arm64ec: Support 128-bit atomics

README.md

@@ -52,7 +52,7 @@ portable-atomic = { version = "1.3", default-features = false, features = ["requ
 
 ## 128-bit atomics support
 
-Native 128-bit atomic operations are available on x86_64 (Rust 1.59+), AArch64 (Rust 1.59+), riscv64 (Rust 1.82+), powerpc64 (nightly only), and s390x (nightly only), otherwise the fallback implementation is used.
+Native 128-bit atomic operations are available on x86_64 (Rust 1.59+), AArch64 (Rust 1.59+), riscv64 (Rust 1.82+), powerpc64 (nightly only), s390x (nightly only), and Arm64EC (nightly only), otherwise the fallback implementation is used.
 
 On x86_64, even if `cmpxchg16b` is not available at compile-time (note: `cmpxchg16b` target feature is enabled by default only on Apple and Windows (except Windows 7) targets), run-time detection checks whether `cmpxchg16b` is available. If `cmpxchg16b` is not available at either compile-time or run-time detection, the fallback implementation is used. See also [`portable_atomic_no_outline_atomics`](#optional-cfg-no-outline-atomics) cfg.
 
@@ -170,7 +170,7 @@ RUSTFLAGS="--cfg portable_atomic_no_outline_atomics" cargo ...
   If dynamic dispatching by run-time CPU feature detection is enabled, it allows maintaining support for older CPUs while using features that are not supported on older CPUs, such as CMPXCHG16B (x86_64) and FEAT_LSE/FEAT_LSE2 (AArch64).
 
   Note:
-  - Dynamic detection is currently only enabled in Rust 1.59+ for x86_64 and AArch64, nightly only for powerpc64 (disabled by default), otherwise it works the same as when this cfg is set.
+  - Dynamic detection is currently only enabled in Rust 1.59+ for x86_64 and AArch64, Rust 1.82+ for RISC-V (disabled by default), nightly only for powerpc64 (disabled by default) and Arm64EC, otherwise it works the same as when this cfg is set.
   - If the required target features are enabled at compile-time, the atomic operations are inlined.
   - This is compatible with no-std (as with all features except `std`).
   - On some targets, run-time detection is disabled by default mainly for compatibility with older versions of operating systems or incomplete build environments, and can be enabled by `--cfg portable_atomic_outline_atomics`. (When both cfg are enabled, `*_no_*` cfg is preferred.)

bench/benches/bench.rs

@@ -35,7 +35,10 @@ mod tests {
 #[allow(dead_code, unused_imports)]
 #[path = "../../src/imp/mod.rs"]
 mod imp;
-#[cfg(any(target_arch = "x86_64", all(target_arch = "aarch64", target_endian = "little")))]
+#[cfg(any(
+    target_arch = "x86_64",
+    all(any(target_arch = "aarch64", target_arch = "arm64ec"), target_endian = "little")
+))]
 #[allow(dead_code, unused_imports)]
 #[path = "../../src/imp/atomic128/intrinsics.rs"]
 mod intrinsics;
@@ -343,21 +346,28 @@ macro_rules! benches {
 #[cfg(any(
     target_arch = "x86_64",
     target_arch = "aarch64",
+    target_arch = "arm64ec",
     target_arch = "powerpc64",
     target_arch = "s390x",
 ))]
 mod bench {
     use super::*;
 
-    #[cfg(any(target_arch = "x86_64", all(target_arch = "aarch64", target_endian = "little")))]
+    #[cfg(any(
+        target_arch = "x86_64",
+        all(any(target_arch = "aarch64", target_arch = "arm64ec"), target_endian = "little")
+    ))]
     impl_atomic!(intrinsics::AtomicU128, u128);
     impl_atomic!(imp::AtomicU128, u128);
     impl_atomic!(seqlock_fallback::AtomicU128, u128);
     impl_atomic!(spinlock_fallback::AtomicU128, u128);
     // impl_atomic!(atomic::Atomic<u128>, u128);
     // impl_atomic_no_order!(crossbeam_utils::atomic::AtomicCell<u128>, u128);
 
