| //! Used by `rustc` when compiling a plugin crate. |
| |
| use syntax::attr; |
| use syntax::symbol::sym; |
| use syntax_pos::Span; |
| use rustc::hir::itemlikevisit::ItemLikeVisitor; |
| use rustc::hir; |
| use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE}; |
| use rustc::ty::TyCtxt; |
| use rustc::ty::query::Providers; |
| |
| struct RegistrarFinder { |
| registrars: Vec<(hir::HirId, Span)> , |
| } |
| |
| impl<'v> ItemLikeVisitor<'v> for RegistrarFinder { |
| fn visit_item(&mut self, item: &hir::Item) { |
| if let hir::ItemKind::Fn(..) = item.node { |
| if attr::contains_name(&item.attrs, sym::plugin_registrar) { |
| self.registrars.push((item.hir_id, item.span)); |
| } |
| } |
| } |
| |
| fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem) { |
| } |
| |
| fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem) { |
| } |
| } |
| |
| /// Finds the function marked with `#[plugin_registrar]`, if any. |
| pub fn find_plugin_registrar(tcx: TyCtxt<'_>) -> Option<DefId> { |
| tcx.plugin_registrar_fn(LOCAL_CRATE) |
| } |
| |
| fn plugin_registrar_fn(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> { |
| assert_eq!(cnum, LOCAL_CRATE); |
| |
| let mut finder = RegistrarFinder { registrars: Vec::new() }; |
| tcx.hir().krate().visit_all_item_likes(&mut finder); |
| |
| match finder.registrars.len() { |
| 0 => None, |
| 1 => { |
| let (hir_id, _) = finder.registrars.pop().unwrap(); |
| Some(tcx.hir().local_def_id(hir_id)) |
| }, |
| _ => { |
| let diagnostic = tcx.sess.diagnostic(); |
| let mut e = diagnostic.struct_err("multiple plugin registration functions found"); |
| for &(_, span) in &finder.registrars { |
| e.span_note(span, "one is here"); |
| } |
| e.emit(); |
| diagnostic.abort_if_errors(); |
| unreachable!(); |
| } |
| } |
| } |
| |
| |
| pub fn provide(providers: &mut Providers<'_>) { |
| *providers = Providers { |
| plugin_registrar_fn, |
| ..*providers |
| }; |
| } |