Run-time feature detection for Aarch64 on Windows.

Author: makotokato

crates/std_detect/Cargo.toml

@@ -25,6 +25,9 @@ maintenance = { status = "experimental" }
 libc = { version = "0.2", optional = true, default-features = false }
 cfg-if = "0.1.10"
 
+[target.'cfg(target_os="windows")'.dependencies]
+winapi = {version = "0.3.8", features = ["processthreadsapi"]}
+
 [dev-dependencies]
 auxv = "0.3.3"
 cupid = "0.6.0"

crates/std_detect/src/detect/mod.rs

@@ -106,6 +106,9 @@ cfg_if! {
         mod aarch64;
         #[path = "os/freebsd/mod.rs"]
         mod os;
+    } else if #[cfg(all(target_os = "windows", target_arch = "aarch64"))] {
+        #[path = "os/windows/aarch64.rs"]
+        mod os;
     } else {
         #[path = "os/other.rs"]
         mod os;

crates/std_detect/src/detect/os/windows/aarch64.rs

@@ -0,0 +1,30 @@
+//! Run-time feature detection for Aarch64 on Windows.
+
+use crate::detect::{cache, Feature};
+use winapi::um::processthreadsapi::IsProcessorFeaturePresent;
+use winapi::um::winnt::*;
+
+/// Try to read the features from OS API.
+pub(crate) fn detect_features() -> cache::Initializer {
+    let mut value = cache::Initializer::default();
+    {
+        let mut enable_feature = |f, enable| {
+            if enable {
+                value.set(f as u32);
+            }
+        };
+        enable_feature(Feature::asimd, unsafe {
+            IsProcessorFeaturePresent(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE) != 0
+        });
+        enable_feature(Feature::crc, unsafe {
+            IsProcessorFeaturePresent(PF_ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE) != 0
+        });
+        enable_feature(Feature::crypto, unsafe {
+            IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE) != 0
+        });
+        enable_feature(Feature::pmull, unsafe {
+            IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE) != 0
+        });
+    }
+    value
+}