build.rs

use std::env;
use std::path::PathBuf;
use std::process::Command;

fn aarch64_vfp_compile() {
    // 获取当前 crate 输出目录
    let out_dir = env::var("OUT_DIR").unwrap();
    // 指定汇编文件路径
    let asm_file = PathBuf::from("src/arch/vfp.S");
    let asm_out_file = PathBuf::from(&out_dir).join("vfp.o");

    // 编译汇编文件，增加 target-feature 选项
    let status = Command::new("clang")
        .args([
            "-c",
            asm_file.to_str().unwrap(),
            "-o",
            asm_out_file.to_str().unwrap(),
            "-target",
            "aarch64-unknown-none",
            "-mfpu=neon",
        ])
        .status()
        .expect("failed to execute clang");
    assert!(status.success(), "clang failed to compile assembly file");

    // 打包对象文件为静态库
    let lib_out_file = PathBuf::from(&out_dir).join("libvfp.a");
    let status = Command::new("ar")
        .args([
            "crus",
            lib_out_file.to_str().unwrap(),
            asm_out_file.to_str().unwrap(),
        ])
        .status()
        .expect("failed to execute ar");
    assert!(status.success(), "ar failed to create static library");

    // 指示 rustc 链接器链接汇编对象文件
    println!("cargo:rerun-if-changed=src/arch/vfp.S");
    println!("cargo:rustc-link-search={}", out_dir);
    println!("cargo:rustc-link-lib=static=vfp");
}

fn main() {
    let arch = std::env::var("CARGO_CFG_TARGET_ARCH").unwrap();
    if arch == "aarch64" {
        aarch64_vfp_compile();
    }
}