| //! Validity checking for weak lang items |
| |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_hir::lang_items::{self, LangItem}; |
| use rustc_hir::weak_lang_items::WEAK_LANG_ITEMS; |
| use rustc_middle::middle::lang_items::required; |
| use rustc_middle::ty::TyCtxt; |
| use rustc_session::config::CrateType; |
| |
| use crate::errors::{MissingLangItem, MissingPanicHandler, UnknownExternLangItem}; |
| |
| /// 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: TyCtxt<'_>, 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(LangItem::EhPersonality); |
| } |
| if tcx.sess.target.os == "emscripten" && items.eh_catch_typeinfo().is_none() { |
| items.missing.push(LangItem::EhCatchTypeinfo); |
| } |
| |
| let crate_items = tcx.hir_crate_items(()); |
| for id in crate_items.foreign_items() { |
| let attrs = tcx.hir().attrs(id.hir_id()); |
| if let Some((lang_item, _)) = lang_items::extract(attrs) { |
| if let Some(item) = LangItem::from_name(lang_item) |
| && item.is_weak() |
| { |
| if items.get(item).is_none() { |
| items.missing.push(item); |
| } |
| } else { |
| let span = tcx.def_span(id.owner_id); |
| tcx.sess.emit_err(UnknownExternLangItem { span, lang_item }); |
| } |
| } |
| } |
| |
| verify(tcx, items); |
| } |
| |
| fn verify(tcx: TyCtxt<'_>, 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.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 &item in WEAK_LANG_ITEMS.iter() { |
| if missing.contains(&item) && required(tcx, item) && items.get(item).is_none() { |
| if item == LangItem::PanicImpl { |
| tcx.sess.emit_err(MissingPanicHandler); |
| } else { |
| tcx.sess.emit_err(MissingLangItem { name: item.name() }); |
| } |
| } |
| } |
| } |