pub(crate) fn codegen(tcx: TyCtxt<'_>, module: &mut dyn Module) -> bool {
    let Some(kind) = allocator_kind_for_codegen(tcx) else { return false };
    codegen_inner(
        tcx,
        module,
        kind,
        tcx.alloc_error_handler_kind(()).unwrap(),
        tcx.sess.opts.unstable_opts.oom,
    );
    true
}
Returns whether an allocator shim was created
src/allocator.rs