genericCpuAndNativeFeatures

If the fine-grained detection of CPU features via Win registry fails, we fallback to a generic CPU model but we override the feature set using SharedUserData contents. This is effectively what LLVM does for all ARM chips on Windows.

Function parameters

Parameters

arch:Target.Cpu.Arch

Type definitions in this namespace

Types

WindowsVersion
PF
REG

Functions in this namespace

Functions

IsProcessorFeaturePresent
detectRuntimeVersion: Returns the highest known WindowsVersion deduced from reported runtime information.
detectNativeCpuAndFeatures

Source

Implementation

fn genericCpuAndNativeFeatures(arch: Target.Cpu.Arch) Target.Cpu {
    var cpu = Target.Cpu{
        .arch = arch,
        .model = Target.Cpu.Model.generic(arch),
        .features = Target.Cpu.Feature.Set.empty,
    };

    switch (arch) {
        .aarch64, .aarch64_be => {
            const Feature = Target.aarch64.Feature;

            // Override any features that are either present or absent
            setFeature(Feature, &cpu, .neon, IsProcessorFeaturePresent(PF.ARM_NEON_INSTRUCTIONS_AVAILABLE));
            setFeature(Feature, &cpu, .crc, IsProcessorFeaturePresent(PF.ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE));
            setFeature(Feature, &cpu, .crypto, IsProcessorFeaturePresent(PF.ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE));
            setFeature(Feature, &cpu, .lse, IsProcessorFeaturePresent(PF.ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE));
            setFeature(Feature, &cpu, .dotprod, IsProcessorFeaturePresent(PF.ARM_V82_DP_INSTRUCTIONS_AVAILABLE));
            setFeature(Feature, &cpu, .jsconv, IsProcessorFeaturePresent(PF.ARM_V83_JSCVT_INSTRUCTIONS_AVAILABLE));
        },
        else => {},
    }

    return cpu;
}