use generic Atomic type where possible

in core/alloc/std only for now, and ignoring test files

Co-authored-by: Pavel Grigorenko <[email protected]>

Author: CAD97

library/alloc/src/lib.rs

@@ -120,6 +120,7 @@
 #![feature(fmt_internals)]
 #![feature(fn_traits)]
 #![feature(formatting_options)]
+#![feature(generic_atomic)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(inplace_iteration)]
 #![feature(iter_advance_by)]

library/alloc/src/sync.rs

@@ -25,8 +25,8 @@ use core::pin::{Pin, PinCoerceUnsized};
 use core::ptr::{self, NonNull};
 #[cfg(not(no_global_oom_handling))]
 use core::slice::from_raw_parts_mut;
-use core::sync::atomic;
 use core::sync::atomic::Ordering::{Acquire, Relaxed, Release};
+use core::sync::atomic::{self, Atomic};
 use core::{borrow, fmt, hint};
 
 #[cfg(not(no_global_oom_handling))]
@@ -348,12 +348,12 @@ impl<T: ?Sized, A: Allocator> fmt::Debug for Weak<T, A> {
 // inner types.
 #[repr(C)]
 struct ArcInner<T: ?Sized> {
-    strong: atomic::AtomicUsize,
+    strong: Atomic<usize>,
 
     // the value usize::MAX acts as a sentinel for temporarily "locking" the
     // ability to upgrade weak pointers or downgrade strong ones; this is used
     // to avoid races in `make_mut` and `get_mut`.
-    weak: atomic::AtomicUsize,
+    weak: Atomic<usize>,
 
     data: T,
 }
@@ -2724,8 +2724,8 @@ impl<T, A: Allocator> Weak<T, A> {
 /// Helper type to allow accessing the reference counts without
 /// making any assertions about the data field.
 struct WeakInner<'a> {
-    weak: &'a atomic::AtomicUsize,
-    strong: &'a atomic::AtomicUsize,
+    weak: &'a Atomic<usize>,
+    strong: &'a Atomic<usize>,
 }
 
 impl<T: ?Sized> Weak<T> {

library/std/src/alloc.rs

@@ -57,7 +57,7 @@
 #![stable(feature = "alloc_module", since = "1.28.0")]
 
 use core::ptr::NonNull;
-use core::sync::atomic::{AtomicPtr, Ordering};
+use core::sync::atomic::{Atomic, AtomicPtr, Ordering};
 use core::{hint, mem, ptr};
 
 #[stable(feature = "alloc_module", since = "1.28.0")]
@@ -287,7 +287,7 @@ unsafe impl Allocator for System {
     }
 }
 
-static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
+static HOOK: Atomic<*mut ()> = AtomicPtr::new(ptr::null_mut());
 
 /// Registers a custom allocation error hook, replacing any that was previously registered.
 ///

library/std/src/backtrace.rs

@@ -92,8 +92,8 @@ use crate::backtrace_rs::{self, BytesOrWideString};
 use crate::ffi::c_void;
 use crate::panic::UnwindSafe;
 use crate::sync::LazyLock;
-use crate::sync::atomic::AtomicU8;
 use crate::sync::atomic::Ordering::Relaxed;
+use crate::sync::atomic::{Atomic, AtomicU8};
 use crate::sys::backtrace::{lock, output_filename, set_image_base};
 use crate::{env, fmt};
 
