Method pipeline_for

src/build.rs:403–422

(manifest: &BuildManifest)

    /// Drop stdlib objects no kept object references (directly or transitively).
    /// Program/extra objects and any object defining an entry symbol are roots.
    fn prune_unreferenced_stdlib(
        units: Vec<BuiltUnit>,
        prunable: &std::collections::HashSet<String>,
        entry: Option<&str>,
    ) -> Vec<BuiltUnit> {
        let entry_roots = ["_start", "_kernel_start"];
        let is_root = |unit: &BuiltUnit| {
            !prunable.contains(&unit.name)
                || unit.assembled.global_symbol_names().any(|symbol| {
                    entry_roots.contains(&symbol) || entry.is_some_and(|entry| entry == symbol)
                })
        };
        let mut kept: Vec<bool> = units.iter().map(is_root).collect();
        let mut needed: std::collections::HashSet<String> = units
            .iter()
            .zip(&kept)
            .filter(|(_, keep)| **keep)
            .flat_map(|(unit, _)| unit.assembled.undefined_symbol_names())
            .map(str::to_owned)
            .collect();
        loop {
            let mut changed = false;