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use session::config;
use middle::lang_items;
use rustc_data_structures::fx::FxHashSet;
use rustc_target::spec::PanicStrategy;
use syntax::ast;
use syntax::symbol::Symbol;
use syntax_pos::Span;
use hir::def_id::DefId;
use hir::intravisit::{Visitor, NestedVisitorMap};
use hir::intravisit;
use hir;
use ty::TyCtxt;
macro_rules! weak_lang_items {
($($name:ident, $item:ident, $sym:ident;)*) => (
struct Context<'a, 'tcx: 'a> {
tcx: TyCtxt<'a, 'tcx, 'tcx>,
items: &'a mut lang_items::LanguageItems,
}
pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
items: &mut lang_items::LanguageItems) {
if items.eh_personality().is_none() {
items.missing.push(lang_items::EhPersonalityLangItem);
}
if tcx.sess.target.target.options.custom_unwind_resume &
items.eh_unwind_resume().is_none() {
items.missing.push(lang_items::EhUnwindResumeLangItem);
}
{
let mut cx = Context { tcx, items };
tcx.hir.krate().visit_all_item_likes(&mut cx.as_deep_visitor());
}
verify(tcx, items);
}
pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol> {
lang_items::extract(attrs).and_then(|(name, _)| {
$(if name == stringify!($name) {
Some(Symbol::intern(stringify!($sym)))
} else)* {
None
}
})
}
pub fn whitelisted(tcx: TyCtxt, lang_item: lang_items::LangItem) -> bool {
if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
return lang_item == lang_items::EhPersonalityLangItem ||
lang_item == lang_items::EhUnwindResumeLangItem
}
false
}
fn verify<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
items: &lang_items::LanguageItems) {
let needs_check = tcx.sess.crate_types.borrow().iter().any(|kind| {
match *kind {
config::CrateType::Dylib |
config::CrateType::ProcMacro |
config::CrateType::Cdylib |
config::CrateType::Executable |
config::CrateType::Staticlib => true,
config::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);
}
}
$(
if missing.contains(&lang_items::$item) &&
!whitelisted(tcx, lang_items::$item) &&
items.$name().is_none() {
if lang_items::$item == lang_items::PanicImplLangItem {
tcx.sess.err(&format!("`#[panic_handler]` function required, \
but not found"));
} else if lang_items::$item == lang_items::OomLangItem {
tcx.sess.err(&format!("`#[alloc_error_handler]` function required, \
but not found"));
} else {
tcx.sess.err(&format!("language item required, but not found: `{}`",
stringify!($name)));
}
}
)*
}
impl<'a, 'tcx> Context<'a, 'tcx> {
fn register(&mut self, name: &str, span: Span) {
$(if name == stringify!($name) {
if self.items.$name().is_none() {
self.items.missing.push(lang_items::$item);
}
} else)* {
span_err!(self.tcx.sess, span, E0264,
"unknown external lang item: `{}`",
name);
}
}
}
impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> {
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'v> {
NestedVisitorMap::None
}
fn visit_foreign_item(&mut self, i: &hir::ForeignItem) {
if let Some((lang_item, _)) = lang_items::extract(&i.attrs) {
self.register(&lang_item.as_str(), i.span);
}
intravisit::walk_foreign_item(self, i)
}
}
impl<'a, 'tcx, 'gcx> TyCtxt<'a, 'tcx, 'gcx> {
pub fn is_weak_lang_item(&self, item_def_id: DefId) -> bool {
let lang_items = self.lang_items();
let did = Some(item_def_id);
$(lang_items.$name() == did)||+
}
}
) }
weak_lang_items! {
panic_impl, PanicImplLangItem, rust_begin_unwind;
eh_personality, EhPersonalityLangItem, rust_eh_personality;
eh_unwind_resume, EhUnwindResumeLangItem, rust_eh_unwind_resume;
oom, OomLangItem, rust_oom;
}