@@ -254,7 +254,7 @@ impl Backtrace {
         // Cache the result of reading the environment variables to make
         // backtrace captures speedy, because otherwise reading environment
         // variables every time can be somewhat slow.
-        static ENABLED: AtomicU8 = AtomicU8::new(0);
+        static ENABLED: Atomic<u8> = AtomicU8::new(0);
         match ENABLED.load(Relaxed) {
             0 => {}
             1 => return false,

library/std/src/io/stdio.rs

@@ -11,7 +11,7 @@ use crate::io::{
     self, BorrowedCursor, BufReader, IoSlice, IoSliceMut, LineWriter, Lines, SpecReadByte,
 };
 use crate::panic::{RefUnwindSafe, UnwindSafe};
-use crate::sync::atomic::{AtomicBool, Ordering};
+use crate::sync::atomic::{Atomic, AtomicBool, Ordering};
 use crate::sync::{Arc, Mutex, MutexGuard, OnceLock, ReentrantLock, ReentrantLockGuard};
 use crate::sys::stdio;
 use crate::thread::AccessError;
@@ -37,7 +37,7 @@ thread_local! {
 /// have a consistent order between set_output_capture and print_to *within
 /// the same thread*. Within the same thread, things always have a perfectly
 /// consistent order. So Ordering::Relaxed is fine.
-static OUTPUT_CAPTURE_USED: AtomicBool = AtomicBool::new(false);
+static OUTPUT_CAPTURE_USED: Atomic<bool> = AtomicBool::new(false);
 
 /// A handle to a raw instance of the standard input stream of this process.
 ///

library/std/src/lib.rs

@@ -336,6 +336,7 @@
 #![feature(float_gamma)]
 #![feature(float_minimum_maximum)]
 #![feature(fmt_internals)]
+#![feature(generic_atomic)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(hashmap_internals)]
 #![feature(hint_must_use)]

library/std/src/os/uefi/env.rs

@@ -4,13 +4,13 @@
 
 use crate::ffi::c_void;
 use crate::ptr::NonNull;
-use crate::sync::atomic::{AtomicBool, AtomicPtr, Ordering};
+use crate::sync::atomic::{Atomic, AtomicBool, AtomicPtr, Ordering};
 
-static SYSTEM_TABLE: AtomicPtr<c_void> = AtomicPtr::new(crate::ptr::null_mut());
-static IMAGE_HANDLE: AtomicPtr<c_void> = AtomicPtr::new(crate::ptr::null_mut());
+static SYSTEM_TABLE: Atomic<*mut c_void> = AtomicPtr::new(crate::ptr::null_mut());
+static IMAGE_HANDLE: Atomic<*mut c_void> = AtomicPtr::new(crate::ptr::null_mut());
 // Flag to check if BootServices are still valid.
 // Start with assuming that they are not available
-static BOOT_SERVICES_FLAG: AtomicBool = AtomicBool::new(false);
+static BOOT_SERVICES_FLAG: Atomic<bool> = AtomicBool::new(false);
 
 /// Initializes the global System Table and Image Handle pointers.
 ///

library/std/src/os/xous/services.rs

@@ -1,4 +1,4 @@
-use core::sync::atomic::{AtomicU32, Ordering};
+use core::sync::atomic::{Atomic, AtomicU32, Ordering};
 
 use crate::os::xous::ffi::Connection;
 
@@ -106,7 +106,7 @@ pub fn try_connect(name: &str) -> Option<Connection> {
     ns::try_connect_with_name(name)
 }
 
-static NAME_SERVER_CONNECTION: AtomicU32 = AtomicU32::new(0);
+static NAME_SERVER_CONNECTION: Atomic<u32> = AtomicU32::new(0);
 
 /// Returns a `Connection` to the name server. If the name server has not been started,
 /// then this call will block until the name server has been started. The `Connection`

library/std/src/os/xous/services/dns.rs

@@ -1,4 +1,4 @@
-use core::sync::atomic::{AtomicU32, Ordering};
+use core::sync::atomic::{Atomic, AtomicU32, Ordering};
 
 use crate::os::xous::ffi::Connection;
 use crate::os::xous::services::connect;
@@ -17,7 +17,7 @@ impl Into<usize> for DnsLendMut {
 /// Returns a `Connection` to the DNS lookup server. This server is used for
 /// querying domain name values.
 pub(crate) fn dns_server() -> Connection {
-    static DNS_CONNECTION: AtomicU32 = AtomicU32::new(0);
+    static DNS_CONNECTION: Atomic<u32> = AtomicU32::new(0);
     let cid = DNS_CONNECTION.load(Ordering::Relaxed);
     if cid != 0 {
         return cid.into();

library/std/src/os/xous/services/log.rs

@@ -1,4 +1,4 @@
-use core::sync::atomic::{AtomicU32, Ordering};
+use core::sync::atomic::{Atomic, AtomicU32, Ordering};
 
 use crate::os::xous::ffi::Connection;
 