-    #[cfg(any(target_arch = "x86_64", all(target_arch = "aarch64", target_endian = "little")))]
+    #[cfg(any(
+        target_arch = "x86_64",
+        all(any(target_arch = "aarch64", target_arch = "arm64ec"), target_endian = "little")
+    ))]
     benches!(bench_portable_atomic_intrinsics, intrinsics::AtomicU128, u128);
     benches!(bench_portable_atomic_arch, imp::AtomicU128, u128);
     benches!(bench_portable_atomic_seqlock_fallback, seqlock_fallback::AtomicU128, u128);

build.rs

@@ -195,7 +195,8 @@ fn main() {
         // https://github.com/rust-lang/rust/pull/111331 merged in Rust 1.71 (nightly-2023-05-09).
         if !no_asm
             && (target_arch == "powerpc64" && version.probe(60, 2022, 2, 12)
-                || target_arch == "s390x" && version.probe(71, 2023, 5, 8))
+                || target_arch == "s390x" && version.probe(71, 2023, 5, 8)
+                || target_arch == "arm64ec")
             && is_allowed_feature("asm_experimental_arch")
         {
             println!("cargo:rustc-cfg=portable_atomic_unstable_asm_experimental_arch");
@@ -230,7 +231,7 @@ fn main() {
                 target_feature_fallback("cmpxchg16b", has_cmpxchg16b);
             }
         }
-        "aarch64" => {
+        "aarch64" | "arm64ec" => {
             // For Miri and ThreadSanitizer.
             // https://github.com/rust-lang/rust/pull/97423 merged in Rust 1.64 (nightly-2022-06-30).
             if version.nightly && version.probe(64, 2022, 6, 29) {

src/cfgs.rs

@@ -256,6 +256,7 @@ mod atomic_64_macros {
             target_arch = "aarch64",
             any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
         ),
+        all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch),
         all(
             target_arch = "x86_64",
             not(all(
@@ -362,6 +363,7 @@ mod atomic_128_macros {
             target_arch = "aarch64",
             any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
         ),
+        all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch),
         all(
             target_arch = "x86_64",
             not(all(

src/imp/atomic128/README.md

@@ -9,7 +9,7 @@ Here is the table of targets that support 128-bit atomics and the instructions u
 | target_arch | load | store | CAS | RMW | note |
 | ----------- | ---- | ----- | --- | --- | ---- |
 | x86_64 | cmpxchg16b or vmovdqa | cmpxchg16b or vmovdqa | cmpxchg16b | cmpxchg16b | cmpxchg16b target feature required. vmovdqa requires Intel, AMD, or Zhaoxin CPU with AVX. <br> Both compile-time and run-time detection are supported for cmpxchg16b. vmovdqa is currently run-time detection only. <br> Requires rustc 1.59+ |
-| aarch64 | ldxp/stxp or casp or ldp/ldiapp | ldxp/stxp or casp or stp/stilp/swpp | ldxp/stxp or casp | ldxp/stxp or casp/swpp/ldclrp/ldsetp | casp requires lse target feature, ldp/stp requires lse2 target feature, ldiapp/stilp requires lse2 and rcpc3 target features, swpp/ldclrp/ldsetp requires lse128 target feature. <br> Both compile-time and run-time detection are supported. <br> Requires rustc 1.59+ |
+| aarch64/arm64ec | ldxp/stxp or casp or ldp/ldiapp | ldxp/stxp or casp or stp/stilp/swpp | ldxp/stxp or casp | ldxp/stxp or casp/swpp/ldclrp/ldsetp | casp requires lse target feature, ldp/stp requires lse2 target feature, ldiapp/stilp requires lse2 and rcpc3 target features, swpp/ldclrp/ldsetp requires lse128 target feature. <br> Both compile-time and run-time detection are supported. <br> Requires rustc 1.59+ (aarch64) / nightly (arm64ec) |
 | riscv64 | amocas.q | amocas.q | amocas.q | amocas.q | Experimental because LLVM marking the corresponding target feature as experimental. Requires experimental-zacas target feature. Both compile-time and run-time detection are supported (run-time detection is currently disabled by default). <br> Requires 1.82+ (LLVM 19+) |
 | powerpc64 | lq | stq | lqarx/stqcx. | lqarx/stqcx. | Requires target-cpu pwr8+ (powerpc64le is pwr8 by default). Both compile-time and run-time detection are supported (run-time detection is currently disabled by default). <br> Requires nightly |
 | s390x | lpq | stpq | cdsg | cdsg | Requires nightly |

