| //! 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. |
| |
| use crate::def_id::DefId; |
| use crate::{MethodKind, Target}; |
| |
| use rustc_ast as ast; |
| use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
| use rustc_macros::HashStable_Generic; |
| use rustc_span::symbol::{kw, sym, Symbol}; |
| use rustc_span::Span; |
| |
| /// All of the language items, defined or not. |
| /// Defined lang items can come from the current crate or its dependencies. |
| #[derive(HashStable_Generic, Debug)] |
| pub struct LanguageItems { |
| /// Mappings from lang items to their possibly found [`DefId`]s. |
| /// The index corresponds to the order in [`LangItem`]. |
| items: [Option<DefId>; std::mem::variant_count::<LangItem>()], |
| /// 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 { |
| Self { items: [None; std::mem::variant_count::<LangItem>()], missing: Vec::new() } |
| } |
| |
| pub fn get(&self, item: LangItem) -> Option<DefId> { |
| self.items[item as usize] |
| } |
| |
| pub fn set(&mut self, item: LangItem, def_id: DefId) { |
| self.items[item as usize] = Some(def_id); |
| } |
| |
| pub fn iter(&self) -> impl Iterator<Item = (LangItem, DefId)> + '_ { |
| self.items |
| .iter() |
| .enumerate() |
| .filter_map(|(i, id)| id.map(|id| (LangItem::from_u32(i as u32).unwrap(), id))) |
| } |
| } |
| |
| // 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 { |
| ( |
| $( $(#[$attr:meta])* $variant:ident, $module:ident :: $name:ident, $method:ident, $target:expr, $generics:expr; )* |
| ) => { |
| |
| enum_from_u32! { |
| /// A representation of all the valid language items in Rust. |
| #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable)] |
| pub enum LangItem { |
| $( |
| #[doc = concat!("The `", stringify!($name), "` lang item.")] |
| /// |
| $(#[$attr])* |
| $variant, |
| )* |
| } |
| } |
| |
| impl LangItem { |
| /// Returns the `name` symbol in `#[lang = "$name"]`. |
| /// For example, [`LangItem::PartialEq`]`.name()` |
| /// would result in [`sym::eq`] since it is `#[lang = "eq"]`. |
| pub fn name(self) -> Symbol { |
| match self { |
| $( LangItem::$variant => $module::$name, )* |
| } |
| } |
| |
| /// Opposite of [`LangItem::name`] |
| pub fn from_name(name: Symbol) -> Option<Self> { |
| match name { |
| $( $module::$name => Some(LangItem::$variant), )* |
| _ => None, |
| } |
| } |
| |
| /// Returns the name of the `LangItem` enum variant. |
| // This method is used by Clippy for internal lints. |
| pub fn variant_name(self) -> &'static str { |
| match self { |
| $( LangItem::$variant => stringify!($variant), )* |
| } |
| } |
| |
| pub fn target(self) -> Target { |
| match self { |
| $( LangItem::$variant => $target, )* |
| } |
| } |
| |
| pub fn required_generics(&self) -> GenericRequirement { |
| match self { |
| $( LangItem::$variant => $generics, )* |
| } |
| } |
| } |
| |
| impl LanguageItems { |
| $( |
| #[doc = concat!("Returns the [`DefId`] of the `", stringify!($name), "` lang item if it is defined.")] |
| pub fn $method(&self) -> Option<DefId> { |
| self.items[LangItem::$variant as usize] |
| } |
| )* |
| } |
| } |
| } |
| |
| 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 `#[panic_handler]` attribute is also extracted out when found. |
| pub fn extract(attrs: &[ast::Attribute]) -> Option<(Symbol, Span)> { |
| attrs.iter().find_map(|attr| { |
| Some(match attr { |
| _ if attr.has_name(sym::lang) => (attr.value_str()?, attr.span), |
| _ if attr.has_name(sym::panic_handler) => (sym::panic_impl, attr.span), |
| _ => return None, |
| }) |
| }) |
| } |
| |
| language_item_table! { |
| // Variant name, Name, Getter method name, Target Generic requirements; |
| Sized, sym::sized, sized_trait, Target::Trait, GenericRequirement::Exact(0); |
| Unsize, sym::unsize, unsize_trait, Target::Trait, GenericRequirement::Minimum(1); |
| /// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ"). |
| StructuralPeq, sym::structural_peq, structural_peq_trait, Target::Trait, GenericRequirement::None; |
| /// Trait injected by `#[derive(Eq)]`, (i.e. "Total EQ"; no, I will not apologize). |
| StructuralTeq, sym::structural_teq, structural_teq_trait, Target::Trait, GenericRequirement::None; |
| Copy, sym::copy, copy_trait, Target::Trait, GenericRequirement::Exact(0); |
