Remove build-time check for stdsimd feature

This is blocking rust-lang/rust#117372, which replaces `stdsimd` with
more fine-grained features. However the auto-detection in aHash breaks
when bootstrapping Rust because it detects the `stdsimd` feature on the
old toolchain which is not present on the newly build libcore.

This PR removes the build-time detection of the `stdsimd` feature and
instead just uses the ARM AES intrinsics directly since they are now
stable, but only on AArch64.

Author: Amanieu

build.rs

@@ -7,9 +7,6 @@ fn main() {
     if let Some(true) = version_check::supports_feature("specialize") {
         println!("cargo:rustc-cfg=feature=\"specialize\"");
     }
-    if let Some(true) = version_check::supports_feature("stdsimd") {
-        println!("cargo:rustc-cfg=feature=\"stdsimd\"");
-    }
     let arch = env::var("CARGO_CFG_TARGET_ARCH").expect("CARGO_CFG_TARGET_ARCH was not set");
     if arch.eq_ignore_ascii_case("x86_64")
         || arch.eq_ignore_ascii_case("aarch64")

src/hash_quality_test.rs

@@ -437,12 +437,7 @@ mod fallback_tests {
 ///Basic sanity tests of the cypto properties of aHash.
 #[cfg(any(
     all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
-    all(
-        any(target_arch = "arm", target_arch = "aarch64"),
-        any(target_feature = "aes", target_feature = "crypto"),
-        not(miri),
-        feature = "stdsimd"
-    )
+    all(target_arch = "aarch64", target_feature = "aes", not(miri)),
 ))]
 #[cfg(test)]
 mod aes_tests {

src/lib.rs

@@ -95,8 +95,6 @@ Note the import of [HashMapExt]. This is needed for the constructor.
 #![allow(clippy::pedantic, clippy::cast_lossless, clippy::unreadable_literal)]
 #![cfg_attr(all(not(test), not(feature = "std")), no_std)]
 #![cfg_attr(feature = "specialize", feature(min_specialization))]
-#![cfg_attr(feature = "specialize", feature(build_hasher_simple_hash_one))]
-#![cfg_attr(feature = "stdsimd", feature(stdsimd))]
 
 #[macro_use]
 mod convert;
@@ -106,11 +104,8 @@ mod fallback_hash;
 cfg_if::cfg_if! {
     if #[cfg(any(
             all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
-            all(any(target_arch = "arm", target_arch = "aarch64"),
-                any(target_feature = "aes", target_feature = "crypto"),
-                not(miri),
-                feature = "stdsimd")
-            ))] {
+            all(target_arch = "aarch64", target_feature = "aes", not(miri)),
+        ))] {
         mod aes_hash;
         pub use crate::aes_hash::AHasher;
     } else {

src/operations.rs

@@ -110,12 +110,7 @@ pub(crate) fn aesenc(value: u128, xor: u128) -> u128 {
     }
 }
 
-#[cfg(all(
-    any(target_arch = "arm", target_arch = "aarch64"),
-    any(target_feature = "aes", target_feature = "crypto"),
-    not(miri),
-    feature = "stdsimd"
-))]
+#[cfg(all(target_arch = "aarch64", target_feature = "aes", not(miri)))]
 #[allow(unused)]
 #[inline(always)]
 pub(crate) fn aesenc(value: u128, xor: u128) -> u128 {
@@ -142,12 +137,7 @@ pub(crate) fn aesdec(value: u128, xor: u128) -> u128 {
     }
 }
 
-#[cfg(all(
-    any(target_arch = "arm", target_arch = "aarch64"),
-    any(target_feature = "aes", target_feature = "crypto"),
-    not(miri),
-    feature = "stdsimd"
-))]
+#[cfg(all(target_arch = "aarch64", target_feature = "aes", not(miri)))]
 #[allow(unused)]
 #[inline(always)]
 pub(crate) fn aesdec(value: u128, xor: u128) -> u128 {

src/random_state.rs

@@ -2,7 +2,7 @@ use core::hash::Hash;
 cfg_if::cfg_if! {
     if #[cfg(any(
         all(any(target_arch = "x86", target_arch = "x86_64"), target_feature = "aes", not(miri)),
-         all(any(target_arch = "arm", target_arch = "aarch64"), any(target_feature = "aes", target_feature = "crypto"), not(miri), feature = "stdsimd")
+        all(target_arch = "aarch64", target_feature = "aes", not(miri)),
     ))] {
         use crate::aes_hash::*;
     } else {

tests/bench.rs

@@ -14,12 +14,7 @@ const AHASH_IMPL: &str = if cfg!(any(
         target_feature = "aes",
         not(miri),
     ),
-    all(
-        any(target_arch = "arm", target_arch = "aarch64"),
-        any(target_feature = "aes", target_feature = "crypto"),
-        not(miri),
-        feature = "stdsimd",
-    ),
+    all(target_arch = "aarch64", target_feature = "aes", not(miri)),
 )) {
     "aeshash"
 } else {