src/imp/atomic128/mod.rs

@@ -7,9 +7,9 @@ See README.md for details.
 */
 
 // AArch64
-#[cfg(all(
-    target_arch = "aarch64",
-    any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
+#[cfg(any(
+    all(target_arch = "aarch64", any(not(portable_atomic_no_asm), portable_atomic_unstable_asm)),
+    all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch)
 ))]
 // Use intrinsics.rs on Miri and Sanitizer that do not support inline assembly.
 #[cfg_attr(

src/imp/core_atomic.rs

@@ -263,7 +263,7 @@ macro_rules! atomic_int {
                 {
                     #[cfg(any(
                         all(
-                            target_arch = "aarch64",
+                            any(target_arch = "aarch64", target_arch = "arm64ec"),
                             any(target_feature = "lse", portable_atomic_target_feature = "lse"),
                         ),
                         all(
@@ -315,7 +315,7 @@ macro_rules! atomic_int {
                 {
                     #[cfg(any(
                         all(
-                            target_arch = "aarch64",
+                            any(target_arch = "aarch64", target_arch = "arm64ec"),
                             any(target_feature = "lse", portable_atomic_target_feature = "lse"),
                         ),
                         all(

src/imp/detect/README.md

@@ -14,7 +14,7 @@ Here is the table of targets that support run-time CPU feature detection and the
 | aarch64     | openbsd              | sysctl          | all      | Enabled by default |
 | aarch64     | macos/ios/tvos/watchos/visionos | sysctlbyname    | all      | Currently only used in tests (see [aarch64_apple.rs](aarch64_apple.rs)). |
 | aarch64     | illumos              | getisax         | lse, lse2 | Disabled by default |
-| aarch64     | windows              | IsProcessorFeaturePresent | lse | Enabled by default |
+| aarch64/arm64ec | windows              | IsProcessorFeaturePresent | lse | Enabled by default |
 | aarch64     | fuchsia              | zx_system_get_features | lse | Enabled by default |
 | riscv32     | linux                | riscv_hwprobe   | all      | Disabled by default |
 | riscv64     | linux                | riscv_hwprobe   | all      | Disabled by default |

src/imp/detect/common.rs

@@ -69,7 +69,7 @@ macro_rules! flags {
     };
 }
 
-#[cfg(target_arch = "aarch64")]
+#[cfg(any(target_arch = "aarch64", target_arch = "arm64ec"))]
 flags! {
     // FEAT_LSE, Large System Extensions
     // https://developer.arm.com/documentation/109697/0100/Feature-descriptions/The-Armv8-1-architecture-extension
@@ -250,7 +250,7 @@ mod tests_common {
         let _ = stdout.write_all(features.as_bytes());
     }
 
-    #[cfg(target_arch = "aarch64")]
+    #[cfg(any(target_arch = "aarch64", target_arch = "arm64ec"))]
     #[test]
     #[cfg_attr(portable_atomic_test_outline_atomics_detect_false, ignore)]
     fn test_detect() {

src/imp/fallback/utils.rs

@@ -22,7 +22,12 @@ use core::ops;
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_ppc64x.go#L9
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/powerpc/include/asm/cache.h#L26
 #[cfg_attr(
-    any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "powerpc64"),
+    any(
+        target_arch = "x86_64",
+        target_arch = "aarch64",
+        target_arch = "arm64ec",
+        target_arch = "powerpc64",
+    ),
     repr(align(128))
 )]
 // arm, mips, mips64, sparc, and hexagon have 32-byte cache line size.
@@ -70,6 +75,7 @@ use core::ops;
     not(any(
         target_arch = "x86_64",
         target_arch = "aarch64",
+        target_arch = "arm64ec",
         target_arch = "powerpc64",
         target_arch = "arm",
         target_arch = "mips",

src/imp/mod.rs

@@ -76,6 +76,7 @@ mod atomic64;
 // 128-bit atomic implementations on 64-bit architectures
 #[cfg(any(
     target_arch = "aarch64",
+    target_arch = "arm64ec",
     target_arch = "powerpc64",
     target_arch = "riscv64",
     target_arch = "s390x",
@@ -96,6 +97,7 @@ mod atomic128;
             target_arch = "aarch64",
             any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
         ),
+        all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch),
         all(
             target_arch = "x86_64",
             any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
@@ -296,6 +298,7 @@ items! {
             target_arch = "aarch64",
             any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
         ),
+        all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch),
         all(
             target_arch = "x86_64",
             not(all(
@@ -398,9 +401,9 @@ pub(crate) use self::atomic64::riscv32::{AtomicI64, AtomicU64};
 
