diff options
Diffstat (limited to 'src')
25 files changed, 687 insertions, 628 deletions
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs index 2e7e8fdd724..7d48280661a 100644 --- a/src/librustc/hir/mod.rs +++ b/src/librustc/hir/mod.rs @@ -2,7 +2,6 @@ //! //! [rustc guide]: https://rust-lang.github.io/rustc-guide/hir.html -pub mod check_attr; pub mod exports; pub mod map; diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs index 625d8a4670f..1a763e43d55 100644 --- a/src/librustc/ich/impls_hir.rs +++ b/src/librustc/ich/impls_hir.rs @@ -251,12 +251,6 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::def_id::DefIndex { } } -impl<'a> HashStable<StableHashingContext<'a>> for crate::middle::lang_items::LangItem { - fn hash_stable(&self, _: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { - ::std::hash::Hash::hash(self, hasher); - } -} - impl<'a> HashStable<StableHashingContext<'a>> for hir::TraitCandidate { fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) { hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| { diff --git a/src/librustc/macros.rs b/src/librustc/macros.rs index 2bda0c0bef0..88ddd96eec8 100644 --- a/src/librustc/macros.rs +++ b/src/librustc/macros.rs @@ -1,40 +1,3 @@ -macro_rules! enum_from_u32 { - ($(#[$attr:meta])* pub enum $name:ident { - $($variant:ident = $e:expr,)* - }) => { - $(#[$attr])* - pub enum $name { - $($variant = $e),* - } - - impl $name { - pub fn from_u32(u: u32) -> Option<$name> { - $(if u == $name::$variant as u32 { - return Some($name::$variant) - })* - None - } - } - }; - ($(#[$attr:meta])* pub enum $name:ident { - $($variant:ident,)* - }) => { - $(#[$attr])* - pub enum $name { - $($variant,)* - } - - impl $name { - pub fn from_u32(u: u32) -> Option<$name> { - $(if u == $name::$variant as u32 { - return Some($name::$variant) - })* - None - } - } - } -} - #[macro_export] macro_rules! bug { () => ( bug!("impossible case reached") ); diff --git a/src/librustc/middle/lang_items.rs b/src/librustc/middle/lang_items.rs index 9e33ee8da21..c8e284be6fc 100644 --- a/src/librustc/middle/lang_items.rs +++ b/src/librustc/middle/lang_items.rs @@ -9,401 +9,14 @@ pub use self::LangItem::*; -use crate::hir::check_attr::Target; -use crate::middle::cstore::ExternCrate; -use crate::middle::weak_lang_items; use crate::ty::{self, TyCtxt}; -use rustc_data_structures::fx::FxHashMap; -use rustc_errors::struct_span_err; -use rustc_hir as hir; use rustc_hir::def_id::DefId; -use rustc_hir::itemlikevisit::ItemLikeVisitor; -use rustc_macros::HashStable; -use rustc_span::symbol::{sym, Symbol}; use rustc_span::Span; -use syntax::ast; +use rustc_target::spec::PanicStrategy; -// 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! language_item_table { - ( - $( $variant:ident, $name:expr, $method:ident, $target:path; )* - ) => { - -enum_from_u32! { - /// A representation of all the valid language items in Rust. - #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)] - pub enum LangItem { - $($variant,)* - } -} - -impl LangItem { - /// Returns the `name` in `#[lang = "$name"]`. - /// For example, `LangItem::EqTraitLangItem`, - /// that is `#[lang = "eq"]` would result in `"eq"`. - fn name(self) -> &'static str { - match self { - $( $variant => $name, )* - } - } -} - -#[derive(HashStable)] -pub struct LanguageItems { - /// Mappings from lang items to their possibly found `DefId`s. - /// The index corresponds to the order in `LangItem`. - pub items: Vec<Option<DefId>>, - /// Lang items that were not found during collection. - pub missing: Vec<LangItem>, -} - -impl LanguageItems { - /// Construct an empty collection of lang items and no missing ones. - pub fn new() -> Self { - fn init_none(_: LangItem) -> Option<DefId> { None } - - Self { - items: vec![$(init_none($variant)),*], - missing: Vec::new(), - } - } - - /// Returns the mappings to the possibly found `DefId`s for each lang item. - pub fn items(&self) -> &[Option<DefId>] { - &*self.items - } - - /// Requires that a given `LangItem` was bound and returns the corresponding `DefId`. - /// If it wasn't bound, e.g. due to a missing `#[lang = "<it.name()>"]`, - /// returns an error message as a string. - pub fn require(&self, it: LangItem) -> Result<DefId, String> { - self.items[it as usize].ok_or_else(|| format!("requires `{}` lang_item", it.name())) - } - - /// Returns the kind of closure that `id`, which is one of the `Fn*` traits, corresponds to. - /// If `id` is not one of the `Fn*` traits, `None` is returned. - pub fn fn_trait_kind(&self, id: DefId) -> Option<ty::ClosureKind> { - match Some(id) { - x if x == self.fn_trait() => Some(ty::ClosureKind::Fn), - x if x == self.fn_mut_trait() => Some(ty::ClosureKind::FnMut), - x if x == self.fn_once_trait() => Some(ty::ClosureKind::FnOnce), - _ => None - } - } - - $( - /// Returns the corresponding `DefId` for the lang item - #[doc = $name] - /// if it exists. - #[allow(dead_code)] - pub fn $method(&self) -> Option<DefId> { - self.items[$variant as usize] - } - )* -} - -struct LanguageItemCollector<'tcx> { - items: LanguageItems, - tcx: TyCtxt<'tcx>, - /// A mapping from the name of the lang item to its order and the form it must be of. - item_refs: FxHashMap<&'static str, (usize, Target)>, -} - -impl ItemLikeVisitor<'v> for LanguageItemCollector<'tcx> { - fn visit_item(&mut self, item: &hir::Item<'_>) { - if let Some((value, span)) = extract(&item.attrs) { - let actual_target = Target::from_item(item); - match self.item_refs.get(&*value.as_str()).cloned() { - // Known lang item with attribute on correct target. - Some((item_index, expected_target)) if actual_target == expected_target => { - let def_id = self.tcx.hir().local_def_id(item.hir_id); - self.collect_item(item_index, def_id); - }, - // Known lang item with attribute on incorrect target. - Some((_, expected_target)) => { - struct_span_err!( - self.tcx.sess, span, E0718, - "`{}` language item must be applied to a {}", - value, expected_target, - ).span_label( - span, - format!( - "attribute should be applied to a {}, not a {}", - expected_target, actual_target, - ), - ).emit(); - }, - // Unknown lang item. - _ => { - struct_span_err!( - self.tcx.sess, span, E0522, - "definition of an unknown language item: `{}`", - value - ).span_label( - span, - format!