1 //! Used by `rustc` when compiling a plugin crate.
4 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
5 use rustc_hir::itemlikevisit::ItemLikeVisitor;
6 use rustc_middle::ty::query::Providers;
7 use rustc_middle::ty::TyCtxt;
8 use rustc_span::symbol::sym;
11 struct RegistrarFinder<'tcx> {
13 registrars: Vec<(LocalDefId, Span)>,
16 impl<'v, 'tcx> ItemLikeVisitor<'v> for RegistrarFinder<'tcx> {
17 fn visit_item(&mut self, item: &hir::Item<'_>) {
18 if let hir::ItemKind::Fn(..) = item.kind {
19 if self.tcx.sess.contains_name(&item.attrs, sym::plugin_registrar) {
20 self.registrars.push((item.def_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<'_>) {}
29 fn visit_foreign_item(&mut self, _foreign_item: &hir::ForeignItem<'_>) {}
32 /// Finds the function marked with `#[plugin_registrar]`, if any.
33 pub fn find_plugin_registrar(tcx: TyCtxt<'_>) -> Option<DefId> {
34 tcx.plugin_registrar_fn(LOCAL_CRATE)
37 fn plugin_registrar_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> {
38 assert_eq!(cnum, LOCAL_CRATE);
40 let mut finder = RegistrarFinder { tcx, registrars: Vec::new() };
41 tcx.hir().krate().visit_all_item_likes(&mut finder);
43 match finder.registrars.len() {
46 let (def_id, _) = finder.registrars.pop().unwrap();
47 Some(def_id.to_def_id())
50 let diagnostic = tcx.sess.diagnostic();
51 let mut e = diagnostic.struct_err("multiple plugin registration functions found");
52 for &(_, span) in &finder.registrars {
53 e.span_note(span, "one is here");
56 diagnostic.abort_if_errors();
62 pub fn provide(providers: &mut Providers) {
63 *providers = Providers { plugin_registrar_fn, ..*providers };