 // 128-bit atomics (platform-specific)
 // AArch64
-#[cfg(all(
-    target_arch = "aarch64",
-    any(not(portable_atomic_no_asm), portable_atomic_unstable_asm),
+#[cfg(any(
+    all(target_arch = "aarch64", any(not(portable_atomic_no_asm), portable_atomic_unstable_asm)),
+    all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch)
 ))]
 pub(crate) use self::atomic128::aarch64::{AtomicI128, AtomicU128};
 // x86_64 & (cmpxchg16b | outline-atomics)

src/lib.rs

@@ -46,7 +46,7 @@ portable-atomic = { version = "1.3", default-features = false, features = ["requ
 
 ## 128-bit atomics support
 
-Native 128-bit atomic operations are available on x86_64 (Rust 1.59+), AArch64 (Rust 1.59+), riscv64 (Rust 1.82+), powerpc64 (nightly only), and s390x (nightly only), otherwise the fallback implementation is used.
+Native 128-bit atomic operations are available on x86_64 (Rust 1.59+), AArch64 (Rust 1.59+), riscv64 (Rust 1.82+), powerpc64 (nightly only), s390x (nightly only), and Arm64EC (nightly only), otherwise the fallback implementation is used.
 
 On x86_64, even if `cmpxchg16b` is not available at compile-time (note: `cmpxchg16b` target feature is enabled by default only on Apple and Windows (except Windows 7) targets), run-time detection checks whether `cmpxchg16b` is available. If `cmpxchg16b` is not available at either compile-time or run-time detection, the fallback implementation is used. See also [`portable_atomic_no_outline_atomics`](#optional-cfg-no-outline-atomics) cfg.
 
@@ -164,7 +164,7 @@ RUSTFLAGS="--cfg portable_atomic_no_outline_atomics" cargo ...
   If dynamic dispatching by run-time CPU feature detection is enabled, it allows maintaining support for older CPUs while using features that are not supported on older CPUs, such as CMPXCHG16B (x86_64) and FEAT_LSE/FEAT_LSE2 (AArch64).
 
   Note:
-  - Dynamic detection is currently only enabled in Rust 1.59+ for x86_64 and AArch64, nightly only for powerpc64 (disabled by default), otherwise it works the same as when this cfg is set.
+  - Dynamic detection is currently only enabled in Rust 1.59+ for x86_64 and AArch64, Rust 1.82+ for RISC-V (disabled by default), nightly only for powerpc64 (disabled by default) and Arm64EC, otherwise it works the same as when this cfg is set.
   - If the required target features are enabled at compile-time, the atomic operations are inlined.
   - This is compatible with no-std (as with all features except `std`).
   - On some targets, run-time detection is disabled by default mainly for compatibility with older versions of operating systems or incomplete build environments, and can be enabled by `--cfg portable_atomic_outline_atomics`. (When both cfg are enabled, `*_no_*` cfg is preferred.)
@@ -215,7 +215,7 @@ RUSTFLAGS="--cfg portable_atomic_no_outline_atomics" cargo ...
 #![allow(clippy::inline_always)]
 // asm_experimental_arch
 // AVR, MSP430, and Xtensa are tier 3 platforms and require nightly anyway.
-// On tier 2 platforms (powerpc64 and s390x), we use cfg set by build script to
+// On tier 2 platforms (arm64ec, powerpc64, and s390x), we use cfg set by build script to
 // determine whether this feature is available or not.
 #![cfg_attr(
     all(
@@ -224,6 +224,7 @@ RUSTFLAGS="--cfg portable_atomic_no_outline_atomics" cargo ...
             target_arch = "avr",
             target_arch = "msp430",
             all(target_arch = "xtensa", portable_atomic_unsafe_assume_single_core),
+            all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch),
             all(target_arch = "powerpc64", portable_atomic_unstable_asm_experimental_arch),
             all(target_arch = "s390x", portable_atomic_unstable_asm_experimental_arch),
         ),
@@ -277,6 +278,7 @@ RUSTFLAGS="--cfg portable_atomic_no_outline_atomics" cargo ...
     all(
         any(
             target_arch = "aarch64",
+            target_arch = "arm64ec",
             target_arch = "powerpc64",
             target_arch = "riscv64",
             target_arch = "s390x",
@@ -289,6 +291,7 @@ RUSTFLAGS="--cfg portable_atomic_no_outline_atomics" cargo ...
     all(
         any(
             target_arch = "aarch64",
+            target_arch = "arm64ec",
             target_arch = "powerpc64",
             target_arch = "riscv64",
             target_arch = "s390x",
@@ -358,6 +361,7 @@ compile_error!(
 #[cfg(portable_atomic_no_outline_atomics)]
 #[cfg(not(any(
     target_arch = "aarch64",
+    target_arch = "arm64ec",
     target_arch = "arm",
     target_arch = "powerpc64",
     target_arch = "riscv32",

