32>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "32",
+                all(feature = "nightly", target_has_atomic = "32")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(-56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 182);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(-25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_i64() {
+        let a = Atomic::new(0i64);
+        assert_eq!(
+            Atomic::<i64>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "64",
+                all(feature = "nightly", target_has_atomic = "64")
+            )) && mem::align_of::<i64>() == 8
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(-56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 182);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(-25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_i128() {
+        let a = Atomic::new(0i128);
+        assert_eq!(
+            Atomic::<i128>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "128",
+                all(feature = "nightly", target_has_atomic = "128")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(-56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 182);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(-25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_isize() {
+        let a = Atomic::new(0isize);
+        assert!(Atomic::<isize>::is_lock_free());
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(-56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 182);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(-25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_u8() {
+        let a = Atomic::new(0u8);
+        assert_eq!(
+            Atomic::<u8>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "8",
+                all(feature = "nightly", target_has_atomic = "8")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 70);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_u16() {
+        let a = Atomic::new(0u16);
+        assert_eq!(
+            Atomic::<u16>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "16",
+                all(feature = "nightly", target_has_atomic = "16")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 70);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_u32() {
+        let a = Atomic::new(0u32);
+        assert_eq!(
+            Atomic::<u32>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "32",
+                all(feature = "nightly", target_has_atomic = "32")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 70);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_u64() {
+        let a = Atomic::new(0u64);
+        assert_eq!(
+            Atomic::<u64>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "64",
+                all(feature = "nightly", target_has_atomic = "64")
+            )) && mem::align_of::<u64>() == 8
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 70);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_u128() {
+        let a = Atomic::new(0u128);
+        assert_eq!(
+            Atomic::<u128>::is_lock_free(),
+            cfg!(any(
+                target_pointer_width = "128",
+                all(feature = "nightly", target_has_atomic = "128")
+            ))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 70);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_usize() {
+        let a = Atomic::new(0usize);
+        assert!(Atomic::<usize>::is_lock_free());
+        assert_eq!(format!("{:?}", a), "Atomic(0)");
+        assert_eq!(a.load(SeqCst), 0);
+        a.store(1, SeqCst);
+        assert_eq!(a.swap(2, SeqCst), 1);
+        assert_eq!(a.compare_exchange(5, 45, SeqCst, SeqCst), Err(2));
+        assert_eq!(a.compare_exchange(2, 3, SeqCst, SeqCst), Ok(2));
+        assert_eq!(a.fetch_add(123, SeqCst), 3);
+        assert_eq!(a.fetch_sub(56, SeqCst), 126);
+        assert_eq!(a.fetch_and(7, SeqCst), 70);
+        assert_eq!(a.fetch_or(64, SeqCst), 6);
+        assert_eq!(a.fetch_xor(1, SeqCst), 70);
+        assert_eq!(a.fetch_min(30, SeqCst), 71);
+        assert_eq!(a.fetch_max(25, SeqCst), 30);
+        assert_eq!(a.load(SeqCst), 30);
+    }
+
+    #[test]
+    fn atomic_foo() {
+        let a = Atomic::default();
+        assert_eq!(Atomic::<Foo>::is_lock_free(), false);
+        assert_eq!(format!("{:?}", a), "Atomic(Foo(0, 0))");
+        assert_eq!(a.load(SeqCst), Foo(0, 0));
+        a.store(Foo(1, 1), SeqCst);
+        assert_eq!(a.swap(Foo(2, 2), SeqCst), Foo(1, 1));
+        assert_eq!(
+            a.compare_exchange(Foo(5, 5), Foo(45, 45), SeqCst, SeqCst),
+            Err(Foo(2, 2))
+        );
+        assert_eq!(
+            a.compare_exchange(Foo(2, 2), Foo(3, 3), SeqCst, SeqCst),
+            Ok(Foo(2, 2))
+        );
+        assert_eq!(a.load(SeqCst), Foo(3, 3));
+    }
+
+    #[test]
+    fn atomic_bar() {
+        let a = Atomic::default();
+        assert_eq!(Atomic::<Bar>::is_lock_free(), false);
+        assert_eq!(format!("{:?}", a), "Atomic(Bar(0, 0))");
+        assert_eq!(a.load(SeqCst), Bar(0, 0));
+        a.store(Bar(1, 1), SeqCst);
+        assert_eq!(a.swap(Bar(2, 2), SeqCst), Bar(1, 1));
+        assert_eq!(
+            a.compare_exchange(Bar(5, 5), Bar(45, 45), SeqCst, SeqCst),
+            Err(Bar(2, 2))
+        );
+        assert_eq!(
+            a.compare_exchange(Bar(2, 2), Bar(3, 3), SeqCst, SeqCst),
+            Ok(Bar(2, 2))
+        );
+        assert_eq!(a.load(SeqCst), Bar(3, 3));
+    }
+
+    #[test]
+    fn atomic_quxx() {
+        let a = Atomic::default();
+        assert_eq!(
+            Atomic::<Quux>::is_lock_free(),
+            cfg!(any(feature = "nightly", target_pointer_width = "32"))
+        );
+        assert_eq!(format!("{:?}", a), "Atomic(Quux(0))");
