88 lines
3 KiB
Rust
88 lines
3 KiB
Rust
//! Validity checking for weak lang items
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use rustc_ast as ast;
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use rustc_ast::visit;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_hir::lang_items::{self, LangItem};
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use rustc_hir::weak_lang_items::WEAK_LANG_ITEMS;
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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 crate::errors::{
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MissingLangItem, MissingPanicHandler, PanicUnwindWithoutStd, UnknownExternLangItem,
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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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/// lang items required by this crate, but not defined yet.
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pub fn check_crate(tcx: TyCtxt<'_>, items: &mut lang_items::LanguageItems, krate: &ast::Crate) {
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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.os == "emscripten" && items.eh_catch_typeinfo().is_none() {
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items.missing.push(LangItem::EhCatchTypeinfo);
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}
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visit::Visitor::visit_crate(&mut WeakLangItemVisitor { tcx, items }, krate);
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verify(tcx, items);
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}
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struct WeakLangItemVisitor<'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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impl<'ast> visit::Visitor<'ast> for WeakLangItemVisitor<'_, '_> {
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fn visit_foreign_item(&mut self, i: &'ast ast::ForeignItem) {
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if let Some((lang_item, _)) = lang_items::extract(&i.attrs) {
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if let Some(item) = LangItem::from_name(lang_item)
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&& item.is_weak()
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{
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if self.items.get(item).is_none() {
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self.items.missing.push(item);
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}
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} else {
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self.tcx.dcx().emit_err(UnknownExternLangItem { span: i.span, lang_item });
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}
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}
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}
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}
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fn verify(tcx: TyCtxt<'_>, 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.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 &item in WEAK_LANG_ITEMS.iter() {
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if missing.contains(&item) && required(tcx, item) && items.get(item).is_none() {
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if item == LangItem::PanicImpl {
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tcx.dcx().emit_err(MissingPanicHandler);
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} else if item == LangItem::EhPersonality {
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tcx.dcx().emit_err(PanicUnwindWithoutStd);
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} else {
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tcx.dcx().emit_err(MissingLangItem { name: item.name() });
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}
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}
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}
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}
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