("definition of unknown language item `{}`", value) - ).emit(); - }, - } - } - } - - fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'_>) { - // At present, lang items are always items, not trait items. - } - - fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'_>) { - // At present, lang items are always items, not impl items. - } -} - -impl LanguageItemCollector<'tcx> { - fn new(tcx: TyCtxt<'tcx>) -> LanguageItemCollector<'tcx> { - let mut item_refs = FxHashMap::default(); - - $( item_refs.insert($name, ($variant as usize, $target)); )* - - LanguageItemCollector { - tcx, - items: LanguageItems::new(), - item_refs, - } - } - - fn collect_item(&mut self, item_index: usize, item_def_id: DefId) { - // Check for duplicates. - if let Some(original_def_id) = self.items.items[item_index] { - if original_def_id != item_def_id { - let name = LangItem::from_u32(item_index as u32).unwrap().name(); - let mut err = match self.tcx.hir().span_if_local(item_def_id) { - Some(span) => struct_span_err!( - self.tcx.sess, - span, - E0152, - "found duplicate lang item `{}`", - name - ), - None => { - match self.tcx.extern_crate(item_def_id) { - Some(ExternCrate {dependency_of, ..}) => { - self.tcx.sess.struct_err(&format!( - "duplicate lang item in crate `{}` (which `{}` depends on): `{}`.", - self.tcx.crate_name(item_def_id.krate), - self.tcx.crate_name(*dependency_of), - name)) - }, - _ => { - self.tcx.sess.struct_err(&format!( - "duplicate lang item in crate `{}`: `{}`.", - self.tcx.crate_name(item_def_id.krate), - name)) - } - } - }, - }; - if let Some(span) = self.tcx.hir().span_if_local(original_def_id) { - err.span_note(span, "the lang item is first defined here"); - } else { - match self.tcx.extern_crate(original_def_id) { - Some(ExternCrate {dependency_of, ..}) => { - err.note(&format!( - "the lang item is first defined in crate `{}` (which `{}` depends on)", - self.tcx.crate_name(original_def_id.krate), - self.tcx.crate_name(*dependency_of))); - }, - _ => { - err.note(&format!("the lang item is first defined in crate `{}`.", - self.tcx.crate_name(original_def_id.krate))); - } - } - } - err.emit(); - } - } - - // Matched. - self.items.items[item_index] = Some(item_def_id); - } -} - -/// Extracts the first `lang = "$name"` out of a list of attributes. -/// The attributes `#[panic_handler]` and `#[alloc_error_handler]` -/// are also extracted out when found. -pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> { - attrs.iter().find_map(|attr| Some(match attr { - _ if attr.check_name(sym::lang) => (attr.value_str()?, attr.span), - _ if attr.check_name(sym::panic_handler) => (sym::panic_impl, attr.span), - _ if attr.check_name(sym::alloc_error_handler) => (sym::oom, attr.span), - _ => return None, - })) -} - -/// Traverses and collects all the lang items in all crates. -pub fn collect<'tcx>(tcx: TyCtxt<'tcx>) -> LanguageItems { - // Initialize the collector. - let mut collector = LanguageItemCollector::new(tcx); - - // Collect lang items in other crates. - for &cnum in tcx.crates().iter() { - for &(def_id, item_index) in tcx.defined_lang_items(cnum).iter() { - collector.collect_item(item_index, def_id); - } - } - - // Collect lang items in this crate. - tcx.hir().krate().visit_all_item_likes(&mut collector); - - // Extract out the found lang items. - let LanguageItemCollector { mut items, .. } = collector; - - // Find all required but not-yet-defined lang items. - weak_lang_items::check_crate(tcx, &mut items); - - items -} - -// End of the macro - } -} - -language_item_table! { -// Variant name, Name, Method name, Target; - BoolImplItem, "bool", bool_impl, Target::Impl; - CharImplItem, "char", char_impl, Target::Impl; - StrImplItem, "str", str_impl, Target::Impl; - SliceImplItem, "slice", slice_impl, Target::Impl; - SliceU8ImplItem, "slice_u8", slice_u8_impl, Target::Impl; - StrAllocImplItem, "str_alloc", str_alloc_impl, Target::Impl; - SliceAllocImplItem, "slice_alloc", slice_alloc_impl, Target::Impl; - SliceU8AllocImplItem, "slice_u8_alloc", slice_u8_alloc_impl, Target::Impl; - ConstPtrImplItem, "const_ptr", const_ptr_impl, Target::Impl; - MutPtrImplItem, "mut_ptr", mut_ptr_impl, Target::Impl; - I8ImplItem, "i8", i8_impl, Target::Impl; - I16ImplItem, "i16", i16_impl, Target::Impl; - I32ImplItem, "i32", i32_impl, Target::Impl; - I64ImplItem, "i64", i64_impl, Target::Impl; - I128ImplItem, "i128", i128_impl, Target::Impl; - IsizeImplItem, "isize", isize_impl, Target::Impl; - U8ImplItem, "u8", u8_impl, Target::Impl; - U16ImplItem, "u16", u16_impl, Target::Impl; - U32ImplItem, "u32", u32_impl, Target::Impl; - U64ImplItem, "u64", u64_impl, Target::Impl; - U128ImplItem, "u128", u128_impl, Target::Impl; - UsizeImplItem, "usize", usize_impl, Target::Impl; - F32ImplItem, "f32", f32_impl, Target::Impl; - F64ImplItem, "f64", f64_impl, Target::Impl; - F32RuntimeImplItem, "f32_runtime", f32_runtime_impl, Target::Impl; - F64RuntimeImplItem, "f64_runtime", f64_runtime_impl, Target::Impl; - - SizedTraitLangItem, "sized", sized_trait, Target::Trait; - UnsizeTraitLangItem, "unsize", unsize_trait, Target::Trait; - // trait injected by #[derive(PartialEq)], (i.e. "Partial EQ"). - StructuralPeqTraitLangItem, "structural_peq", structural_peq_trait, Target::Trait; - // trait injected by #[derive(Eq)], (i.e. "Total EQ"; no, I will not apologize). - StructuralTeqTraitLangItem, "structural_teq", structural_teq_trait, Target::Trait; - CopyTraitLangItem, "copy", copy_trait, Target::Trait; - CloneTraitLangItem, "clone", clone_trait, Target::Trait; - SyncTraitLangItem, "sync", sync_trait, Target::Trait; - FreezeTraitLangItem, "freeze", freeze_trait, Target::Trait; - - DropTraitLangItem, "drop", drop_trait, Target::Trait; - - CoerceUnsizedTraitLangItem, "coerce_unsized", coerce_unsized_trait, Target::Trait; - DispatchFromDynTraitLangItem,"dispatch_from_dyn", dispatch_from_dyn_trait, Target::Trait; - - AddTraitLangItem, "add", add_trait, Target::Trait; - SubTraitLangItem, "sub", sub_trait, Target::Trait; - MulTraitLangItem, "mul", mul_trait, Target::Trait; - DivTraitLangItem, "div", div_trait, Target::Trait; - RemTraitLangItem, "rem", rem_trait, Target::Trait; - NegTraitLangItem, "neg", neg_trait, Target::Trait; - NotTraitLangItem, "not", not_trait, Target::Trait; - BitXorTraitLangItem, "bitxor", bitxor_trait, Target::Trait; - BitAndTraitLangItem, "bitand", bitand_trait, Target::Trait; - BitOrTraitLangItem, "bitor", bitor_trait, Target::Trait; - ShlTraitLangItem, "shl", shl_trait, Target::Trait; - ShrTraitLangItem, "shr", shr_trait, Target::Trait; - AddAssignTraitLangItem, "add_assign", add_assign_trait, Target::Trait; - SubAssignTraitLangItem, "sub_assign", sub_assign_trait, Target::Trait; - MulAssignTraitLangItem, "mul_assign", mul_assign_trait, Target::Trait; - DivAssignTraitLangItem, "div_assign", div_assign_trait, Target::Trait; - RemAssignTraitLangItem, "rem_assign", rem_assign_trait, Target::Trait; - BitXorAssignTraitLangItem, "bitxor_assign", bitxor_assign_trait, Target::Trait; - BitAndAssignTraitLangItem, "bitand_assign", bitand_assign_trait, Target::Trait; - BitOrAssignTraitLangItem, "bitor_assign", bitor_assign_trait, Target::Trait; - ShlAssignTraitLangItem, "shl_assign", shl_assign_trait, Target::Trait; - ShrAssignTraitLangItem, "shr_assign", shr_assign_trait, Target::Trait; - IndexTraitLangItem, "index", index_trait, Target::Trait; - IndexMutTraitLangItem, "index_mut", index_mut_trait, Target::Trait; - - UnsafeCellTypeLangItem, "unsafe_cell", unsafe_cell_type, Target::Struct; - VaListTypeLangItem, "va_list", va_list, Target::Struct; - - DerefTraitLangItem, "deref", deref_trait, Target::Trait; - DerefMutTraitLangItem, "deref_mut", deref_mut_trait, Target::Trait; - ReceiverTraitLangItem, "receiver", receiver_trait, Target::Trait; - - FnTraitLangItem, "fn", fn_trait, Target::Trait; - FnMutTraitLangItem, "fn_mut", fn_mut_trait, Target::Trait; - FnOnceTraitLangItem, "fn_once", fn_once_trait, Target::Trait; - - FutureTraitLangItem, "future_trait", future_trait, Target::Trait; - GeneratorStateLangItem, "generator_state", gen_state, Target::Enum; - GeneratorTraitLangItem, "generator", gen_trait, Target::Trait; - UnpinTraitLangItem, "unpin", unpin_trait, Target::Trait; - PinTypeLangItem, "pin", pin_type, Target::Struct; - - // Don't be fooled by the naming here: this lang item denotes `PartialEq`, not `Eq`. - EqTraitLangItem, "eq", eq_trait, Target::Trait; - PartialOrdTraitLangItem, "partial_ord", partial_ord_trait, Target::Trait; - - // 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, Target::Fn; - PanicBoundsCheckFnLangItem, "panic_bounds_check", panic_bounds_check_fn, Target::Fn; - PanicInfoLangItem, "panic_info", panic_info, Target::Struct; - PanicLocationLangItem, "panic_location", panic_location, Target::Struct; - PanicImplLangItem, "panic_impl", panic_impl, Target::Fn; - // Libstd panic entry point. Necessary for const eval to be able to catch it - BeginPanicFnLangItem, "begin_panic", begin_panic_fn, Target::Fn; - - ExchangeMallocFnLangItem, "exchange_malloc", exchange_malloc_fn, Target::Fn; - BoxFreeFnLangItem, "box_free", box_free_fn, Target::Fn; - DropInPlaceFnLangItem, "drop_in_place", drop_in_place_fn, Target::Fn; - OomLangItem, "oom", oom, Target::Fn; - AllocLayoutLangItem, "alloc_layout", alloc_layout, Target::Struct; - - StartFnLangItem, "start", start_fn, Target::Fn; - - EhPersonalityLangItem, "eh_personality", eh_personality, Target::Fn; - EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume, Target::Fn; - EhCatchTypeinfoLangItem, "eh_catch_typeinfo", eh_catch_typeinfo, Target::Static; - - OwnedBoxLangItem, "owned_box", owned_box, Target::Struct; - - PhantomDataItem, "phantom_data", phantom_data, Target::Struct; - - ManuallyDropItem, "manually_drop", manually_drop, Target::Struct; - - MaybeUninitLangItem, "maybe_uninit", maybe_uninit, Target::Union; - - // Align offset for stride != 1; must not panic. - AlignOffsetLangItem, "align_offset", align_offset_fn, Target::Fn; - - TerminationTraitLangItem, "termination", termination, Target::Trait; - - Arc, "arc", arc, Target::Struct; - Rc, "rc", rc, Target::Struct; -} +pub use rustc_hir::weak_lang_items::link_name; +pub use rustc_hir::{LangItem, LanguageItems}; impl<'tcx> TyCtxt<'tcx> { /// Returns the `DefId` for a given `LangItem`. @@ -417,4 +30,36 @@ impl<'tcx> TyCtxt<'tcx> { } }) } + + pub fn fn_trait_kind_from_lang_item(&self, id: DefId) -> Option<ty::ClosureKind> { + let items = self.lang_items(); + match Some(id) { + x if x == items.fn_trait() => Some(ty::ClosureKind::Fn), + x if x == items.fn_mut_trait() => Some(ty::ClosureKind::FnMut), + x if x == items.fn_once_trait() => Some(ty::ClosureKind::FnOnce), + _ => None, + } + } + + pub fn is_weak_lang_item(&self, item_def_id: DefId) -> bool { + self.lang_items().is_weak_lang_item(item_def_id) + } +} + +/// Returns `true` if the specified `lang_item` doesn't actually need to be +/// present for this compilation. +/// +/// Not all lang items are always required for each compilation, particularly in +/// the case of panic=abort. In these situations some lang items are injected by +/// crates and don't actually need to be defined in libstd. +pub fn whitelisted(tcx: TyCtxt<'_>, lang_item: LangItem) -> bool { + // If we're not compiling with unwinding, we won't actually need these + // symbols. Other panic runtimes ensure that the relevant symbols are + // available to link things together, but they're never exercised. + if tcx.sess.panic_strategy() != PanicStrategy::Unwind { + return lang_item == LangItem::EhPersonalityLangItem + || lang_item == LangItem::EhUnwindResumeLangItem; + } + + false } diff --git a/src/librustc/middle/mod.rs b/src/librustc/middle/mod.rs index c2959766c57..b20f2cf3a85 100644 --- a/src/librustc/middle/mod.rs +++ b/src/librustc/middle/mod.rs @@ -33,4 +33,3 @@ pub mod recursion_limit; pub mod region; pub mod resolve_lifetime; pub mod stability; -pub mod weak_lang_items; diff --git a/src/librustc/middle/weak_lang_items.rs b/src/librustc/middle/weak_lang_items.rs deleted file mode 100644 index 5571f8f2313..00000000000 --- a/src/librustc/middle/weak_lang_items.rs +++ /dev/null @@ -1,167 +0,0 @@ -//! Validity checking for weak lang items - -use crate::middle::lang_items; -use crate::session::config; - -use crate::hir::map::Map; -use crate::ty::TyCtxt; -use rustc_data_structures::fx::FxHashSet; -use rustc_errors::struct_span_err; -use rustc_hir as hir; -use rustc_hir::def_id::DefId; -use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; -use rustc_span::symbol::{sym, Symbol}; -use rustc_span::Span; -use rustc_target::spec::PanicStrategy; -use syntax::ast; - -macro_rules! weak_lang_items { - ($($name:ident, $item:ident, $sym:ident;)*) => ( - -struct Context<'a, 'tcx> { - tcx: TyCtxt<'tcx>, - items: &'a mut lang_items::LanguageItems, -} - -/// Checks the crate for usage of weak lang items, returning a vector of all the -/// language items required by this crate, but not defined yet. -pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>, - items: &mut lang_items::LanguageItems) { - // These are never called by user code, they're generated by the compiler. - // They will never implicitly