compiler/rustc_symbol_mangling/src/test.rs

   1 //! Walks the crate looking for items/impl-items/trait-items that have
   2 //! either a `rustc_symbol_name` or `rustc_def_path` attribute and
   3 //! generates an error giving, respectively, the symbol name or
   4 //! def-path. This is used for unit testing the code that generates
   5 //! paths etc in all kinds of annoying scenarios.
   6
   7 use rustc_hir as hir;
   8 use rustc_hir::def_id::LocalDefId;
   9 use rustc_middle::ty::print::with_no_trimmed_paths;
  10 use rustc_middle::ty::{subst::InternalSubsts, Instance, TyCtxt};
  11 use rustc_span::symbol::{sym, Symbol};
  12
  13 const SYMBOL_NAME: Symbol = sym::rustc_symbol_name;
  14 const DEF_PATH: Symbol = sym::rustc_def_path;
  15
  16 pub fn report_symbol_names(tcx: TyCtxt<'_>) {
  17     // if the `rustc_attrs` feature is not enabled, then the
  18     // attributes we are interested in cannot be present anyway, so
  19     // skip the walk.
  20     if !tcx.features().rustc_attrs {
  21         return;
  22     }
  23
  24     tcx.dep_graph.with_ignore(|| {
  25         let mut visitor = SymbolNamesTest { tcx };
  26         tcx.hir().krate().visit_all_item_likes(&mut visitor);
  27     })
  28 }
  29
  30 struct SymbolNamesTest<'tcx> {
  31     tcx: TyCtxt<'tcx>,
  32 }
  33
  34 impl SymbolNamesTest<'tcx> {
  35     fn process_attrs(&mut self, def_id: LocalDefId) {
  36         let tcx = self.tcx;
  37         for attr in tcx.get_attrs(def_id.to_def_id()).iter() {
  38             if tcx.sess.check_name(attr, SYMBOL_NAME) {
  39                 let def_id = def_id.to_def_id();
  40                 let instance = Instance::new(
  41                     def_id,
  42                     tcx.erase_regions(InternalSubsts::identity_for_item(tcx, def_id)),
  43                 );
  44                 let mangled = tcx.symbol_name(instance);
  45                 tcx.sess.span_err(attr.span, &format!("symbol-name({})", mangled));
  46                 if let Ok(demangling) = rustc_demangle::try_demangle(mangled.name) {
  47                     tcx.sess.span_err(attr.span, &format!("demangling({})", demangling));
  48                     tcx.sess.span_err(attr.span, &format!("demangling-alt({:#})", demangling));
  49                 }
  50             } else if tcx.sess.check_name(attr, DEF_PATH) {
  51                 let path = with_no_trimmed_paths(|| tcx.def_path_str(def_id.to_def_id()));
  52                 tcx.sess.span_err(attr.span, &format!("def-path({})", path));
  53             }
  54
  55             // (*) The formatting of `tag({})` is chosen so that tests can elect
  56             // to test the entirety of the string, if they choose, or else just
  57             // some subset.
  58         }
  59     }
  60 }
  61
  62 impl hir::itemlikevisit::ItemLikeVisitor<'tcx> for SymbolNamesTest<'tcx> {
  63     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
  64         self.process_attrs(item.def_id);
  65     }
  66
  67     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
  68         self.process_attrs(trait_item.def_id);
  69     }
  70
  71     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
  72         self.process_attrs(impl_item.def_id);
  73     }
  74
  75     fn visit_foreign_item(&mut self, foreign_item: &'tcx hir::ForeignItem<'tcx>) {
  76         self.process_attrs(foreign_item.def_id);
  77     }
  78 }