// Copyright 2012 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. // Detecting language items. // // Language items are items that represent concepts intrinsic to the language // itself. Examples are: // // * Traits that specify "kinds"; e.g. "Sync", "Send". // // * Traits that represent operators; e.g. "Add", "Sub", "Index". // // * Functions called by the compiler itself. pub use self::LangItem::*; use dep_graph::DepNode; use front::map as hir_map; use session::Session; use middle::cstore::CrateStore; use middle::def_id::DefId; use middle::ty; use middle::weak_lang_items; use util::nodemap::FnvHashMap; use syntax::ast; use syntax::attr::AttrMetaMethods; use syntax::parse::token::InternedString; use rustc_front::intravisit::Visitor; use rustc_front::hir; // The actual lang items defined come at the end of this file in one handy table. // So you probably just want to nip down to the end. macro_rules! lets_do_this { ( $( $variant:ident, $name:expr, $method:ident; )* ) => { enum_from_u32! { #[derive(Copy, Clone, PartialEq, Eq, Hash)] pub enum LangItem { $($variant,)* } } pub struct LanguageItems { pub items: Vec>, pub missing: Vec, } impl LanguageItems { pub fn new() -> LanguageItems { fn foo(_: LangItem) -> Option { None } LanguageItems { items: vec!($(foo($variant)),*), missing: Vec::new(), } } pub fn items(&self) -> &[Option] { &*self.items } pub fn item_name(index: usize) -> &'static str { let item: Option = LangItem::from_u32(index as u32); match item { $( Some($variant) => $name, )* None => "???" } } pub fn require(&self, it: LangItem) -> Result { match self.items[it as usize] { Some(id) => Ok(id), None => { Err(format!("requires `{}` lang_item", LanguageItems::item_name(it as usize))) } } } pub fn require_owned_box(&self) -> Result { self.require(OwnedBoxLangItem) } pub fn from_builtin_kind(&self, bound: ty::BuiltinBound) -> Result { match bound { ty::BoundSend => self.require(SendTraitLangItem), ty::BoundSized => self.require(SizedTraitLangItem), ty::BoundCopy => self.require(CopyTraitLangItem), ty::BoundSync => self.require(SyncTraitLangItem), } } pub fn to_builtin_kind(&self, id: DefId) -> Option { if Some(id) == self.send_trait() { Some(ty::BoundSend) } else if Some(id) == self.sized_trait() { Some(ty::BoundSized) } else if Some(id) == self.copy_trait() { Some(ty::BoundCopy) } else if Some(id) == self.sync_trait() { Some(ty::BoundSync) } else { None } } pub fn fn_trait_kind(&self, id: DefId) -> Option { let def_id_kinds = [ (self.fn_trait(), ty::ClosureKind::Fn), (self.fn_mut_trait(), ty::ClosureKind::FnMut), (self.fn_once_trait(), ty::ClosureKind::FnOnce), ]; for &(opt_def_id, kind) in &def_id_kinds { if Some(id) == opt_def_id { return Some(kind); } } None } $( #[allow(dead_code)] pub fn $method(&self) -> Option { self.items[$variant as usize] } )* } struct LanguageItemCollector<'a, 'tcx: 'a> { items: LanguageItems, ast_map: &'a hir_map::Map<'tcx>, session: &'a Session, item_refs: FnvHashMap<&'static str, usize>, } impl<'a, 'v, 'tcx> Visitor<'v> for LanguageItemCollector<'a, 'tcx> { fn visit_item(&mut self, item: &hir::Item) { if let Some(value) = extract(&item.attrs) { let item_index = self.item_refs.get(&value[..]).cloned(); if let Some(item_index) = item_index { self.collect_item(item_index, self.ast_map.local_def_id(item.id)) } } } } impl<'a, 'tcx> LanguageItemCollector<'a, 'tcx> { pub fn new(session: &'a Session, ast_map: &'a hir_map::Map<'tcx>) -> LanguageItemCollector<'a, 'tcx> { let mut item_refs = FnvHashMap(); $( item_refs.insert($name, $variant as usize); )* LanguageItemCollector { session: session, ast_map: ast_map, items: LanguageItems::new(), item_refs: item_refs, } } pub fn collect_item(&mut self, item_index: usize, item_def_id: DefId) { // Check for duplicates. match self.items.items[item_index] { Some(original_def_id) if original_def_id != item_def_id => { let cstore = &self.session.cstore; let span = self.ast_map.span_if_local(item_def_id) .expect("we should have found local duplicate earlier"); let mut err = struct_span_err!(self.session, span, E0152, "duplicate lang item found: `{}`.", LanguageItems::item_name(item_index)); if let Some(span) = self.ast_map.span_if_local(original_def_id) { span_note!(&mut err, span, "first defined here."); } else { err.note(&format!