1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // Detecting language items.
13 // Language items are items that represent concepts intrinsic to the language
14 // itself. Examples are:
16 // * Traits that specify "kinds"; e.g. "Sync", "Send".
18 // * Traits that represent operators; e.g. "Add", "Sub", "Index".
20 // * Functions called by the compiler itself.
22 pub use self::LangItem::*;
24 use hir::map as hir_map;
26 use hir::def_id::DefId;
28 use middle::weak_lang_items;
29 use util::nodemap::FxHashMap;
32 use syntax::symbol::Symbol;
33 use hir::itemlikevisit::ItemLikeVisitor;
36 // The actual lang items defined come at the end of this file in one handy table.
37 // So you probably just want to nip down to the end.
38 macro_rules! language_item_table {
40 $( $variant:ident, $name:expr, $method:ident; )*
45 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
51 pub struct LanguageItems {
52 pub items: Vec<Option<DefId>>,
53 pub missing: Vec<LangItem>,
57 pub fn new() -> LanguageItems {
58 fn foo(_: LangItem) -> Option<DefId> { None }
61 items: vec![$(foo($variant)),*],
66 pub fn items(&self) -> &[Option<DefId>] {
70 pub fn item_name(index: usize) -> &'static str {
71 let item: Option<LangItem> = LangItem::from_u32(index as u32);
73 $( Some($variant) => $name, )*
78 pub fn require(&self, it: LangItem) -> Result<DefId, String> {
79 match self.items[it as usize] {
82 Err(format!("requires `{}` lang_item",
83 LanguageItems::item_name(it as usize)))
88 pub fn require_owned_box(&self) -> Result<DefId, String> {
89 self.require(OwnedBoxLangItem)
92 pub fn fn_trait_kind(&self, id: DefId) -> Option<ty::ClosureKind> {
94 (self.fn_trait(), ty::ClosureKind::Fn),
95 (self.fn_mut_trait(), ty::ClosureKind::FnMut),
96 (self.fn_once_trait(), ty::ClosureKind::FnOnce),
99 for &(opt_def_id, kind) in &def_id_kinds {
100 if Some(id) == opt_def_id {
110 pub fn $method(&self) -> Option<DefId> {
111 self.items[$variant as usize]
116 struct LanguageItemCollector<'a, 'tcx: 'a> {
117 items: LanguageItems,
119 hir_map: &'a hir_map::Map<'tcx>,
121 session: &'a Session,
123 item_refs: FxHashMap<&'static str, usize>,
126 impl<'a, 'v, 'tcx> ItemLikeVisitor<'v> for LanguageItemCollector<'a, 'tcx> {
127 fn visit_item(&mut self, item: &hir::Item) {
128 if let Some(value) = extract(&item.attrs) {
129 let item_index = self.item_refs.get(&*value.as_str()).cloned();
131 if let Some(item_index) = item_index {
132 self.collect_item(item_index, self.hir_map.local_def_id(item.id))
134 let span = self.hir_map.span(item.id);
135 span_err!(self.session, span, E0522,
136 "definition of an unknown language item: `{}`.",
142 fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem) {
143 // at present, lang items are always items, not trait items
146 fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem) {
147 // at present, lang items are always items, not impl items
151 impl<'a, 'tcx> LanguageItemCollector<'a, 'tcx> {
152 pub fn new(session: &'a Session, hir_map: &'a hir_map::Map<'tcx>)
153 -> LanguageItemCollector<'a, 'tcx> {
154 let mut item_refs = FxHashMap();
156 $( item_refs.insert($name, $variant as usize); )*
158 LanguageItemCollector {
161 items: LanguageItems::new(),
166 pub fn collect_item(&mut self, item_index: usize,
167 item_def_id: DefId) {
168 // Check for duplicates.