@@ -64,7 +64,7 @@ impl Into<usize> for LogLend {
 /// running. It is safe to call this multiple times, because the address is
 /// shared among all threads in a process.
 pub(crate) fn log_server() -> Connection {
-    static LOG_SERVER_CONNECTION: AtomicU32 = AtomicU32::new(0);
+    static LOG_SERVER_CONNECTION: Atomic<u32> = AtomicU32::new(0);
 
     let cid = LOG_SERVER_CONNECTION.load(Ordering::Relaxed);
     if cid != 0 {

library/std/src/os/xous/services/net.rs

@@ -1,4 +1,4 @@
-use core::sync::atomic::{AtomicU32, Ordering};
+use core::sync::atomic::{Atomic, AtomicU32, Ordering};
 
 use crate::os::xous::ffi::Connection;
 use crate::os::xous::services::connect;
@@ -84,7 +84,7 @@ impl<'a> Into<[usize; 5]> for NetBlockingScalar {
 /// Returns a `Connection` to the Network server. This server provides all
 /// OS-level networking functions.
 pub(crate) fn net_server() -> Connection {
-    static NET_CONNECTION: AtomicU32 = AtomicU32::new(0);
+    static NET_CONNECTION: Atomic<u32> = AtomicU32::new(0);
     let cid = NET_CONNECTION.load(Ordering::Relaxed);
     if cid != 0 {
         return cid.into();

library/std/src/os/xous/services/systime.rs

@@ -1,4 +1,4 @@
-use core::sync::atomic::{AtomicU32, Ordering};
+use core::sync::atomic::{Atomic, AtomicU32, Ordering};
 
 use crate::os::xous::ffi::{Connection, connect};
 
@@ -17,7 +17,7 @@ impl Into<[usize; 5]> for SystimeScalar {
 /// Returns a `Connection` to the systime server. This server is used for reporting the
 /// realtime clock.
 pub(crate) fn systime_server() -> Connection {
-    static SYSTIME_SERVER_CONNECTION: AtomicU32 = AtomicU32::new(0);
+    static SYSTIME_SERVER_CONNECTION: Atomic<u32> = AtomicU32::new(0);
     let cid = SYSTIME_SERVER_CONNECTION.load(Ordering::Relaxed);
     if cid != 0 {
         return cid.into();

library/std/src/os/xous/services/ticktimer.rs

@@ -1,4 +1,4 @@
-use core::sync::atomic::{AtomicU32, Ordering};
+use core::sync::atomic::{Atomic, AtomicU32, Ordering};
 
 use crate::os::xous::ffi::Connection;
 
@@ -31,7 +31,7 @@ impl Into<[usize; 5]> for TicktimerScalar {
 /// Returns a `Connection` to the ticktimer server. This server is used for synchronization
 /// primitives such as sleep, Mutex, and Condvar.
 pub(crate) fn ticktimer_server() -> Connection {
-    static TICKTIMER_SERVER_CONNECTION: AtomicU32 = AtomicU32::new(0);
+    static TICKTIMER_SERVER_CONNECTION: Atomic<u32> = AtomicU32::new(0);
     let cid = TICKTIMER_SERVER_CONNECTION.load(Ordering::Relaxed);
     if cid != 0 {
         return cid.into();

library/std/src/panic.rs

@@ -3,7 +3,7 @@
 #![stable(feature = "std_panic", since = "1.9.0")]
 
 use crate::any::Any;
-use crate::sync::atomic::{AtomicU8, Ordering};
+use crate::sync::atomic::{Atomic, AtomicU8, Ordering};
 use crate::sync::{Condvar, Mutex, RwLock};
 use crate::thread::Result;
 use crate::{collections, fmt, panicking};
@@ -466,7 +466,7 @@ impl BacktraceStyle {
 // that backtrace.
 //
 // Internally stores equivalent of an Option<BacktraceStyle>.
-static SHOULD_CAPTURE: AtomicU8 = AtomicU8::new(0);
+static SHOULD_CAPTURE: Atomic<u8> = AtomicU8::new(0);
 
 /// Configures whether the default panic hook will capture and display a
 /// backtrace.

library/std/src/panicking.rs

@@ -21,7 +21,7 @@ use crate::any::Any;
 use crate::io::try_set_output_capture;
 use crate::mem::{self, ManuallyDrop};
 use crate::panic::{BacktraceStyle, PanicHookInfo};
-use crate::sync::atomic::{AtomicBool, Ordering};
+use crate::sync::atomic::{Atomic, AtomicBool, Ordering};
 use crate::sync::{PoisonError, RwLock};
 use crate::sys::backtrace;
 use crate::sys::stdio::panic_output;
@@ -287,7 +287,7 @@ fn default_hook(info: &PanicHookInfo<'_>) {
             };
         });
 
-        static FIRST_PANIC: AtomicBool = AtomicBool::new(true);
+        static FIRST_PANIC: Atomic<bool> = AtomicBool::new(true);
 
         match backtrace {
             // SAFETY: we took out a lock just a second ago.
@@ -372,7 +372,7 @@ pub mod panic_count {
 #[unstable(feature = "update_panic_count", issue = "none")]
 pub mod panic_count {
     use crate::cell::Cell;
-    use crate::sync::atomic::{AtomicUsize, Ordering};
+    use crate::sync::atomic::{Atomic, AtomicUsize, Ordering};
 
     const ALWAYS_ABORT_FLAG: usize = 1 << (usize::BITS - 1);
 
@@ -414,7 +414,7 @@ pub mod panic_count {
     //
     // Stealing a bit is fine because it just amounts to assuming that each
     // panicking thread consumes at least 2 bytes of address space.
-    static GLOBAL_PANIC_COUNT: AtomicUsize = AtomicUsize::new(0);
+    static GLOBAL_PANIC_COUNT: Atomic<usize> = AtomicUsize::new(0);
 
     // Increases the global and local panic count, and returns whether an
     // immediate abort is required.

library/std/src/sync/mpmc/array.rs

@@ -16,13 +16,13 @@ use super::waker::SyncWaker;
 use crate::cell::UnsafeCell;
 use crate::mem::MaybeUninit;
 use crate::ptr;
-use crate::sync::atomic::{self, AtomicUsize, Ordering};
+use crate::sync::atomic::{self, Atomic, AtomicUsize, Ordering};
 use crate::time::Instant;
 
 /// A slot in a channel.
 struct Slot<T> {
     /// The current stamp.
-    stamp: AtomicUsize,
+    stamp: Atomic<usize>,
 
     /// The message in this slot. Either read out in `read` or dropped through
     /// `discard_all_messages`.
@@ -55,7 +55,7 @@ pub(crate) struct Channel<T> {
     /// represent the lap. The mark bit in the head is always zero.
     ///
     /// Messages are popped from the head of the channel.
-    head: CachePadded<AtomicUsize>,
+    head: CachePadded<Atomic<usize>>,
 
     /// The tail of the channel.
     ///
@@ -64,7 +64,7 @@ pub(crate) struct Channel<T> {
     /// represent the lap. The mark bit indicates that the channel is disconnected.
     ///
     /// Messages are pushed into the tail of the channel.
-    tail: CachePadded<AtomicUsize>,
+    tail: CachePadded<Atomic<usize>>,
 