be added to the `missing` array unless we do - // so here. - 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, _)| { - $(if name == sym::$name { - Some(sym::$sym) - } else)* { - None - } - }) -} - -/// Returns `true` if the specified `lang_item` doesn't actually need to be -/// present for this compilation. -/// -/// Not all lang items are always required for each compilation, particularly in -/// the case of panic=abort. In these situations some lang items are injected by -/// crates and don't actually need to be defined in libstd. -pub fn whitelisted(tcx: TyCtxt<'_>, lang_item: lang_items::LangItem) -> bool { - // If we're not compiling with unwinding, we won't actually need these - // symbols. Other panic runtimes ensure that the relevant symbols are - // available to link things together, but they're never exercised. - if tcx.sess.panic_strategy() != PanicStrategy::Unwind { - return lang_item == lang_items::EhPersonalityLangItem || - lang_item == lang_items::EhUnwindResumeLangItem - } - - false -} - -fn verify<'tcx>(tcx: TyCtxt<'tcx>, - items: &lang_items::LanguageItems) { - // We only need to check for the presence of weak lang items if we're - // emitting something that's not an rlib. - 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: Symbol, span: Span) { - $(if name == sym::$name { - if self.items.$name().is_none() { - self.items.missing.push(lang_items::$item); - } - } else)* { - struct_span_err!( - self.tcx.sess, span, E0264, - "unknown external lang item: `{}`", - name - ) - .emit(); - } - } -} - -impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> { - type Map = Map<'v>; - - fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, Map<'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, i.span); - } - intravisit::walk_foreign_item(self, i) - } -} - -impl<'tcx> TyCtxt<'tcx> { - 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; -} diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs index 17337ff0c92..bf82d743c2b 100644 --- a/src/librustc/traits/select.rs +++ b/src/librustc/traits/select.rs @@ -1634,7 +1634,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { obligation: &TraitObligation<'tcx>, candidates: &mut SelectionCandidateSet<'tcx>, ) -> Result<(), SelectionError<'tcx>> { - let kind = match self.tcx().lang_items().fn_trait_kind(obligation.predicate.def_id()) { + let kind = match self.tcx().fn_trait_kind_from_lang_item(obligation.predicate.def_id()) { Some(k) => k, None => { return Ok(()); @@ -1677,7 +1677,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { candidates: &mut SelectionCandidateSet<'tcx>, ) -> Result<(), SelectionError<'tcx>> { // We provide impl of all fn traits for fn pointers. - if self.tcx().lang_items().fn_trait_kind(obligation.predicate.def_id()).is_none() { + if self.tcx().fn_trait_kind_from_lang_item(obligation.predicate.def_id()).is_none() { return Ok(()); } @@ -2889,8 +2889,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let kind = self .tcx() - .lang_items() - .fn_trait_kind(obligation.predicate.def_id()) + .fn_trait_kind_from_lang_item(obligation.predicate.def_id()) .unwrap_or_else(|| bug!("closure candidate for non-fn trait {:?}", obligation)); // Okay to skip binder because the substs on closure types never diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs index f2ad01b3d59..2adf7086417 100644 --- a/src/librustc/ty/context.rs +++ b/src/librustc/ty/context.rs @@ -2716,10 +2716,6 @@ pub fn provide(providers: &mut ty::query::Providers<'_>) { assert_eq!(id, LOCAL_CRATE); tcx.crate_name }; - providers.get_lang_items = |tcx, id| { - assert_eq!(id, LOCAL_CRATE); - tcx.arena.alloc(middle::lang_items::collect(tcx)) - }; providers.maybe_unused_trait_import = |tcx, id| tcx.maybe_unused_trait_imports.contains(&id); providers.maybe_unused_extern_crates = |tcx, cnum| { assert_eq!(cnum, LOCAL_CRATE); diff --git a/src/librustc/ty/instance.rs b/src/librustc/ty/instance.rs index c7f19513f66..b5e17661c5d 100644 --- a/src/librustc/ty/instance.rs +++ b/src/librustc/ty/instance.rs @@ -450,7 +450,7 @@ fn resolve_associated_item<'tcx>( substs: generator_data.substs, }), traits::VtableClosure(closure_data) => { - let trait_closure_kind = tcx.lang_items().fn_trait_kind(trait_id).unwrap(); + let trait_closure_kind = tcx.fn_trait_kind_from_lang_item(trait_id).unwrap(); Some(Instance::resolve_closure( tcx, closure_data.closure_def_id, diff --git a/src/librustc/ty/print/pretty.rs b/src/librustc/ty/print/pretty.rs index 0da680d1f91..274482cba64 100644 --- a/src/librustc/ty/print/pretty.rs +++ b/src/librustc/ty/print/pretty.rs @@ -724,7 +724,7 @@ pub trait PrettyPrinter<'tcx>: let mut resugared = false; // Special-case `Fn(...) -> ...` and resugar it. - let fn_trait_kind = self.tcx().lang_items().fn_trait_kind(principal.def_id); + let fn_trait_kind = self.tcx().fn_trait_kind_from_lang_item(principal.def_id); if !self.tcx().sess.verbose() && fn_trait_kind.is_some() { if let ty::Tuple(ref args) = principal.substs.type_at(0).kind { let mut projections = predicates.projection_bounds(); diff --git a/src/librustc_codegen_ssa/base.rs b/src/librustc_codegen_ssa/base.rs index 90015091384..e9431d94863 100644 --- a/src/librustc_codegen_ssa/base.rs +++ b/src/librustc_codegen_ssa/base.rs @@ -28,8 +28,8 @@ use crate::{CachedModuleCodegen, CrateInfo, MemFlags, ModuleCodegen, ModuleKind} use rustc::middle::codegen_fn_attrs::CodegenFnAttrs; use rustc::middle::cstore::EncodedMetadata; use rustc::middle::cstore::{self, LinkagePreference}; +use rustc::middle::lang_items; use rustc::middle::lang_items::StartFnLangItem; -use rustc::middle::weak_lang_items; use rustc::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem}; use rustc::session::config::{self, EntryFnType, Lto}; use rustc::session::Session; @@ -847,11 +847,8 @@ impl CrateInfo { // No need to look for lang items that are whitelisted and don't // actually need to exist. - let missing = missing - .iter() - .cloned() - .filter(|&l| !weak_lang_items::whitelisted(tcx, l)) - .collect(); + let missing = + missing.iter().cloned().filter(|&l| !lang_items::whitelisted(tcx, l)).collect(); info.missing_lang_items.insert(cnum, missing); } diff --git a/src/librustc_data_structures/macros.rs b/src/librustc_data_structures/macros.rs index 83e6dbedee2..67fbe3058cd 100644 --- a/src/librustc_data_structures/macros.rs +++ b/src/librustc_data_structures/macros.rs @@ -17,3 +17,41 @@ macro_rules! static_assert_size { const _: [(); $size] = [(); ::std::mem::size_of::<$ty>()]; }; } + +#[macro_export] +macro_rules! enum_from_u32 { + ($(#[$attr:meta])* pub enum $name:ident { + $($variant:ident = $e:expr,)* + }) => { + $(#[$attr])* + pub enum $name { + $($variant = $e),* + } + + impl $name { + pub fn from_u32(u: u32) -> Option<$name> { + $(if u == $name::$variant as u32 { + return Some($name::$variant) + })* + None + } + } + }; + ($(#[$attr:meta])* pub enum $name:ident { + $($variant:ident,)* + }) => { + $(#[$attr])* + pub enum $name { + $($variant,)* + } + + impl $name { + pub fn from_u32(u: u32) -> Option<$name> { + $(if u == $name::$variant as u32 { + return Some($name::$variant) + })* + None + } + } + } +} diff --git a/src/librustc_hir/Cargo.toml b/src/librustc_hir/Cargo.toml index 3ae943a4ce0..cff64132532 100644 --- a/src/librustc_hir/Cargo.toml +++ b/src/librustc_hir/Cargo.toml @@ -19,4 +19,5 @@ rustc_span = { path = "../librustc_span" } rustc_errors = { path = "../librustc_errors" } rustc_serialize = { path = "../libserialize", package = "serialize" } syntax = { path = "../libsyntax" } +lazy_static = "1" smallvec = { version = "1.0", features = ["union", "may_dangle"] } diff --git a/src/librustc_hir/lang_items.rs b/src/librustc_hir/lang_items.rs new file mode 100644 index 00000000000..cb5ebba4633 --- /dev/null +++ b/src/librustc_hir/lang_items.rs @@ -0,0 +1,261 @@ +//! Defines 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 crate::def_id::DefId; +use crate::Target; + +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; +use rustc_macros::HashStable_Generic; +use rustc_span::symbol::{sym, Symbol}; +use rustc_span::Span; +use syntax::ast; + +use lazy_static::lazy_static; + +// 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! language_item_table { + ( + $( $variant:ident, $name:expr, $method:ident, $target:path; )* + ) => { + + enum_from_u32! { + /// A representation of all the valid language items in Rust. + #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)] + pub enum LangItem { + $($variant,)* + } + } + + impl LangItem { + /// Returns the `name` in `#[lang = "$name"]`. + /// For example, `LangItem::EqTraitLangItem`, + /// that is `#[lang = "eq"]` would result in `"eq"`. + pub fn name(self) -> &'static str { + match self { + $( $variant => $name, )* + } + } + } + + #[derive(HashStable_Generic)] + pub struct LanguageItems { + /// Mappings from lang items to their possibly found `DefId`s. + /// The index corresponds to the order in `LangItem`. + pub items: Vec<Option<DefId>>, + /// Lang items that were not found during collection. + pub missing: Vec<LangItem>, + } + + impl LanguageItems { + /// Construct an empty collection of lang items and no missing ones. + pub fn new() -> Self { + fn init_none(_: LangItem) -> Option<DefId> { None } + + Self { + items: vec![$(init_none($variant)),*], + missing: Vec::new(), + } + } + + /// Returns the mappings to the possibly found `DefId`s for each lang item. + pub fn items(&self) -> &[Option<DefId>] { + &*self.items + } + + /// Requires that a given `LangItem` was bound and returns the corresponding `DefId`. + /// If it wasn't bound, e.g. due to a missing `#[lang = "<it.name()>"]`, + /// returns an error message as a string. + pub fn require(&self, it: LangItem) -> Result<DefId, String> { + self.items[it as usize].ok_or_else(|| format!("requires `{}` lang_item", it.name())) + } + + $( + /// Returns the corresponding `DefId` for the lang item + #[doc = $name] + /// if it exists. + #[allow(dead_code)] + pub fn $method(&self) -> Option<DefId> { + self.items[$variant as usize] + } + )* + } + + lazy_static! { + /// A mapping from the name of the lang item to its order and the form it must be of. + pub static ref ITEM_REFS: FxHashMap<&'static str, (usize, Target)> = { + let mut item_refs = FxHashMap::default(); + $( item_refs.insert($name, ($variant as usize, $target)); )* + item_refs + }; + } + +// End of the macro + } +} + +impl<CTX> HashStable<CTX> for LangItem { + fn hash_stable(&self, _: &mut CTX, hasher: &mut StableHasher) { + ::std::hash::Hash::hash(self, hasher); + } +} + +/// Extracts the first `lang = "$name"` out of a list of attributes. +/// The attributes `#[panic_handler]` and `#[alloc_error_handler]` +/// are also extracted out when found. +pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> { + attrs.iter().find_map(|attr| { + Some(match attr { + _ if attr.check_name(sym::lang) => (attr.value_str()?, attr.span), + _ if attr.check_name(sym::panic_handler) => (sym::panic_impl, attr.span), + _ if attr.check_name(sym::alloc_error_handler) => (sym::oom, attr.span), + _ => return None, + }) + }) +} + +language_item_table! { +// Variant name, Name, Method name, Target; + BoolImplItem, "bool", bool_impl, Target::Impl; + CharImplItem, "char", char_impl, Target::Impl; + StrImplItem, "str", str_impl, Target::Impl; + SliceImplItem, "slice", slice_impl, Target::Impl; + SliceU8ImplItem, "slice_u8", slice_u8_impl, Target::Impl; + StrAllocImplItem, "str_alloc", str_alloc_impl, Target::Impl; + SliceAllocImplItem, "slice_alloc", slice_alloc_impl, Target::Impl; + SliceU8AllocImplItem, "slice_u8_alloc", slice_u8_alloc_impl, Target::Impl; + ConstPtrImplItem, "const_ptr", const_ptr_impl, Target::Impl; + MutPtrImplItem, "mut_ptr", mut_ptr_impl, Target::Impl; + I8ImplItem, "i8", i8_impl, Target::Impl; + I16ImplItem, "i16", i16_impl, Target::Impl; + I32ImplItem, "i32", i32_impl, Target::Impl; + I64ImplItem, "i64", i64_impl, Target::Impl; + I128ImplItem, "i128", i128_impl, Target::Impl; + IsizeImplItem, "isize", isize_impl, Target::Impl; + U8ImplItem, "u8", u8_impl, Target::Impl; + U16ImplItem, "u16", u16_impl, Target::Impl; + U32ImplItem, "u32", u32_impl, Target::Impl; + U64ImplItem, "u64", u64_impl, Target::Impl; + U128ImplItem, "u128", u128_impl, Target::Impl; + UsizeImplItem, "usize", usize_impl, Target::Impl; + F32ImplItem, "f32", f32_impl, Target::Impl; + F64ImplItem, "f64", f64_impl, Target::Impl; + F32RuntimeImplItem, "f32_runtime", f32_runtime_impl, Target::Impl; + F64RuntimeImplItem, "f64_runtime", f64_runtime_impl, Target::Impl; + + SizedTraitLangItem, "sized", sized_trait, Target::Trait; + UnsizeTraitLangItem, "unsize", unsize_trait, Target::Trait; + // trait injected by #[derive(PartialEq)], (i.e. "Partial EQ"). + StructuralPeqTraitLangItem, "structural_peq", structural_peq_trait, Target::Trait; + // trait injected by #[derive(Eq)], (i.e. "Total EQ"; no, I will not