src/tests/mod.rs

@@ -131,6 +131,7 @@ fn test_is_lock_free() {
         assert!(!AtomicU128::is_lock_free());
     } else if cfg!(any(
         target_arch = "aarch64",
+        all(target_arch = "arm64ec", portable_atomic_unstable_asm_experimental_arch),
         all(
             target_arch = "x86_64",
             any(target_feature = "cmpxchg16b", portable_atomic_target_feature = "cmpxchg16b"),

src/utils.rs

@@ -47,6 +47,7 @@ macro_rules! doc_comment {
 #[cfg(any(
     target_arch = "aarch64",
     target_arch = "arm",
+    target_arch = "arm64ec",
     target_arch = "powerpc64",
     target_arch = "riscv32",
     target_arch = "riscv64",
@@ -82,6 +83,7 @@ macro_rules! ifunc {
 #[cfg(any(
     target_arch = "aarch64",
     target_arch = "arm",
+    target_arch = "arm64ec",
     target_arch = "powerpc64",
     target_arch = "riscv32",
     target_arch = "riscv64",
@@ -347,6 +349,7 @@ pub(crate) fn zero_extend64_ptr(v: *mut ()) -> core::mem::MaybeUninit<u64> {
 #[allow(dead_code)]
 #[cfg(any(
     target_arch = "aarch64",
+    target_arch = "arm64ec",
     target_arch = "powerpc64",
     target_arch = "riscv64",
     target_arch = "s390x",
@@ -379,11 +382,21 @@ pub(crate) union U64 {
 #[repr(C)]
 pub(crate) struct Pair<T: Copy> {
     // little endian order
-    #[cfg(any(target_endian = "little", target_arch = "aarch64", target_arch = "arm"))]
+    #[cfg(any(
+        target_endian = "little",
+        target_arch = "aarch64",
+        target_arch = "arm",
+        target_arch = "arm64ec",
+    ))]
     pub(crate) lo: T,
     pub(crate) hi: T,
     // big endian order
-    #[cfg(not(any(target_endian = "little", target_arch = "aarch64", target_arch = "arm")))]
+    #[cfg(not(any(
+        target_endian = "little",
+        target_arch = "aarch64",
+        target_arch = "arm",
+        target_arch = "arm64ec",
+    )))]
     pub(crate) lo: T,
 }
 

tests/helper/src/cpuinfo.rs

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-#![cfg(any(target_arch = "aarch64", target_arch = "powerpc64"))]
+#![cfg(any(target_arch = "aarch64", target_arch = "arm64ec", target_arch = "powerpc64"))]
 
 use std::{boxed::Box, path::Path, vec::Vec};
 
@@ -17,7 +17,7 @@ type Result<T, E = Box<dyn std::error::Error + Send + Sync>> = std::result::Resu
 /// This is used for testing to ensure that the result of the CPU feature
 /// detection we are using matches the information we get from the other
 /// approaches.
-#[cfg(target_arch = "aarch64")]
+#[cfg(any(target_arch = "aarch64", target_arch = "arm64ec"))]
 #[derive(Debug, Clone, Copy)]
 pub struct ProcCpuinfo {
     pub lse: bool,
@@ -33,7 +33,7 @@ pub struct ProcCpuinfo {
     pub power10: Option<bool>,
 }
 impl ProcCpuinfo {
-    #[cfg(target_arch = "aarch64")]
+    #[cfg(any(target_arch = "aarch64", target_arch = "arm64ec"))]
     pub fn new() -> Result<Self> {
         use std::process::Command;
         if cfg!(any(target_os = "linux", target_os = "android", target_os = "netbsd")) {