169 match self.items.items[item_index] {
170 Some(original_def_id) if original_def_id != item_def_id => {
171 let cstore = &self.session.cstore;
172 let name = LanguageItems::item_name(item_index);
173 let mut err = match self.hir_map.span_if_local(item_def_id) {
174 Some(span) => struct_span_err!(
178 "duplicate lang item found: `{}`.",
180 None => self.session.struct_err(&format!(
181 "duplicate lang item in crate `{}`: `{}`.",
182 cstore.crate_name(item_def_id.krate),
185 if let Some(span) = self.hir_map.span_if_local(original_def_id) {
186 span_note!(&mut err, span,
187 "first defined here.");
189 err.note(&format!("first defined in crate `{}`.",
190 cstore.crate_name(original_def_id.krate)));
200 self.items.items[item_index] = Some(item_def_id);
203 pub fn collect_local_language_items(&mut self, krate: &hir::Crate) {
204 krate.visit_all_item_likes(self);
207 pub fn collect_external_language_items(&mut self) {
208 let cstore = &self.session.cstore;
210 for cnum in cstore.crates() {
211 for (index, item_index) in cstore.lang_items(cnum) {
212 let def_id = DefId { krate: cnum, index: index };
213 self.collect_item(item_index, def_id);
218 pub fn collect(&mut self, krate: &hir::Crate) {
219 self.collect_external_language_items();
220 self.collect_local_language_items(krate);
224 pub fn extract(attrs: &[ast::Attribute]) -> Option<Symbol> {
225 for attribute in attrs {
226 if attribute.check_name("lang") {
227 if let Some(value) = attribute.value_str() {
236 pub fn collect_language_items(session: &Session,
239 let krate: &hir::Crate = map.krate();
240 let mut collector = LanguageItemCollector::new(session, map);
241 collector.collect(krate);
242 let LanguageItemCollector { mut items, .. } = collector;
243 weak_lang_items::check_crate(krate, session, &mut items);
251 language_item_table! {
252 // Variant name, Name, Method name;
253 CharImplItem, "char", char_impl;
254 StrImplItem, "str", str_impl;
255 SliceImplItem, "slice", slice_impl;
256 ConstPtrImplItem, "const_ptr", const_ptr_impl;
257 MutPtrImplItem, "mut_ptr", mut_ptr_impl;
258 I8ImplItem, "i8", i8_impl;
259 I16ImplItem, "i16", i16_impl;
260 I32ImplItem, "i32", i32_impl;
261 I64ImplItem, "i64", i64_impl;
262 I128ImplItem, "i128", i128_impl;
263 IsizeImplItem, "isize", isize_impl;
264 U8ImplItem, "u8", u8_impl;
265 U16ImplItem, "u16", u16_impl;
266 U32ImplItem, "u32", u32_impl;
267 U64ImplItem, "u64", u64_impl;
268 U128ImplItem, "u128", u128_impl;
269 UsizeImplItem, "usize", usize_impl;
270 F32ImplItem, "f32", f32_impl;
271 F64ImplItem, "f64", f64_impl;
273 SendTraitLangItem, "send", send_trait;
274 SizedTraitLangItem, "sized", sized_trait;
275 UnsizeTraitLangItem, "unsize", unsize_trait;
276 CopyTraitLangItem, "copy", copy_trait;
277 CloneTraitLangItem, "clone", clone_trait;
278 SyncTraitLangItem, "sync", sync_trait;
279 FreezeTraitLangItem, "freeze", freeze_trait;
281 DropTraitLangItem, "drop", drop_trait;
283 CoerceUnsizedTraitLangItem, "coerce_unsized", coerce_unsized_trait;
285 AddTraitLangItem, "add", add_trait;
286 SubTraitLangItem, "sub", sub_trait;
287 MulTraitLangItem, "mul", mul_trait;
288 DivTraitLangItem, "div", div_trait;
289 RemTraitLangItem, "rem", rem_trait;
290 NegTraitLangItem, "neg", neg_trait;
291 NotTraitLangItem, "not", not_trait;
292 BitXorTraitLangItem, "bitxor", bitxor_trait;
