1 //! Used by `rustc` when compiling a plugin crate.
4 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
5 use rustc::hir::itemlikevisit::ItemLikeVisitor;
6 use rustc::ty::query::Providers;
9 use syntax::symbol::sym;
12 struct RegistrarFinder {
13 registrars: Vec<(hir::HirId, Span)>,
16 impl<'v> ItemLikeVisitor<'v> for RegistrarFinder {
17 fn visit_item(&mut self, item: &hir::Item<'_>) {
18 if let hir::ItemKind::Fn(..) = item.kind {
19 if attr::contains_name(&item.attrs, sym::plugin_registrar) {
20 self.registrars.push((item.hir_id, item.span));
25 fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'_>) {}
27 fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'_>) {}
30 /// Finds the function marked with `#[plugin_registrar]`, if any.
31 pub fn find_plugin_registrar(tcx: TyCtxt<'_>) -> Option<DefId> {
32 tcx.plugin_registrar_fn(LOCAL_CRATE)
35 fn plugin_registrar_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> {
36 assert_eq!(cnum, LOCAL_CRATE);
38 let mut finder = RegistrarFinder { registrars: Vec::new() };
39 tcx.hir().krate().visit_all_item_likes(&mut finder);
41 match finder.registrars.len() {
44 let (hir_id, _) = finder.registrars.pop().unwrap();
45 Some(tcx.hir().local_def_id(hir_id))
48 let diagnostic = tcx.sess.diagnostic();
49 let mut e = diagnostic.struct_err("multiple plugin registration functions found");
50 for &(_, span) in &finder.registrars {
51 e.span_note(span, "one is here");
54 diagnostic.abort_if_errors();
60 pub fn provide(providers: &mut Providers<'_>) {
61 *providers = Providers { plugin_registrar_fn, ..*providers };