apologize). + StructuralTeqTraitLangItem, "structural_teq", structural_teq_trait, Target::Trait; + CopyTraitLangItem, "copy", copy_trait, Target::Trait; + CloneTraitLangItem, "clone", clone_trait, Target::Trait; + SyncTraitLangItem, "sync", sync_trait, Target::Trait; + FreezeTraitLangItem, "freeze", freeze_trait, Target::Trait; + + DropTraitLangItem, "drop", drop_trait, Target::Trait; + + CoerceUnsizedTraitLangItem, "coerce_unsized", coerce_unsized_trait, Target::Trait; + DispatchFromDynTraitLangItem,"dispatch_from_dyn", dispatch_from_dyn_trait, Target::Trait; + + AddTraitLangItem, "add", add_trait, Target::Trait; + SubTraitLangItem, "sub", sub_trait, Target::Trait; + MulTraitLangItem, "mul", mul_trait, Target::Trait; + DivTraitLangItem, "div", div_trait, Target::Trait; + RemTraitLangItem, "rem", rem_trait, Target::Trait; + NegTraitLangItem, "neg", neg_trait, Target::Trait; + NotTraitLangItem, "not", not_trait, Target::Trait; + BitXorTraitLangItem, "bitxor", bitxor_trait, Target::Trait; + BitAndTraitLangItem, "bitand", bitand_trait, Target::Trait; + BitOrTraitLangItem, "bitor", bitor_trait, Target::Trait; + ShlTraitLangItem, "shl", shl_trait, Target::Trait; + ShrTraitLangItem, "shr", shr_trait, Target::Trait; + AddAssignTraitLangItem, "add_assign", add_assign_trait, Target::Trait; + SubAssignTraitLangItem, "sub_assign", sub_assign_trait, Target::Trait; + MulAssignTraitLangItem, "mul_assign", mul_assign_trait, Target::Trait; + DivAssignTraitLangItem, "div_assign", div_assign_trait, Target::Trait; + RemAssignTraitLangItem, "rem_assign", rem_assign_trait, Target::Trait; + BitXorAssignTraitLangItem, "bitxor_assign", bitxor_assign_trait, Target::Trait; + BitAndAssignTraitLangItem, "bitand_assign", bitand_assign_trait, Target::Trait; + BitOrAssignTraitLangItem, "bitor_assign", bitor_assign_trait, Target::Trait; + ShlAssignTraitLangItem, "shl_assign", shl_assign_trait, Target::Trait; + ShrAssignTraitLangItem, "shr_assign", shr_assign_trait, Target::Trait; + IndexTraitLangItem, "index", index_trait, Target::Trait; + IndexMutTraitLangItem, "index_mut", index_mut_trait, Target::Trait; + + UnsafeCellTypeLangItem, "unsafe_cell", unsafe_cell_type, Target::Struct; + VaListTypeLangItem, "va_list", va_list, Target::Struct; + + DerefTraitLangItem, "deref", deref_trait, Target::Trait; + DerefMutTraitLangItem, "deref_mut", deref_mut_trait, Target::Trait; + ReceiverTraitLangItem, "receiver", receiver_trait, Target::Trait; + + FnTraitLangItem, "fn", fn_trait, Target::Trait; + FnMutTraitLangItem, "fn_mut", fn_mut_trait, Target::Trait; + FnOnceTraitLangItem, "fn_once", fn_once_trait, Target::Trait; + + FutureTraitLangItem, "future_trait", future_trait, Target::Trait; + GeneratorStateLangItem, "generator_state", gen_state, Target::Enum; + GeneratorTraitLangItem, "generator", gen_trait, Target::Trait; + UnpinTraitLangItem, "unpin", unpin_trait, Target::Trait; + PinTypeLangItem, "pin", pin_type, Target::Struct; + + // Don't be fooled by the naming here: this lang item denotes `PartialEq`, not `Eq`. + EqTraitLangItem, "eq", eq_trait, Target::Trait; + PartialOrdTraitLangItem, "partial_ord", partial_ord_trait, Target::Trait; + + // 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, Target::Fn; + PanicBoundsCheckFnLangItem, "panic_bounds_check", panic_bounds_check_fn, Target::Fn; + PanicInfoLangItem, "panic_info", panic_info, Target::Struct; + PanicLocationLangItem, "panic_location", panic_location, Target::Struct; + PanicImplLangItem, "panic_impl", panic_impl, Target::Fn; + // Libstd panic entry point. Necessary for const eval to be able to catch it + BeginPanicFnLangItem, "begin_panic", begin_panic_fn, Target::Fn; + + ExchangeMallocFnLangItem, "exchange_malloc", exchange_malloc_fn, Target::Fn; + BoxFreeFnLangItem, "box_free", box_free_fn, Target::Fn; + DropInPlaceFnLangItem, "drop_in_place", drop_in_place_fn, Target::Fn; + OomLangItem, "oom", oom, Target::Fn; + AllocLayoutLangItem, "alloc_layout", alloc_layout, Target::Struct; + + StartFnLangItem, "start", start_fn, Target::Fn; + + EhPersonalityLangItem, "eh_personality", eh_personality, Target::Fn; + EhUnwindResumeLangItem, "eh_unwind_resume", eh_unwind_resume, Target::Fn; + EhCatchTypeinfoLangItem, "eh_catch_typeinfo", eh_catch_typeinfo, Target::Static; + + OwnedBoxLangItem, "owned_box", owned_box, Target::Struct; + + PhantomDataItem, "phantom_data", phantom_data, Target::Struct; + + ManuallyDropItem, "manually_drop", manually_drop, Target::Struct; + + MaybeUninitLangItem, "maybe_uninit", maybe_uninit, Target::Union; + + // Align offset for stride != 1; must not panic. + AlignOffsetLangItem, "align_offset", align_offset_fn, Target::Fn; + + TerminationTraitLangItem, "termination", termination, Target::Trait; + + Arc, "arc", arc, Target::Struct; + Rc, "rc", rc, Target::Struct; +} diff --git a/src/librustc_hir/lib.rs b/src/librustc_hir/lib.rs index e4edd34bd6e..d958dfc681b 100644 --- a/src/librustc_hir/lib.rs +++ b/src/librustc_hir/lib.rs @@ -17,9 +17,15 @@ mod hir; pub mod hir_id; pub mod intravisit; pub mod itemlikevisit; +pub mod lang_items; pub mod pat_util; pub mod print; mod stable_hash_impls; +mod target; +pub mod weak_lang_items; + pub use hir::*; pub use hir_id::*; +pub use lang_items::{LangItem, LanguageItems}; pub use stable_hash_impls::HashStableContext; +pub use target::{MethodKind, Target}; diff --git a/src/librustc/hir/check_attr.rs b/src/librustc_hir/target.rs index db5e31981c0..501976fc3cb 100644 --- a/src/librustc/hir/check_attr.rs +++ b/src/librustc_hir/target.rs @@ -4,8 +4,8 @@ //! conflicts between multiple such attributes attached to the same //! item. -use rustc_hir as hir; -use rustc_hir::{Item, ItemKind, TraitItem, TraitItemKind}; +use crate::hir; +use crate::{Item, ItemKind, TraitItem, TraitItemKind}; use std::fmt::{self, Display}; diff --git a/src/librustc_hir/weak_lang_items.rs b/src/librustc_hir/weak_lang_items.rs new file mode 100644 index 00000000000..79182caae8c --- /dev/null +++ b/src/librustc_hir/weak_lang_items.rs @@ -0,0 +1,48 @@ +//! Validity checking for weak lang items + +use crate::def_id::DefId; +use crate::{lang_items, LangItem, LanguageItems}; + +use rustc_data_structures::fx::FxHashMap; +use rustc_span::symbol::{sym, Symbol}; +use syntax::ast; + +use lazy_static::lazy_static; + +macro_rules! weak_lang_items { + ($($name:ident, $item:ident, $sym:ident;)*) => ( + +lazy_static! { + pub static ref WEAK_ITEMS_REFS: FxHashMap<Symbol, LangItem> = { + let mut map = FxHashMap::default(); + $(map.insert(sym::$name, lang_items::$item);)* + map + }; +} + +pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol> { + lang_items::extract(attrs).and_then(|(name, _)| { + $(if name == sym::$name { + Some(sym::$sym) + } else)* { + None + } + }) +} + +impl LanguageItems { + pub fn is_weak_lang_item(&self, item_def_id: DefId) -> bool { + let did = Some(item_def_id); + + $(self.