text-generation-inference/backends/llamacpp/build.rs

use bindgen::callbacks::{ItemInfo, ParseCallbacks};
use std::collections::HashMap;
use std::env;
use std::path::PathBuf;

fn inject_transient_dependencies(lib_search_path: Option<&str>, lib_target_hardware: &str) {
    let hardware_targets = HashMap::from([("cpu", None), ("cuda", Some(vec!["cuda"]))]);

    if let Some(lib_search_path) = lib_search_path {
        lib_search_path.split(":").for_each(|path| {
            println!("cargo:rustc-link-search=dependency={path}");
        });
    }

    if let Some(hardware_transient_deps) = hardware_targets.get(lib_target_hardware) {
        if let Some(additional_transient_deps) = hardware_transient_deps {
            additional_transient_deps.iter().for_each(|dep| {
                println!("cargo:rustc-link-lib={dep}");
            });
        }
    }
}

#[derive(Debug)]
struct PrefixStripper;

impl ParseCallbacks for PrefixStripper {
    fn generated_name_override(&self, item_info: ItemInfo<'_>) -> Option<String> {
        item_info.name.strip_prefix("llama_").map(str::to_string)
    }
}

fn main() {
    let pkg_cuda = option_env!("TGI_LLAMA_PKG_CUDA");
    let lib_search_path = option_env!("TGI_LLAMA_LD_LIBRARY_PATH");
    let lib_target_hardware = option_env!("TGI_LLAMA_HARDWARE_TARGET").unwrap_or("cpu");

    let bindings = bindgen::Builder::default()
        .header("src/wrapper.h")
        .prepend_enum_name(false)
        .parse_callbacks(Box::new(PrefixStripper))
        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
        .generate()
        .expect("Unable to generate bindings");

    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
    bindings
        .write_to_file(out_path.join("llamacpp.rs"))
        .expect("Couldn't write bindings!");

    if let Some(pkg_cuda) = pkg_cuda {
        pkg_config::Config::new().probe(pkg_cuda).unwrap();
    }
    pkg_config::Config::new().probe("llama").unwrap();

    inject_transient_dependencies(lib_search_path, lib_target_hardware);
}