src/librustc_interface/proc_macro_decls.rs

   1 use rustc_hir as hir;
   2 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
   3 use rustc_hir::itemlikevisit::ItemLikeVisitor;
   4 use rustc_middle::ty::query::Providers;
   5 use rustc_middle::ty::TyCtxt;
   6 use rustc_span::symbol::sym;
   7
   8 pub fn find(tcx: TyCtxt<'_>) -> Option<DefId> {
   9     tcx.proc_macro_decls_static(LOCAL_CRATE)
  10 }
  11
  12 fn proc_macro_decls_static(tcx: TyCtxt<'_>, cnum: CrateNum) -> Option<DefId> {
  13     assert_eq!(cnum, LOCAL_CRATE);
  14
  15     let mut finder = Finder { tcx, decls: None };
  16     tcx.hir().krate().visit_all_item_likes(&mut finder);
  17
  18     finder.decls.map(|id| tcx.hir().local_def_id(id).to_def_id())
  19 }
  20
  21 struct Finder<'tcx> {
  22     tcx: TyCtxt<'tcx>,
  23     decls: Option<hir::HirId>,
  24 }
  25
  26 impl<'v> ItemLikeVisitor<'v> for Finder<'_> {
  27     fn visit_item(&mut self, item: &hir::Item<'_>) {
  28         if self.tcx.sess.contains_name(&item.attrs, sym::rustc_proc_macro_decls) {
  29             self.decls = Some(item.hir_id);
  30         }
  31     }
  32
  33     fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'_>) {}
  34
  35     fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'_>) {}
  36 }
  37
  38 pub(crate) fn provide(providers: &mut Providers) {
  39     *providers = Providers { proc_macro_decls_static, ..*providers };
  40 }