build.rs

//! This build script copies the `memory.x` file from the crate root into
//! a directory where the linker can always find it at build time.
//! For many projects this is optional, as the linker always searches the
//! project root directory -- wherever `Cargo.toml` is. However, if you
//! are using a workspace or have a more complicated build setup, this
//! build script becomes required. Additionally, by requesting that
//! Cargo re-run the build script whenever `memory.x` is changed,
//! updating `memory.x` ensures a rebuild of the application with the
//! new memory settings.

use std::env;
use std::fs::File;
use std::io::Write;
use std::path::PathBuf;

fn main() {
    build_data::set_GIT_BRANCH();
    build_data::set_GIT_COMMIT();
    build_data::set_SOURCE_TIMESTAMP();
    build_data::set_RUSTC_VERSION();
    build_data::no_debug_rebuilds();

    let mut memory_x = include_bytes!("memory.x").to_vec();
    if let Some(_feature) = env::var_os("CARGO_FEATURE_BLUE_PILL") {
        memory_x = include_bytes!("memory-blue_pill.x").to_vec();
    }
    if let Some(_feature) = env::var_os("CARGO_FEATURE_BLACK_PILL") {
        memory_x = include_bytes!("memory-black_pill.x").to_vec();
    }
    if let Some(_feature) = env::var_os("CARGO_FEATURE_NUCLEO_F411") {
        memory_x = include_bytes!("memory-nucleo_f411.x").to_vec();
    }

    // Put `memory.x` in our output directory and ensure it's
    // on the linker search path.
    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
    File::create(out.join("memory.x"))
        .unwrap()
        .write_all(&memory_x)
        .unwrap();
    println!("cargo:rustc-link-search={}", out.display());

    // By default, Cargo will re-run a build script whenever
    // any file in the project changes. By specifying `memory.x`
    // here, we ensure the build script is only re-run when
    // `memory.x` is changed.
    println!("cargo:rerun-if-changed=memory.x");
}