rustc_incremental/persist/

work_product.rs

//! Function for saving intermediate [work products].
//!
//! [work products]: WorkProduct

use std::path::Path;

use rustc_data_structures::unord::UnordMap;
use rustc_fs_util::link_or_copy;
use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
use rustc_session::{IncrCompSession, Session};
use tracing::debug;

use crate::diagnostics;
use crate::persist::fs::*;

/// Copies a CGU work product to the incremental compilation directory, so next compilation can
/// find and reuse it.
///
/// Panics when incr comp is disabled.
pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
    sess: &Session,
    incr_comp_session: &IncrCompSession,
    cgu_name: &str,
    files: &[(&'static str, &Path)],
) -> (WorkProductId, WorkProduct) {
    debug!(?cgu_name, ?files);
    assert!(sess.opts.incremental.is_some());

    let mut saved_files = UnordMap::default();
    for (ext, path) in files {
        let file_name = format!("{cgu_name}.{ext}");
        let path_in_incr_dir = in_incr_comp_dir_sess(incr_comp_session, &file_name);
        match link_or_copy(path, &path_in_incr_dir) {
            Ok(_) => {
                let _ = saved_files.insert(ext.to_string(), file_name);
            }
            Err(err) => {
                sess.dcx().emit_warn(diagnostics::CopyWorkProductToCache {
                    from: path,
                    to: &path_in_incr_dir,
                    err,
                });
            }
        }
    }

    let work_product = WorkProduct { cgu_name: cgu_name.to_string(), saved_files };
    debug!(?work_product);
    let work_product_id = WorkProductId::from_cgu_name(cgu_name);
    (work_product_id, work_product)
}