| //! Validity checking for weak lang items |
| |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_errors::struct_span_err; |
| use rustc_hir as hir; |
| use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; |
| use rustc_hir::lang_items; |
| use rustc_hir::lang_items::ITEM_REFS; |
| use rustc_hir::weak_lang_items::WEAK_ITEMS_REFS; |
| use rustc_middle::middle::lang_items::required; |
| use rustc_middle::ty::TyCtxt; |
| use rustc_session::config::CrateType; |
| use rustc_span::symbol::sym; |
| use rustc_span::symbol::Symbol; |
| use rustc_span::Span; |
| |
| struct Context<'a, 'tcx> { |
| tcx: TyCtxt<'tcx>, |
| items: &'a mut lang_items::LanguageItems, |
| } |
| |
| /// Checks the crate for usage of weak lang items, returning a vector of all the |
| /// language items required by this crate, but not defined yet. |
| pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>, items: &mut lang_items::LanguageItems) { |
| // These are never called by user code, they're generated by the compiler. |
| // They will never implicitly be added to the `missing` array unless we do |
| // so here. |
| if items.eh_personality().is_none() { |
| items.missing.push(lang_items::EhPersonalityLangItem); |
| } |
| |
| { |
| let mut cx = Context { tcx, items }; |
| tcx.hir().krate().visit_all_item_likes(&mut cx.as_deep_visitor()); |
| } |
| verify(tcx, items); |
| } |
| |
| fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) { |
| // We only need to check for the presence of weak lang items if we're |
| // emitting something that's not an rlib. |
| let needs_check = tcx.sess.crate_types().iter().any(|kind| match *kind { |
| CrateType::Dylib |
| | CrateType::ProcMacro |
| | CrateType::Cdylib |
| | CrateType::Executable |
| | CrateType::Staticlib => true, |
| CrateType::Rlib => false, |
| }); |
| if !needs_check { |
| return; |
| } |
| |
| let mut missing = FxHashSet::default(); |
| for &cnum in tcx.crates().iter() { |
| for &item in tcx.missing_lang_items(cnum).iter() { |
| missing.insert(item); |
| } |
| } |
| |
| for (name, &item) in WEAK_ITEMS_REFS.iter() { |
| if missing.contains(&item) && required(tcx, item) && items.require(item).is_err() { |
| if item == lang_items::PanicImplLangItem { |
| tcx.sess.err("`#[panic_handler]` function required, but not found"); |
| } else if item == lang_items::OomLangItem { |
| tcx.sess.err("`#[alloc_error_handler]` function required, but not found"); |
| } else { |
| tcx.sess.err(&format!("language item required, but not found: `{}`", name)); |
| } |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> Context<'a, 'tcx> { |
| fn register(&mut self, name: Symbol, span: Span, hir_id: hir::HirId) { |
| if let Some(&item) = WEAK_ITEMS_REFS.get(&name) { |
| if self.items.require(item).is_err() { |
| self.items.missing.push(item); |
| } |
| } else if name == sym::count_code_region { |
| // `core::intrinsics::code_count_region()` is (currently) the only `extern` lang item |
| // that is never actually linked. It is not a `weak_lang_item` that can be registered |
| // when used, and should be registered here instead. |
| if let Some((item_index, _)) = ITEM_REFS.get(&*name.as_str()).cloned() { |
| if self.items.items[item_index].is_none() { |
| let item_def_id = self.tcx.hir().local_def_id(hir_id).to_def_id(); |
| self.items.items[item_index] = Some(item_def_id); |
| } |
| } |
| } else { |
| struct_span_err!(self.tcx.sess, span, E0264, "unknown external lang item: `{}`", name) |
| .emit(); |
| } |
| } |
| } |
| |
| impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> { |
| type Map = intravisit::ErasedMap<'v>; |
| |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::None |
| } |
| |
| fn visit_foreign_item(&mut self, i: &hir::ForeignItem<'_>) { |
| if let Some((lang_item, _)) = hir::lang_items::extract(&i.attrs) { |
| self.register(lang_item, i.span, i.hir_id); |
| } |
| intravisit::walk_foreign_item(self, i) |
| } |
| } |