windows: detect native CPU features for aarch64 SoCs

2 files changed, 42 insertions, 0 deletions

diff --git a/lib/std/zig/system/NativeTargetInfo.zig b/lib/std/zig/system/NativeTargetInfo.zig
index 09b863cdf7..0232797387 100644
--- a/lib/std/zig/system/NativeTargetInfo.zig
+++ b/lib/std/zig/system/NativeTargetInfo.zig
@@ -978,6 +978,7 @@ fn detectNativeCpuAndFeatures(cpu_arch: Target.Cpu.Arch, os: Target.Os, cross_ta
     switch (builtin.os.tag) {
         .linux => return linux.detectNativeCpuAndFeatures(),
         .macos => return darwin.macos.detectNativeCpuAndFeatures(),
+        .windows => return windows.detectNativeCpuAndFeatures(),
         else => {},
     }
 
diff --git a/lib/std/zig/system/windows.zig b/lib/std/zig/system/windows.zig
index 595dac6278..eb62068120 100644
--- a/lib/std/zig/system/windows.zig
+++ b/lib/std/zig/system/windows.zig
@@ -1,6 +1,10 @@
 const std = @import("std");
+const builtin = @import("builtin");
+const Target = std.Target;
 
 pub const WindowsVersion = std.Target.Os.WindowsVersion;
+pub const PF = std.os.windows.PF;
+pub const IsProcessorFeaturePresent = std.os.windows.IsProcessorFeaturePresent;
 
 /// Returns the highest known WindowsVersion deduced from reported runtime information.
 /// Discards information about in-between versions we don't differentiate.
@@ -38,3 +42,40 @@ pub fn detectRuntimeVersion() WindowsVersion {
 
     return @intToEnum(WindowsVersion, version);
 }
+
+fn detectNativeCpuAndFeaturesArm64() Target.Cpu {
+    const Feature = Target.aarch64.Feature;
+
+    var cpu = Target.Cpu{
+        .arch = .aarch64,
+        .model = Target.Cpu.Model.generic(.aarch64),
+        .features = Target.Cpu.Feature.Set.empty,
+    };
+
+    if (IsProcessorFeaturePresent(PF.ARM_NEON_INSTRUCTIONS_AVAILABLE)) {
+        cpu.features.addFeature(@enumToInt(Feature.neon));
+    }
+    if (IsProcessorFeaturePresent(PF.ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE)) {
+        cpu.features.addFeature(@enumToInt(Feature.crc));
+    }
+    if (IsProcessorFeaturePresent(PF.ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE)) {
+        cpu.features.addFeature(@enumToInt(Feature.crypto));
+    }
+
+    return cpu;
+}
+
+fn getCpuCount() usize {
+    return std.os.windows.peb().NumberOfProcessors;
+}
+
+pub fn detectNativeCpuAndFeatures() ?Target.Cpu {
+    switch (builtin.cpu.arch) {
+        .aarch64 => return detectNativeCpuAndFeaturesArm64(),
+        else => |arch| return .{
+            .arch = arch,
+            .model = Target.Cpu.Model.generic(arch),
+            .features = Target.Cpu.Feature.Set.empty,
+        },
+    }
+}