293 BitAndTraitLangItem, "bitand", bitand_trait;
294 BitOrTraitLangItem, "bitor", bitor_trait;
295 ShlTraitLangItem, "shl", shl_trait;
296 ShrTraitLangItem, "shr", shr_trait;
297 AddAssignTraitLangItem, "add_assign", add_assign_trait;
298 SubAssignTraitLangItem, "sub_assign", sub_assign_trait;
299 MulAssignTraitLangItem, "mul_assign", mul_assign_trait;
300 DivAssignTraitLangItem, "div_assign", div_assign_trait;
301 RemAssignTraitLangItem, "rem_assign", rem_assign_trait;
302 BitXorAssignTraitLangItem, "bitxor_assign", bitxor_assign_trait;
303 BitAndAssignTraitLangItem, "bitand_assign", bitand_assign_trait;
304 BitOrAssignTraitLangItem, "bitor_assign", bitor_assign_trait;
305 ShlAssignTraitLangItem, "shl_assign", shl_assign_trait;
306 ShrAssignTraitLangItem, "shr_assign", shr_assign_trait;
307 IndexTraitLangItem, "index", index_trait;
308 IndexMutTraitLangItem, "index_mut", index_mut_trait;
310 UnsafeCellTypeLangItem, "unsafe_cell", unsafe_cell_type;
312 DerefTraitLangItem, "deref", deref_trait;
313 DerefMutTraitLangItem, "deref_mut", deref_mut_trait;
315 FnTraitLangItem, "fn", fn_trait;
316 FnMutTraitLangItem, "fn_mut", fn_mut_trait;
317 FnOnceTraitLangItem, "fn_once", fn_once_trait;
319 GeneratorStateLangItem, "generator_state", gen_state;
320 GeneratorTraitLangItem, "generator", gen_trait;
322 EqTraitLangItem, "eq", eq_trait;
323 OrdTraitLangItem, "ord", ord_trait;
325 StrEqFnLangItem, "str_eq", str_eq_fn;
327 // A number of panic-related lang items. The `panic` item corresponds to
328 // divide-by-zero and various panic cases with `match`. The
329 // `panic_bounds_check` item is for indexing arrays.
331 // The `begin_unwind` lang item has a predefined symbol name and is sort of
332 // a "weak lang item" in the sense that a crate is not required to have it
333 // defined to use it, but a final product is required to define it
334 // somewhere. Additionally, there are restrictions on crates that use a weak
335 // lang item, but do not have it defined.
336 PanicFnLangItem, "panic", panic_fn;
337 PanicBoundsCheckFnLangItem, "panic_bounds_check", panic_bounds_check_fn;
338 PanicFmtLangItem, "panic_fmt", panic_fmt;
340 ExchangeMallocFnLangItem, "exchange_malloc", exchange_malloc_fn;
341 BoxFreeFnLangItem, "box_free", box_free_fn;
342 DropInPlaceFnLangItem, "drop_in_place", drop_in_place_fn;
344 StartFnLangItem, "start", start_fn;
346 EhPersonalityLangItem, "eh_personality", eh_personality;
347 EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume;
348 MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter;
350 OwnedBoxLangItem, "owned_box", owned_box;
352 PhantomDataItem, "phantom_data", phantom_data;
355 CovariantTypeItem, "covariant_type", covariant_type;
356 ContravariantTypeItem, "contravariant_type", contravariant_type;
357 InvariantTypeItem, "invariant_type", invariant_type;
358 CovariantLifetimeItem, "covariant_lifetime", covariant_lifetime;
359 ContravariantLifetimeItem, "contravariant_lifetime", contravariant_lifetime;
360 InvariantLifetimeItem, "invariant_lifetime", invariant_lifetime;
362 NonZeroItem, "non_zero", non_zero;
364 DebugTraitLangItem, "debug_trait", debug_trait;
367 impl<'a, 'tcx, 'gcx> ty::TyCtxt<'a, 'tcx, 'gcx> {
368 pub fn require_lang_item(&self, lang_item: LangItem) -> DefId {
369 self.lang_items.require(lang_item).unwrap_or_else(|msg| {
370 self.sess.fatal(&msg)