$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; +} diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs index a8c66be359c..bfd30ff5da5 100644 --- a/src/librustc_mir/shim.rs +++ b/src/librustc_mir/shim.rs @@ -40,7 +40,7 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> &'tcx ), ty::InstanceDef::FnPtrShim(def_id, ty) => { let trait_ = tcx.trait_of_item(def_id).unwrap(); - let adjustment = match tcx.lang_items().fn_trait_kind(trait_) { + let adjustment = match tcx.fn_trait_kind_from_lang_item(trait_) { Some(ty::ClosureKind::FnOnce) => Adjustment::Identity, Some(ty::ClosureKind::FnMut) | Some(ty::ClosureKind::Fn) => Adjustment::Deref, None => bug!("fn pointer {:?} is not an fn", ty), diff --git a/src/librustc_passes/check_attr.rs b/src/librustc_passes/check_attr.rs index 855970d9342..5cabf3c0262 100644 --- a/src/librustc_passes/check_attr.rs +++ b/src/librustc_passes/check_attr.rs @@ -4,7 +4,6 @@ //! conflicts between multiple such attributes attached to the same //! item. -use rustc::hir::check_attr::{MethodKind, Target}; use rustc::hir::map::Map; use rustc::ty::query::Providers; use rustc::ty::TyCtxt; @@ -15,6 +14,7 @@ use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; use rustc_hir::DUMMY_HIR_ID; use rustc_hir::{self, HirId, Item, ItemKind, TraitItem}; +use rustc_hir::{MethodKind, Target}; use rustc_session::lint::builtin::{CONFLICTING_REPR_HINTS, UNUSED_ATTRIBUTES}; use rustc_session::parse::feature_err; use rustc_span::symbol::sym; diff --git a/src/librustc_passes/lang_items.rs b/src/librustc_passes/lang_items.rs new file mode 100644 index 00000000000..5f5acc7fdf8 --- /dev/null +++ b/src/librustc_passes/lang_items.rs @@ -0,0 +1,174 @@ +//! 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. + +use crate::weak_lang_items; + +use rustc::middle::cstore::ExternCrate; +use rustc::ty::TyCtxt; + +use rustc_errors::struct_span_err; +use rustc_hir as hir; +use rustc_hir::def_id::{DefId, LOCAL_CRATE}; +use rustc_hir::itemlikevisit::ItemLikeVisitor; +use rustc_hir::lang_items::{extract, ITEM_REFS}; +use rustc_hir::{LangItem, LanguageItems, Target}; + +use rustc::ty::query::Providers; + +struct LanguageItemCollector<'tcx> { + items: LanguageItems, + tcx: TyCtxt<'tcx>, +} + +impl ItemLikeVisitor<'v> for LanguageItemCollector<'tcx> { + fn visit_item(&mut self, item: &hir::Item<'_>) { + if let Some((value, span)) = extract(&item.attrs) { + let actual_target = Target::from_item(item); + match ITEM_REFS.get(&*value.as_str()).cloned() { + // Known lang item with attribute on correct target. + Some((item_index, expected_target)) if actual_target == expected_target => { + let def_id = self.tcx.hir().local_def_id(item.hir_id); + self.collect_item(item_index, def_id); + } + // Known lang item with attribute on incorrect target. + Some((_, expected_target)) => { + struct_span_err!( + self.tcx.sess, + span, + E0718, + "`{}` language item must be applied to a {}", + value, + expected_target, + ) + .span_label( + span, + format!( + "attribute should be applied to a {}, not a {}", + expected_target, actual_target, + ), + ) + .emit(); + } + // Unknown lang item. + _ => { + struct_span_err!( + self.tcx.sess, + span, + E0522, + "definition of an unknown language item: `{}`", + value + ) + .span_label(span, format!("definition of unknown language item `{}`", value)) + .emit(); + } + } + } + } + + fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'_>) { + // At present, lang items are always items, not trait items. + } + + fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'_>) { + // At present, lang items are always items, not impl items. + } +} + +impl LanguageItemCollector<'tcx> { + fn new(tcx: TyCtxt<'tcx>) -> LanguageItemCollector<'tcx> { + LanguageItemCollector { tcx, items: LanguageItems::new() } + } + + fn collect_item(&mut self, item_index: usize, item_def_id: DefId) { + // Check for duplicates. + if let Some(original_def_id) = self.items.items[item_index] { + if original_def_id != item_def_id { + let name = LangItem::from_u32(item_index as u32).unwrap().name(); + let mut err = match self.tcx.hir().span_if_local(item_def_id) { + Some(span) => struct_span_err!( + self.tcx.sess, + span, + E0152, + "found duplicate lang item `{}`", + name + ), + None => match self.tcx.extern_crate(item_def_id) { + Some(ExternCrate { dependency_of, .. }) => { + self.tcx.sess.struct_err(&format!( + "duplicate lang item in crate `{}` (which `{}` depends on): `{}`.", + self.tcx.crate_name(item_def_id.krate), + self.tcx.crate_name(*dependency_of), + name + )) + } + _ => self.tcx.sess.struct_err(&format!( + "duplicate lang item in crate `{}`: `{}`.", + self.tcx.crate_name(item_def_id.krate), + name + )), + }, + }; + if let Some(span) = self.tcx.hir().span_if_local(original_def_id) { + err.span_note(span, "the lang item is first defined here"); + } else { + match self.tcx.extern_crate(original_def_id) { + Some(ExternCrate { dependency_of, .. }) => { + err.note(&format!( + "the lang item is first defined in crate `{}` (which `{}` depends on)", + self.tcx.crate_name(original_def_id.krate), + self.tcx.crate_name(*dependency_of) + )); + } + _ => { + err.note(&format!( + "the lang item is first defined in crate `{}`.", + self.tcx.crate_name(original_def_id.krate) + )); + } + } + } + err.emit(); + } + } + + // Matched. + self.items.items[item_index] = Some(item_def_id); + } +} + +/// Traverses and collects all the lang items in all crates. +fn collect<'tcx>(tcx: TyCtxt<'tcx>) -> LanguageItems { + // Initialize the collector. + let mut collector = LanguageItemCollector::new(tcx); + + // Collect lang items in other crates. + for &cnum in tcx.crates().iter() { + for &(def_id, item_index) in tcx.defined_lang_items(cnum).iter() { + collector.collect_item(item_index, def_id); + } + } + + // Collect lang items in this crate. + tcx.hir().krate().visit_all_item_likes(&mut collector); + + // Extract out the found lang items. + let LanguageItemCollector { mut items, .. } = collector; + + // Find all required but not-yet-defined lang items. + weak_lang_items::check_crate(tcx, &mut items); + + items +} + +pub fn provide(providers: &mut Providers<'_>) { + providers.get_lang_items = |tcx, id| { + assert_eq!