     /// The buffer holding slots.
     buffer: Box<[Slot<T>]>,

library/std/src/sync/mpmc/context.rs

@@ -5,7 +5,7 @@ use super::waker::current_thread_id;
 use crate::cell::Cell;
 use crate::ptr;
 use crate::sync::Arc;
-use crate::sync::atomic::{AtomicPtr, AtomicUsize, Ordering};
+use crate::sync::atomic::{Atomic, AtomicPtr, AtomicUsize, Ordering};
 use crate::thread::{self, Thread};
 use crate::time::Instant;
 
@@ -19,10 +19,10 @@ pub struct Context {
 #[derive(Debug)]
 struct Inner {
     /// Selected operation.
-    select: AtomicUsize,
+    select: Atomic<usize>,
 
     /// A slot into which another thread may store a pointer to its `Packet`.
-    packet: AtomicPtr<()>,
+    packet: Atomic<*mut ()>,
 
     /// Thread handle.
     thread: Thread,

library/std/src/sync/mpmc/counter.rs

@@ -1,16 +1,16 @@
-use crate::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use crate::sync::atomic::{Atomic, AtomicBool, AtomicUsize, Ordering};
 use crate::{ops, process};
 
 /// Reference counter internals.
 struct Counter<C> {
     /// The number of senders associated with the channel.
-    senders: AtomicUsize,
+    senders: Atomic<usize>,
 
     /// The number of receivers associated with the channel.
-    receivers: AtomicUsize,
+    receivers: Atomic<usize>,
 
     /// Set to `true` if the last sender or the last receiver reference deallocates the channel.
-    destroy: AtomicBool,
+    destroy: Atomic<bool>,
 
     /// The internal channel.
     chan: C,

library/std/src/sync/mpmc/list.rs

@@ -9,7 +9,7 @@ use crate::cell::UnsafeCell;
 use crate::marker::PhantomData;
 use crate::mem::MaybeUninit;
 use crate::ptr;
-use crate::sync::atomic::{self, AtomicPtr, AtomicUsize, Ordering};
+use crate::sync::atomic::{self, Atomic, AtomicPtr, AtomicUsize, Ordering};
 use crate::time::Instant;
 
 // Bits indicating the state of a slot:
@@ -37,7 +37,7 @@ struct Slot<T> {
     msg: UnsafeCell<MaybeUninit<T>>,
 
     /// The state of the slot.
-    state: AtomicUsize,
+    state: Atomic<usize>,
 }
 
 impl<T> Slot<T> {
@@ -55,7 +55,7 @@ impl<T> Slot<T> {
 /// Each block in the list can hold up to `BLOCK_CAP` messages.
 struct Block<T> {
     /// The next block in the linked list.
-    next: AtomicPtr<Block<T>>,
+    next: Atomic<*mut Block<T>>,
 
     /// Slots for messages.
     slots: [Slot<T>; BLOCK_CAP],
@@ -65,11 +65,11 @@ impl<T> Block<T> {
     /// Creates an empty block.
     fn new() -> Box<Block<T>> {
         // SAFETY: This is safe because:
-        //  [1] `Block::next` (AtomicPtr) may be safely zero initialized.
+        //  [1] `Block::next` (Atomic<*mut _>) may be safely zero initialized.
         //  [2] `Block::slots` (Array) may be safely zero initialized because of [3, 4].
         //  [3] `Slot::msg` (UnsafeCell) may be safely zero initialized because it
         //       holds a MaybeUninit.
-        //  [4] `Slot::state` (AtomicUsize) may be safely zero initialized.
+        //  [4] `Slot::state` (Atomic<usize>) may be safely zero initialized.
         unsafe { Box::new_zeroed().assume_init() }
     }
 
@@ -110,10 +110,10 @@ impl<T> Block<T> {
 #[derive(Debug)]
 struct Position<T> {
     /// The index in the channel.
-    index: AtomicUsize,
+    index: Atomic<usize>,
 
     /// The block in the linked list.
-    block: AtomicPtr<Block<T>>,
+    block: Atomic<*mut Block<T>>,
 }
 
 /// The token type for the list flavor.