("first defined in crate `{}`.", cstore.crate_name(original_def_id.krate))); } err.emit(); } _ => { // OK. } } // Matched. self.items.items[item_index] = Some(item_def_id); } pub fn collect_local_language_items(&mut self, krate: &hir::Crate) { krate.visit_all_items(self); } pub fn collect_external_language_items(&mut self) { let cstore = &self.session.cstore; for cnum in cstore.crates() { for (index, item_index) in cstore.lang_items(cnum) { let def_id = DefId { krate: cnum, index: index }; self.collect_item(item_index, def_id); } } } pub fn collect(&mut self, krate: &hir::Crate) { self.collect_external_language_items(); self.collect_local_language_items(krate); } } pub fn extract(attrs: &[ast::Attribute]) -> Option { for attribute in attrs { match attribute.value_str() { Some(ref value) if attribute.check_name("lang") => { return Some(value.clone()); } _ => {} } } return None; } pub fn collect_language_items(session: &Session, map: &hir_map::Map) -> LanguageItems { let _task = map.dep_graph.in_task(DepNode::CollectLanguageItems); let krate: &hir::Crate = map.krate(); let mut collector = LanguageItemCollector::new(session, map); collector.collect(krate); let LanguageItemCollector { mut items, .. } = collector; weak_lang_items::check_crate(krate, session, &mut items); items } // End of the macro } } lets_do_this! { // Variant name, Name, Method name; CharImplItem, "char", char_impl; StrImplItem, "str", str_impl; SliceImplItem, "slice", slice_impl; ConstPtrImplItem, "const_ptr", const_ptr_impl; MutPtrImplItem, "mut_ptr", mut_ptr_impl; I8ImplItem, "i8", i8_impl; I16ImplItem, "i16", i16_impl; I32ImplItem, "i32", i32_impl; I64ImplItem, "i64", i64_impl; IsizeImplItem, "isize", isize_impl; U8ImplItem, "u8", u8_impl; U16ImplItem, "u16", u16_impl; U32ImplItem, "u32", u32_impl; U64ImplItem, "u64", u64_impl; UsizeImplItem, "usize", usize_impl; F32ImplItem, "f32", f32_impl; F64ImplItem, "f64", f64_impl; SendTraitLangItem, "send", send_trait; SizedTraitLangItem, "sized", sized_trait; UnsizeTraitLangItem, "unsize", unsize_trait; CopyTraitLangItem, "copy", copy_trait; SyncTraitLangItem, "sync", sync_trait; DropTraitLangItem, "drop", drop_trait; CoerceUnsizedTraitLangItem, "coerce_unsized", coerce_unsized_trait; AddTraitLangItem, "add", add_trait; SubTraitLangItem, "sub", sub_trait; MulTraitLangItem, "mul", mul_trait; DivTraitLangItem, "div", div_trait; RemTraitLangItem, "rem", rem_trait; NegTraitLangItem, "neg", neg_trait; NotTraitLangItem, "not", not_trait; BitXorTraitLangItem, "bitxor", bitxor_trait; BitAndTraitLangItem, "bitand", bitand_trait; BitOrTraitLangItem, "bitor", bitor_trait; ShlTraitLangItem, "shl", shl_trait; ShrTraitLangItem, "shr", shr_trait; AddAssignTraitLangItem, "add_assign", add_assign_trait; SubAssignTraitLangItem, "sub_assign", sub_assign_trait; MulAssignTraitLangItem, "mul_assign", mul_assign_trait; DivAssignTraitLangItem, "div_assign", div_assign_trait; RemAssignTraitLangItem, "rem_assign", rem_assign_trait; BitXorAssignTraitLangItem, "bitxor_assign", bitxor_assign_trait; BitAndAssignTraitLangItem, "bitand_assign", bitand_assign_trait; BitOrAssignTraitLangItem, "bitor_assign", bitor_assign_trait; ShlAssignTraitLangItem, "shl_assign", shl_assign_trait; ShrAssignTraitLangItem, "shr_assign", shr_assign_trait; IndexTraitLangItem, "index", index_trait; IndexMutTraitLangItem, "index_mut", index_mut_trait; UnsafeCellTypeLangItem, "unsafe_cell", unsafe_cell_type; DerefTraitLangItem, "deref", deref_trait; DerefMutTraitLangItem, "deref_mut", deref_mut_trait; FnTraitLangItem, "fn", fn_trait; FnMutTraitLangItem, "fn_mut", fn_mut_trait; FnOnceTraitLangItem, "fn_once", fn_once_trait; EqTraitLangItem, "eq", eq_trait; OrdTraitLangItem, "ord", ord_trait; StrEqFnLangItem, "str_eq", str_eq_fn; // A number of panic-related lang items. The `panic` item corresponds to // divide-by-zero and various panic cases with `match`. The // `panic_bounds_check` item is for indexing arrays. // // The `begin_unwind` lang item has a predefined symbol name and is sort of // a "weak lang item" in the sense that a crate is not required to have it // defined to use it, but a final product is required to define it // somewhere. Additionally, there are restrictions on crates that use a weak // lang item, but do not have it defined. PanicFnLangItem, "panic", panic_fn; PanicBoundsCheckFnLangItem, "panic_bounds_check", panic_bounds_check_fn; PanicFmtLangItem, "panic_fmt", panic_fmt; ExchangeMallocFnLangItem, "exchange_malloc", exchange_malloc_fn; ExchangeFreeFnLangItem, "exchange_free", exchange_free_fn; BoxFreeFnLangItem, "box_free", box_free_fn; StrDupUniqFnLangItem, "strdup_uniq", strdup_uniq_fn; StartFnLangItem, "start", start_fn; EhPersonalityLangItem, "eh_personality", eh_personality; EhPersonalityCatchLangItem, "eh_personality_catch", eh_personality_catch; EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume; MSVCTryFilterLangItem, "msvc_try_filter", msvc_try_filter; OwnedBoxLangItem, "owned_box", owned_box; PhantomDataItem, "phantom_data", phantom_data; // Deprecated: CovariantTypeItem, "covariant_type", covariant_type; ContravariantTypeItem, "contravariant_type", contravariant_type; InvariantTypeItem, "invariant_type", invariant_type; CovariantLifetimeItem, "covariant_lifetime", covariant_lifetime; ContravariantLifetimeItem, "contravariant_lifetime", contravariant_lifetime; InvariantLifetimeItem, "invariant_lifetime", invariant_lifetime; NoCopyItem, "no_copy_bound", no_copy_bound; NonZeroItem, "non_zero", non_zero; DebugTraitLangItem, "debug_trait", debug_trait; }