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_middle::ty::{Instance, TyCtxt};
   9 use rustc_span::symbol::{sym, Symbol};
  10
  11 const SYMBOL_NAME: Symbol = sym::rustc_symbol_name;
  12 const DEF_PATH: Symbol = sym::rustc_def_path;
  13
  14 pub fn report_symbol_names(tcx: TyCtxt<'_>) {
  15     // if the `rustc_attrs` feature is not enabled, then the
  16     // attributes we are interested in cannot be present anyway, so
  17     // skip the walk.
  18     if !tcx.features().rustc_attrs {
  19         return;
  20     }
  21
  22     tcx.dep_graph.with_ignore(|| {
  23         let mut visitor = SymbolNamesTest { tcx };
  24         tcx.hir().krate().visit_all_item_likes(&mut visitor);
  25     })
  26 }
  27
  28 struct SymbolNamesTest<'tcx> {
  29     tcx: TyCtxt<'tcx>,
  30 }
  31
  32 impl SymbolNamesTest<'tcx> {
  33     fn process_attrs(&mut self, hir_id: hir::HirId) {
  34         let tcx = self.tcx;
  35         let def_id = tcx.hir().local_def_id(hir_id);
  36         for attr in tcx.get_attrs(def_id.to_def_id()).iter() {
  37             if tcx.sess.check_name(attr, SYMBOL_NAME) {
  38                 // for now, can only use on monomorphic names
  39                 let instance = Instance::mono(tcx, def_id.to_def_id());
  40                 let mangled = tcx.symbol_name(instance);
  41                 tcx.sess.span_err(attr.span, &format!("symbol-name({})", mangled));
  42                 if let Ok(demangling) = rustc_demangle::try_demangle(mangled.name) {
  43                     tcx.sess.span_err(attr.span, &format!("demangling({})", demangling));
  44                     tcx.sess.span_err(attr.span, &format!("demangling-alt({:#})", demangling));
  45                 }
  46             } else if tcx.sess.check_name(attr, DEF_PATH) {
  47                 let path = tcx.def_path_str(def_id.to_def_id());
  48                 tcx.sess.span_err(attr.span, &format!("def-path({})", path));
  49             }
  50
  51             // (*) The formatting of `tag({})` is chosen so that tests can elect
  52             // to test the entirety of the string, if they choose, or else just
  53             // some subset.
  54         }
  55     }
  56 }
  57
  58 impl hir::itemlikevisit::ItemLikeVisitor<'tcx> for SymbolNamesTest<'tcx> {
  59     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
  60         self.process_attrs(item.hir_id);
  61     }
  62
  63     fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem<'tcx>) {
  64         self.process_attrs(trait_item.hir_id);
  65     }
  66
  67     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem<'tcx>) {
  68         self.process_attrs(impl_item.hir_id);
  69     }
  70 }