108 lines
3.8 KiB
Rust
108 lines
3.8 KiB
Rust
//! Validity checking for weak lang items
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use rustc_ast::Attribute;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_errors::struct_span_err;
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use rustc_hir as hir;
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use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
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use rustc_hir::lang_items::{self, LangItem};
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use rustc_hir::weak_lang_items::WEAK_ITEMS_REFS;
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use rustc_middle::middle::lang_items::required;
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use rustc_middle::ty::TyCtxt;
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use rustc_session::config::CrateType;
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use rustc_span::symbol::Symbol;
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use rustc_span::Span;
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struct Context<'a, 'tcx> {
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tcx: TyCtxt<'tcx>,
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items: &'a mut lang_items::LanguageItems,
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}
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/// Checks the crate for usage of weak lang items, returning a vector of all the
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/// language items required by this crate, but not defined yet.
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pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>, items: &mut lang_items::LanguageItems) {
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// These are never called by user code, they're generated by the compiler.
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// They will never implicitly be added to the `missing` array unless we do
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// so here.
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if items.eh_personality().is_none() {
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items.missing.push(LangItem::EhPersonality);
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}
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if tcx.sess.target.is_like_emscripten && items.eh_catch_typeinfo().is_none() {
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items.missing.push(LangItem::EhCatchTypeinfo);
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}
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{
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let mut cx = Context { tcx, items };
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tcx.hir().visit_all_item_likes(&mut cx.as_deep_visitor());
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}
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verify(tcx, items);
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}
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fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) {
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// We only need to check for the presence of weak lang items if we're
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// emitting something that's not an rlib.
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let needs_check = tcx.sess.crate_types().iter().any(|kind| match *kind {
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CrateType::Dylib
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| CrateType::ProcMacro
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| CrateType::Cdylib
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| CrateType::Executable
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| CrateType::Staticlib => true,
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CrateType::Rlib => false,
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});
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if !needs_check {
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return;
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}
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let mut missing = FxHashSet::default();
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for &cnum in tcx.crates(()).iter() {
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for &item in tcx.missing_lang_items(cnum).iter() {
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missing.insert(item);
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}
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}
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for (name, item) in WEAK_ITEMS_REFS.clone().into_sorted_vector().into_iter() {
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if missing.contains(&item) && required(tcx, item) && items.require(item).is_err() {
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if item == LangItem::PanicImpl {
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tcx.sess.err("`#[panic_handler]` function required, but not found");
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} else if item == LangItem::Oom {
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if !tcx.features().default_alloc_error_handler {
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tcx.sess.err("`#[alloc_error_handler]` function required, but not found");
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tcx.sess.note_without_error("Use `#![feature(default_alloc_error_handler)]` for a default error handler");
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}
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} else {
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tcx.sess.err(&format!("language item required, but not found: `{}`", name));
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}
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}
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}
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}
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impl<'a, 'tcx> Context<'a, 'tcx> {
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fn register(&mut self, name: Symbol, span: Span) {
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if let Some(&item) = WEAK_ITEMS_REFS.get(&name) {
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if self.items.require(item).is_err() {
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self.items.missing.push(item);
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}
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} else {
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struct_span_err!(self.tcx.sess, span, E0264, "unknown external lang item: `{}`", name)
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.emit();
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}
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}
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}
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impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
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type Map = intravisit::ErasedMap<'v>;
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fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
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NestedVisitorMap::None
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}
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fn visit_foreign_item(&mut self, i: &hir::ForeignItem<'_>) {
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let check_name = |attr: &Attribute, sym| attr.has_name(sym);
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let attrs = self.tcx.hir().attrs(i.hir_id());
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if let Some((lang_item, _)) = lang_items::extract(check_name, attrs) {
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self.register(lang_item, i.span);
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}
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intravisit::walk_foreign_item(self, i)
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}
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}
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