How to print enabled cpu target features in Rust

main.rs

#![recursion_limit="512"]

// This script prints all cpu features which active in this build.
// There are 3 steps in usage of script:
// 1. get list of features using `rustc --print target-features`
// 2. put it into script (it has values actual for 2020-12-06 for x86-64 target).
// 3. run script.

fn pad_name(s: &str)->String{
    let mut res = s.to_string();
    while res.len() < 30 {res.push(' ');}
    res
}

macro_rules! print_if_feature_enabled {
    () => {};
    ($feature:literal $(, $feats:literal)*)=>{
        if cfg!(target_feature = $feature){
            println!("feature {}", pad_name($feature));
        }
        print_if_feature_enabled!($($feats),*)
    }
}

fn main() {
    print_if_feature_enabled!(
        "16bit-mode",
        "32bit-mode",
        "3dnow",
        "3dnowa",
        "64bit",
        "64bit-mode",
        "adx",
        "aes",
        "amx-bf16",
        "amx-int8",
        "amx-tile",
        "avx",
        "avx2",
        "avx512bf16",
        "avx512bitalg",
        "avx512bw",
        "avx512cd",
        "avx512dq",
        "avx512er",
        "avx512f",
        "avx512ifma",
        "avx512pf",
        "avx512vbmi",
        "avx512vbmi2",
        "avx512vl",
        "avx512vnni",
        "avx512vp2intersect",
        "avx512vpopcntdq",
        "bmi",
        "bmi2",
        "branchfusion",
        "cldemote",
        "clflushopt",
        "clwb",
        "clzero",
        "cmov",
        "cx16",
        "cx8",
        "enqcmd",
        "ermsb",
        "f16c",
        "false-deps-lzcnt-tzcnt",
        "false-deps-popcnt",
        "fast-11bytenop",
        "fast-15bytenop",
        "fast-7bytenop",
        "fast-bextr",
        "fast-gather",
        "fast-hops",
        "fast-lzcnt",
        "fast-scalar-fsqrt",
        "fast-scalar-shift-masks",
        "fast-shld-rotate",
        "fast-variable-shuffle",
        "fast-vector-fsqrt",
        "fast-vector-shift-masks",
        "fma",
        "fma4",
        "fsgsbase",
        "fxsr",
        "gfni",
        "idivl-to-divb",
        "idivq-to-divl",
        "invpcid",
        "lea-sp",
        "lea-uses-ag",
        "lvi-cfi",
        "lvi-load-hardening",
        "lwp",
        "lzcnt",
        "macrofusion",
        "merge-to-threeway-branch",
        "mmx",
        "movbe",
        "movdir64b",
        "movdiri",
        "mpx",
        "mwaitx",
        "nopl",
        "pad-short-functions",
        "pclmul",
        "pconfig",
        "pku",
        "popcnt",
        "prefer-128-bit",
        "prefer-256-bit",
        "prefer-mask-registers",
        "prefetchwt1",
        "prfchw",
        "ptwrite",
        "rdpid",
        "rdrnd",
        "rdseed",
        "retpoline",
        "retpoline-external-thunk",
        "retpoline-indirect-branches",
        "retpoline-indirect-calls",
        "rtm",
        "sahf",
        "serialize",
        "seses",
        "sgx",
        "sha",
        "shstk",
        "slow-3ops-lea",
        "slow-incdec",
        "slow-lea",
        "slow-pmaddwd",
        "slow-pmulld",
        "slow-shld",
        "slow-two-mem-ops",
        "slow-unaligned-mem-16",
        "slow-unaligned-mem-32",
        "soft-float",
        "sse",
        "sse-unaligned-mem",
        "sse2",
        "sse3",
        "sse4.1",
        "sse4.2",
        "sse4a",
        "ssse3",
        "tbm",
        "tsxldtrk",
        "use-aa",
        "use-glm-div-sqrt-costs",
        "vaes",
        "vpclmulqdq",
        "vzeroupper",
        "waitpkg",
        "wbnoinvd",
        "x87",
        "xop",
        "xsave",
        "xsavec",
        "xsaveopt",
        "xsaves"
    );
}

An alternative to this script is running

rustc --print=cfg -C target-cpu=skylake

Replace skylake with your target CPU or native.

@strohel Thank you for this, I added this variant to my answer in stackoverflow.
https://stackoverflow.com/a/65163535/8195987

Perfect, I upvoted your question and answer.

Thanks, this is very useful.

I would like to publish a crate with a function that returns the currently enabled features: pub fn target_features() -> Vec<String>. My draft is here. Would it be OK to publish under the Apache2/MIT licenses? Any comments or suggestions?

@astraw Yes, you can publish it. Just include reference about my code into yours.

My only concern is list of features can became obsolete when compiler updates. Maybe you would generate list of features to test using build.rs?

Thanks.

Now that I waited so long, it someone already made this into a crate called target. The target::features function is the relevant one. :)