(id, LOCAL_CRATE); + tcx.arena.alloc(collect(tcx)) + }; +} diff --git a/src/librustc_passes/lib.rs b/src/librustc_passes/lib.rs index c5e5bc96915..afafbacb8fa 100644 --- a/src/librustc_passes/lib.rs +++ b/src/librustc_passes/lib.rs @@ -23,6 +23,7 @@ mod diagnostic_items; pub mod entry; pub mod hir_stats; mod intrinsicck; +mod lang_items; pub mod layout_test; mod lib_features; mod liveness; @@ -31,12 +32,14 @@ mod reachable; mod region; pub mod stability; mod upvars; +mod weak_lang_items; pub fn provide(providers: &mut Providers<'_>) { check_attr::provide(providers); check_const::provide(providers); diagnostic_items::provide(providers); entry::provide(providers); + lang_items::provide(providers); lib_features::provide(providers); loops::provide(providers); liveness::provide(providers); diff --git a/src/librustc_passes/weak_lang_items.rs b/src/librustc_passes/weak_lang_items.rs new file mode 100644 index 00000000000..010712c28ba --- /dev/null +++ b/src/librustc_passes/weak_lang_items.rs @@ -0,0 +1,103 @@ +//! Validity checking for weak lang items + +use rustc::middle::lang_items; +use rustc::middle::lang_items::whitelisted; +use rustc::session::config; + +use rustc::hir::map::Map; +use rustc::ty::TyCtxt; +use rustc_data_structures::fx::FxHashSet; +use rustc_errors::struct_span_err; +use rustc_hir as hir; +use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; +use rustc_hir::weak_lang_items::WEAK_ITEMS_REFS; +use rustc_span::symbol::Symbol; +use rustc_span::Span; + +struct Context<'a, 'tcx> { + tcx: TyCtxt<'tcx>, + items: &'a mut lang_items::LanguageItems, +} + +/// Checks the crate for usage of weak lang items, returning a vector of all the +/// language items required by this crate, but not defined yet. +pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>, items: &mut lang_items::LanguageItems) { + // These are never called by user code, they're generated by the compiler. + // They will never implicitly be added to the `missing` array unless we do + // so here. + 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); +} + +fn verify<'tcx>(tcx: TyCtxt<'tcx>, items: &lang_items::LanguageItems) { + // We only need to check for the presence of weak lang items if we're + // emitting something that's not an rlib. + 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); + } + } + + for (name, &item) in WEAK_ITEMS_REFS.iter() { + if missing.contains(&item) && !whitelisted(tcx, item) && items.require(item).is_err() { + if item == lang_items::PanicImplLangItem { + tcx.sess.err(&format!("`#[panic_handler]` function required, but not found")); + } else if 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: `{}`", name)); + } + } + } +} + +impl<'a, 'tcx> Context<'a, 'tcx> { + fn register(&mut self, name: Symbol, span: Span) { + if let Some(&item) = WEAK_ITEMS_REFS.get(&name) { + if self.items.require(item).is_err() { + self.items.missing.push(item); + } + } else { + struct_span_err!(self.tcx.sess, span, E0264, "unknown external lang item: `{}`", name) + .emit(); + } + } +} + +impl<'a, 'tcx, 'v> Visitor<'v> for Context<'a, 'tcx> { + type Map = Map<'v>; + + fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, Map<'v>> { + NestedVisitorMap::None + } + + fn visit_foreign_item(&mut self, i: &hir::ForeignItem<'_>) { + if let Some((lang_item, _)) = hir::lang_items::extract(&i.attrs) { + self.register(lang_item, i.span); + } + intravisit::walk_foreign_item(self, i) + } +} diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs index 707125b3fd5..396534b3cae 100644 --- a/src/librustc_typeck/check/closure.rs +++ b/src/librustc_typeck/check/closure.rs @@ -176,7 +176,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { .next(); let kind = object_type .principal_def_id() - .and_then(|did| self.tcx.lang_items().fn_trait_kind(did)); + .and_then(|did| self.tcx.fn_trait_kind_from_lang_item(did)); (sig, kind) } ty::Infer(ty::TyVar(vid)) => self.deduce_expectations_from_obligations(vid), @@ -214,7 +214,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { // many viable options, so pick the most restrictive. let expected_kind = self .obligations_for_self_ty(expected_vid) - .filter_map(|(tr, _)| self.tcx.lang_items().fn_trait_kind(tr.def_id())) + .filter_map(|(tr, _)| self.tcx.fn_trait_kind_from_lang_item(tr.def_id())) .fold(None, |best, cur| Some(best.map_or(cur, |best| cmp::min(best, cur)))); (expected_sig, expected_kind) @@ -237,7 +237,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { let trait_ref = projection.to_poly_trait_ref(tcx); - let is_fn = tcx.lang_items().fn_trait_kind(trait_ref.def_id()).is_some(); + let is_fn = tcx.fn_trait_kind_from_lang_item(trait_ref.def_id()).is_some(); let gen_trait = tcx.require_lang_item(lang_items::GeneratorTraitLangItem, cause_span); let is_gen = gen_trait == trait_ref.def_id(); if !is_fn && !is_gen { diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs index b661006d1dd..ea0e4719a24 100644 --- a/src/librustc_typeck/collect.rs +++ b/src/librustc_typeck/collect.rs @@ -20,8 +20,8 @@ use crate::astconv::{AstConv, Bounds, SizedByDefault}; use crate::check::intrinsic::intrinsic_operation_unsafety; use crate::constrained_generic_params as cgp; use crate::lint; +use crate::middle::lang_items; use crate::middle::resolve_lifetime as rl; -use crate::middle::weak_lang_items; use rustc::hir::map::blocks::FnLikeNode; use rustc::hir::map::Map; use rustc::middle::codegen_fn_attrs::{CodegenFnAttrFlags, CodegenFnAttrs}; @@ -2977,7 +2977,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, id: DefId) -> CodegenFnAttrs { if tcx.is_weak_lang_item(id) { codegen_fn_attrs.flags |= CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL; } - if let Some(name) = weak_lang_items::link_name(&attrs) { + if let Some(name) = lang_items::link_name(&attrs) { codegen_fn_attrs.export_name = Some(name); codegen_fn_attrs.link_name = Some(name); } diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs index 356660763a7..ef357056504 100644 --- a/src/librustdoc/clean/utils.rs +++ b/src/librustdoc/clean/utils.rs @@ -138,7 +138,7 @@ pub fn external_generic_args( match trait_did { // Attempt to sugar an external path like Fn<(A, B,), C> to Fn(A, B) -> C - Some(did) if cx.tcx.lang_items().fn_trait_kind(did).is_some() => { + Some(did) if cx.tcx.fn_trait_kind_from_lang_item(did).is_some() => { assert!(ty_kind.is_some()); let inputs = match ty_kind { Some(ty::Tuple(ref tys)) => tys.iter().map(|t| t.expect_ty().clean(cx)).collect(), |