+        assert_eq!(a.load(SeqCst), Quux(0));
+        a.store(Quux(1), SeqCst);
+        assert_eq!(a.swap(Quux(2), SeqCst), Quux(1));
+        assert_eq!(
+            a.compare_exchange(Quux(5), Quux(45), SeqCst, SeqCst),
+            Err(Quux(2))
+        );
+        assert_eq!(
+            a.compare_exchange(Quux(2), Quux(3), SeqCst, SeqCst),
+            Ok(Quux(2))
+        );
+        assert_eq!(a.load(SeqCst), Quux(3));
+    }
+}
diff --git a/third_party/rust/atomic/src/ops.rs b/third_party/rust/atomic/src/ops.rs
new file mode 100644
index 0000000000..3626c9ed9a
--- /dev/null
+++ b/third_party/rust/atomic/src/ops.rs
@@ -0,0 +1,666 @@
+// Copyright 2016 Amanieu d'Antras
+//
+// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
+// http://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.
+
+use core::cmp;
+use core::mem;
+use core::num::Wrapping;
+use core::ops;
+use core::sync::atomic::Ordering;
+use fallback;
+
+#[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+use core::sync::atomic::{ AtomicI8, AtomicU8 };
+#[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+use core::sync::atomic::{ AtomicI16, AtomicU16 };
+#[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+use core::sync::atomic::{ AtomicI32, AtomicU32 };
+#[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+use core::sync::atomic::{ AtomicI64, AtomicU64 };
+
+#[cfg(not(feature = "nightly"))]
+use core::sync::atomic::AtomicUsize;
+#[cfg(not(feature = "nightly"))]
+const SIZEOF_USIZE: usize = mem::size_of::<usize>();
+#[cfg(not(feature = "nightly"))]
+const ALIGNOF_USIZE: usize = mem::align_of::<usize>();
+
+#[cfg(feature = "nightly")]
+#[inline]
+pub const fn atomic_is_lock_free<T>() -> bool {
+    let size = mem::size_of::<T>();
+    // FIXME: switch to … && … && … once that operator is supported in const functions
+    (1 == size.count_ones()) & (8 >= size) & (mem::align_of::<T>() >= size)
+}
+
+#[cfg(not(feature = "nightly"))]
+#[inline]
+pub fn atomic_is_lock_free<T>() -> bool {
+    let size = mem::size_of::<T>();
+    1 == size.count_ones() && SIZEOF_USIZE >= size && mem::align_of::<T>() >= ALIGNOF_USIZE
+}
+
+#[inline]
+pub unsafe fn atomic_load<T>(dst: *mut T, order: Ordering) -> T {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(&(*(dst as *const AtomicU8)).load(order))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(&(*(dst as *const AtomicU16)).load(order))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(&(*(dst as *const AtomicU32)).load(order))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(&(*(dst as *const AtomicU64)).load(order))
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(&(*(dst as *const AtomicUsize)).load(order))
+        }
+        _ => fallback::atomic_load(dst),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_store<T>(dst: *mut T, val: T, order: Ordering) {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            (*(dst as *const AtomicU8)).store(mem::transmute_copy(&val), order)
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            (*(dst as *const AtomicU16)).store(mem::transmute_copy(&val), order)
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            (*(dst as *const AtomicU32)).store(mem::transmute_copy(&val), order)
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            (*(dst as *const AtomicU64)).store(mem::transmute_copy(&val), order)
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            (*(dst as *const AtomicUsize)).store(mem::transmute_copy(&val), order)
+        }
+        _ => fallback::atomic_store(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_swap<T>(dst: *mut T, val: T, order: Ordering) -> T {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(&(*(dst as *const AtomicU8)).swap(mem::transmute_copy(&val), order))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).swap(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).swap(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).swap(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicUsize)).swap(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_swap(dst, val),
+    }
+}
+
+#[inline]
+unsafe fn map_result<T, U>(r: Result<T, T>) -> Result<U, U> {
+    match r {
+        Ok(x) => Ok(mem::transmute_copy(&x)),
+        Err(x) => Err(mem::transmute_copy(&x)),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_compare_exchange<T>(
+    dst: *mut T,
+    current: T,
+    new: T,
+    success: Ordering,
+    failure: Ordering,
+) -> Result<T, T> {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            map_result((*(dst as *const AtomicU8)).compare_exchange(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            map_result((*(dst as *const AtomicU16)).compare_exchange(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            map_result((*(dst as *const AtomicU32)).compare_exchange(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            map_result((*(dst as *const AtomicU64)).compare_exchange(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            map_result((*(dst as *const AtomicUsize)).compare_exchange(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        _ => fallback::atomic_compare_exchange(dst, current, new),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_compare_exchange_weak<T>(
+    dst: *mut T,
+    current: T,
+    new: T,
+    success: Ordering,
+    failure: Ordering,
+) -> Result<T, T> {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            map_result((*(dst as *const AtomicU8)).compare_exchange_weak(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            map_result((*(dst as *const AtomicU16)).compare_exchange_weak(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            map_result((*(dst as *const AtomicU32)).compare_exchange_weak(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            map_result((*(dst as *const AtomicU64)).compare_exchange_weak(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            map_result((*(dst as *const AtomicUsize)).compare_exchange_weak(
