Support Arm64EC

Author: taiki-e

README.md

@@ -18,7 +18,7 @@ This crate provides a way to soundly perform such operations.
 
 ## Platform Support
 
-Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, PowerPC, s390x, MSP430, AVR, and Hexagon are supported.
+Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, PowerPC, s390x, MSP430, Arm64EC, AVR, and Hexagon are supported.
 
 | target_arch                      | primitives                                          | load/store | swap/CAS |
 | -------------------------------- | --------------------------------------------------- |:----------:|:--------:|
@@ -38,6 +38,7 @@ Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, Power
 | powerpc64 (pwr8+) \[4] \[6]      | i128,u128                                           | ✓          | ✓        |
 | s390x \[4]                       | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128 | ✓          | ✓        |
 | msp430 \[4]                      | isize,usize,i8,u8,i16,u16                           | ✓          |          |
+| arm64ec \[4] (experimental)      | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128 | ✓          | ✓        |
 | avr \[4] (experimental)          | isize,usize,i8,u8,i16,u16                           | ✓          | ✓        |
 | hexagon \[4] (experimental)      | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64           | ✓          | ✓        |
 

build.rs

@@ -62,8 +62,8 @@ fn main() {
                 println!("cargo:rustc-cfg=atomic_maybe_uninit_no_loongarch64_asm");
             }
         }
-        "avr" | "hexagon" | "mips" | "mips32r6" | "mips64" | "mips64r6" | "msp430" | "powerpc"
-        | "powerpc64" => {
+        "arm64ec" | "avr" | "hexagon" | "mips" | "mips32r6" | "mips64" | "mips64r6" | "msp430"
+        | "powerpc" | "powerpc64" => {
             if version.nightly && is_allowed_feature("asm_experimental_arch") {
                 println!("cargo:rustc-cfg=atomic_maybe_uninit_unstable_asm_experimental_arch");
             }
@@ -103,7 +103,7 @@ fn main() {
             // cmpxchg16b_target_feature stabilized in Rust 1.69.
             target_feature_if("cmpxchg16b", has_cmpxchg16b, &version, Stable(69));
         }
-        "aarch64" => {
+        "aarch64" | "arm64ec" => {
             // AArch64 macOS always supports FEAT_LSE/FEAT_LSE2/FEAT_LRCPC because it is ARMv8.5-A:
             // https://github.com/llvm/llvm-project/blob/llvmorg-18.1.2/llvm/include/llvm/TargetParser/AArch64TargetParser.h#L728
             let mut has_lse = is_macos;

src/arch/mod.rs

@@ -27,6 +27,7 @@
     target_arch = "loongarch64",
     all(
         any(
+            target_arch = "arm64ec",
             target_arch = "avr",
             target_arch = "hexagon",
             target_arch = "mips",
@@ -44,7 +45,10 @@
 #[path = "cfgs/unsupported.rs"]
 mod unsupported;
 
-#[cfg(target_arch = "aarch64")]
+#[cfg(any(
+    target_arch = "aarch64",
+    all(target_arch = "arm64ec", atomic_maybe_uninit_unstable_asm_experimental_arch),
+))]
 mod aarch64;
 #[cfg(target_arch = "arm")]
 #[cfg(all(

src/lib.rs

@@ -12,7 +12,7 @@ This crate provides a way to soundly perform such operations.
 
 ## Platform Support
 
-Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, PowerPC, s390x, MSP430, AVR, and Hexagon are supported.
+Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, PowerPC, s390x, MSP430, Arm64EC, AVR, and Hexagon are supported.
 
 | target_arch                      | primitives                                          | load/store | swap/CAS |
 | -------------------------------- | --------------------------------------------------- |:----------:|:--------:|
@@ -32,6 +32,7 @@ Currently, x86, x86_64, ARM, AArch64, RISC-V, LoongArch64, MIPS32, MIPS64, Power
 | powerpc64 (pwr8+) \[4] \[6]      | i128,u128                                           | ✓          | ✓        |
 | s390x \[4]                       | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128 | ✓          | ✓        |
 | msp430 \[4]                      | isize,usize,i8,u8,i16,u16                           | ✓          |          |
+| arm64ec \[4] (experimental)      | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64,i128,u128 | ✓          | ✓        |
 | avr \[4] (experimental)          | isize,usize,i8,u8,i16,u16                           | ✓          | ✓        |
 | hexagon \[4] (experimental)      | isize,usize,i8,u8,i16,u16,i32,u32,i64,u64           | ✓          | ✓        |
 

src/tests/helper.rs

@@ -152,7 +152,7 @@ macro_rules! __test_atomic {
                 #[allow(clippy::ptr_as_ptr)]
                 if core::mem::size_of::<$int_type>() <= core::mem::size_of::<usize>()
                     || cfg!(all(
-                        target_arch = "aarch64",
+                        any(target_arch = "aarch64", target_arch = "arm64ec"),
                         any(target_feature = "lse2", atomic_maybe_uninit_target_feature = "lse2"),
                     ))
                     || cfg!(all(

src/utils.rs

@@ -170,6 +170,7 @@ zero_extend!(i32, u32, i64, u64, isize, usize);
 #[allow(dead_code)]
 #[cfg(any(
     target_arch = "aarch64",
+    target_arch = "arm64ec",
     target_arch = "powerpc64",
     target_arch = "s390x",
     target_arch = "x86_64",
@@ -203,11 +204,21 @@ pub(crate) union MaybeUninit64 {
 #[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 = "arm64ec",
+        target_arch = "arm",
+    ))]
     pub(crate) lo: MaybeUninit<T>,
     pub(crate) hi: MaybeUninit<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 = "arm64ec",
+        target_arch = "arm",
+    )))]
     pub(crate) lo: MaybeUninit<T>,
 }
 

tools/build.sh

@@ -120,6 +120,10 @@ default_targets=(
     # rustc --print target-list | grep -E '^msp430'
     msp430-none-elf
 
+    # arm64ec
+    # rustc --print target-list | grep -E '^arm64ec'
+    arm64ec-pc-windows-msvc
+
     # avr
     # rustc --print target-list | grep -E '^avr'
     avr-unknown-gnu-atmega2560 # custom target