mu_lib 0.2.0

XCENA mu Library
use std::env;

fn main() {
    let llvm_path =
        env::var("MU_LLVM_PATH").unwrap_or("/usr/local/mu_library/mu_llvm/llvm-18.1".to_string());
    let mu_lib_path = env::var("MU_LIB_PATH").unwrap_or("/usr/local/mu_library/mu/".to_string());

    eprintln!("[mu_lib build.rs] Build script executing...");
    eprintln!("[mu_lib build.rs] LLVM path: {}", llvm_path);
    eprintln!("[mu_lib build.rs] MU library path: {}", mu_lib_path);

    println!("cargo:rerun-if-changed=src");

    // Set linker
    let linker_path = format!("{}/bin/ld.lld", llvm_path);
    println!("cargo:rustc-linker={}", linker_path);
    eprintln!("[mu_lib build.rs] Linker path: {}", linker_path);

    let builtins_rv_path = format!("{}/builtins-rv", llvm_path);
    println!("cargo:rustc-link-search={}", builtins_rv_path);
    println!("cargo:rustc-link-lib=clang_rt.builtins-riscv64");

    // Set linker script
    let linker_script_path = format!("{}/script/mu_linker.ld", mu_lib_path);
    println!("cargo:rustc-link-args=-T{}", linker_script_path);
    eprintln!(
        "[mu_lib build.rs] Linker script path: {}",
        linker_script_path
    );

    // Set library path
    let picolibc_newlib_path = format!("{}/picolibc-rv/newlib", llvm_path);
    println!("cargo:rustc-link-search={}", picolibc_newlib_path);
    eprintln!("[mu_lib build.rs] Picolibc path: {}", picolibc_newlib_path);

    let mu_lib_search_path = format!("{}/lib", mu_lib_path);
    println!("cargo:rustc-link-search={}", mu_lib_search_path);
    eprintln!(
        "[mu_lib build.rs] MU library search path: {}",
        mu_lib_search_path
    );

    // Set library
    println!("cargo:rustc-link-lib=mu_std");
    eprintln!("[mu_lib build.rs] Library to link: mu_std");

    /* NOTE: Activate only when generating new bindings.
     * We primarily provide bindings,
     * so there's no need to generate bindings on every build.
     * However, if you want to generate new bindings, you can enable this code.
     * You need to provide MU_RB_HPP_PATH when you enable this code.
     */
    // let mu_rb_hpp_path = env::var("MU_RB_HPP_PATH")
    //     .unwrap_or("/usr/local/mu_library/mu/include/mu/mu_rb.hpp".to_string());
    // println!("cargo:rerun-if-changed={}", mu_rb_hpp_path);

    // let bindings = bindgen::Builder::default()
    //     .enable_cxx_namespaces()
    //     .header(mu_rb_hpp_path)
    //     .use_core()
    //     .clang_arg(format!("-I{}/picolibc-rv/include", llvm_path)) // stdint.h
    //     .clang_arg(format!("-I{}/libcxx-rv/include/c++/v1", llvm_path)) // cstdint
    //     .clang_arg(format!("-I{}/include", mu_lib_path))
    //     .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
    //     .generate()
    //     .expect("Unable to generate bindings");
    // bindings
    //     .write_to_file("src/bindings.rs")
    //     .expect("Couldn't write bindings!");

    // Skip cc compilation for docs.rs builds
    // if env::var("DOCS_RS").is_ok() {
    //     println!("cargo:warning=Skipping cc compilation for docs.rs build");
    //     return;
    // }

    let startup_path = format!("{}/script/mu_startup.s", mu_lib_path);
    let clang_path = format!("{}/bin/clang", llvm_path);
    println!("cargo:rerun-if-changed={}", startup_path);
    cc::Build::new()
        .file(startup_path)
        .compiler(clang_path)
        .target("riscv64-unknown-none-elf")
        .flag("-c")
        .flag("-march=rv64imfdxmetis")
        // .flag("-fno-pic")
        // .flag("-fno-plt")
        .flag("-fno-pie")
        .flag("-Wno-unused-command-line-argument")
        .compile("startup");
}