+                mem::transmute_copy(&current),
+                mem::transmute_copy(&new),
+                success,
+                failure,
+            ))
+        }
+        _ => fallback::atomic_compare_exchange(dst, current, new),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_add<T: Copy>(dst: *mut T, val: T, order: Ordering) -> T
+where
+    Wrapping<T>: ops::Add<Output = Wrapping<T>>,
+{
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_add(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_add(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_add(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_add(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicUsize)).fetch_add(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_add(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_sub<T: Copy>(dst: *mut T, val: T, order: Ordering) -> T
+where
+    Wrapping<T>: ops::Sub<Output = Wrapping<T>>,
+{
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_sub(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_sub(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_sub(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_sub(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicUsize)).fetch_sub(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_sub(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_and<T: Copy + ops::BitAnd<Output = T>>(
+    dst: *mut T,
+    val: T,
+    order: Ordering,
+) -> T {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_and(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_and(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_and(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_and(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicUsize)).fetch_and(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_and(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_or<T: Copy + ops::BitOr<Output = T>>(
+    dst: *mut T,
+    val: T,
+    order: Ordering,
+) -> T {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_or(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_or(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_or(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_or(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicUsize)).fetch_or(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_or(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_xor<T: Copy + ops::BitXor<Output = T>>(
+    dst: *mut T,
+    val: T,
+    order: Ordering,
+) -> T {
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_xor(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_xor(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_xor(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_xor(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(not(feature = "nightly"))]
+        SIZEOF_USIZE if mem::align_of::<T>() >= ALIGNOF_USIZE =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicUsize)).fetch_xor(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_xor(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_min<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T {
+    // Silence warning, fetch_min is not stable yet
+    #[cfg(not(feature = "nightly"))]
+    let _ = order;
+
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI8)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI16)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI32)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI64)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_min(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_max<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T {
+    // Silence warning, fetch_min is not stable yet
+    #[cfg(not(feature = "nightly"))]
+    let _ = order;
+
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI8)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI16)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI32)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicI64)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_max(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_umin<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T {
+    // Silence warning, fetch_min is not stable yet
+    #[cfg(not(feature = "nightly"))]
+    let _ = order;
+
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_min(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_min(dst, val),
+    }
+}
+
+#[inline]
+pub unsafe fn atomic_umax<T: Copy + cmp::Ord>(dst: *mut T, val: T, order: Ordering) -> T {
+    // Silence warning, fetch_min is not stable yet
+    #[cfg(not(feature = "nightly"))]
+    let _ = order;
+
+    match mem::size_of::<T>() {
+        #[cfg(all(feature = "nightly", target_has_atomic = "8"))]
+        1 if mem::align_of::<T>() >= 1 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU8)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "16"))]
+        2 if mem::align_of::<T>() >= 2 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU16)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "32"))]
+        4 if mem::align_of::<T>() >= 4 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU32)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        #[cfg(all(feature = "nightly", target_has_atomic = "64"))]
+        8 if mem::align_of::<T>() >= 8 =>
+        {
+            mem::transmute_copy(
+                &(*(dst as *const AtomicU64)).fetch_max(mem::transmute_copy(&val), order),
+            )
+        }
+        _ => fallback::atomic_max(dst, val),
+    }
+}