| Clone, sym::clone, clone_trait, Target::Trait, GenericRequirement::None; |
| Sync, sym::sync, sync_trait, Target::Trait, GenericRequirement::Exact(0); |
| DiscriminantKind, sym::discriminant_kind, discriminant_kind_trait, Target::Trait, GenericRequirement::None; |
| /// The associated item of the [`DiscriminantKind`] trait. |
| Discriminant, sym::discriminant_type, discriminant_type, Target::AssocTy, GenericRequirement::None; |
| |
| PointeeTrait, sym::pointee_trait, pointee_trait, Target::Trait, GenericRequirement::None; |
| Metadata, sym::metadata_type, metadata_type, Target::AssocTy, GenericRequirement::None; |
| DynMetadata, sym::dyn_metadata, dyn_metadata, Target::Struct, GenericRequirement::None; |
| |
| Freeze, sym::freeze, freeze_trait, Target::Trait, GenericRequirement::Exact(0); |
| |
| FnPtrTrait, sym::fn_ptr_trait, fn_ptr_trait, Target::Trait, GenericRequirement::Exact(0); |
| FnPtrAddr, sym::fn_ptr_addr, fn_ptr_addr, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| |
| Drop, sym::drop, drop_trait, Target::Trait, GenericRequirement::None; |
| Destruct, sym::destruct, destruct_trait, Target::Trait, GenericRequirement::None; |
| |
| CoerceUnsized, sym::coerce_unsized, coerce_unsized_trait, Target::Trait, GenericRequirement::Minimum(1); |
| DispatchFromDyn, sym::dispatch_from_dyn, dispatch_from_dyn_trait, Target::Trait, GenericRequirement::Minimum(1); |
| |
| // language items relating to transmutability |
| TransmuteOpts, sym::transmute_opts, transmute_opts, Target::Struct, GenericRequirement::Exact(0); |
| TransmuteTrait, sym::transmute_trait, transmute_trait, Target::Trait, GenericRequirement::Exact(3); |
| |
| Add, sym::add, add_trait, Target::Trait, GenericRequirement::Exact(1); |
| Sub, sym::sub, sub_trait, Target::Trait, GenericRequirement::Exact(1); |
| Mul, sym::mul, mul_trait, Target::Trait, GenericRequirement::Exact(1); |
| Div, sym::div, div_trait, Target::Trait, GenericRequirement::Exact(1); |
| Rem, sym::rem, rem_trait, Target::Trait, GenericRequirement::Exact(1); |
| Neg, sym::neg, neg_trait, Target::Trait, GenericRequirement::Exact(0); |
| Not, sym::not, not_trait, Target::Trait, GenericRequirement::Exact(0); |
| BitXor, sym::bitxor, bitxor_trait, Target::Trait, GenericRequirement::Exact(1); |
| BitAnd, sym::bitand, bitand_trait, Target::Trait, GenericRequirement::Exact(1); |
| BitOr, sym::bitor, bitor_trait, Target::Trait, GenericRequirement::Exact(1); |
| Shl, sym::shl, shl_trait, Target::Trait, GenericRequirement::Exact(1); |
| Shr, sym::shr, shr_trait, Target::Trait, GenericRequirement::Exact(1); |
| AddAssign, sym::add_assign, add_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| SubAssign, sym::sub_assign, sub_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| MulAssign, sym::mul_assign, mul_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| DivAssign, sym::div_assign, div_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| RemAssign, sym::rem_assign, rem_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| BitXorAssign, sym::bitxor_assign, bitxor_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| BitAndAssign, sym::bitand_assign, bitand_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| BitOrAssign, sym::bitor_assign, bitor_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| ShlAssign, sym::shl_assign, shl_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| ShrAssign, sym::shr_assign, shr_assign_trait, Target::Trait, GenericRequirement::Exact(1); |
| Index, sym::index, index_trait, Target::Trait, GenericRequirement::Exact(1); |
| IndexMut, sym::index_mut, index_mut_trait, Target::Trait, GenericRequirement::Exact(1); |
| |
| UnsafeCell, sym::unsafe_cell, unsafe_cell_type, Target::Struct, GenericRequirement::None; |
| VaList, sym::va_list, va_list, Target::Struct, GenericRequirement::None; |
| |
| Deref, sym::deref, deref_trait, Target::Trait, GenericRequirement::Exact(0); |
| DerefMut, sym::deref_mut, deref_mut_trait, Target::Trait, GenericRequirement::Exact(0); |
| DerefTarget, sym::deref_target, deref_target, Target::AssocTy, GenericRequirement::None; |
| Receiver, sym::receiver, receiver_trait, Target::Trait, GenericRequirement::None; |
| |
| Fn, kw::Fn, fn_trait, Target::Trait, GenericRequirement::Exact(1); |
| FnMut, sym::fn_mut, fn_mut_trait, Target::Trait, GenericRequirement::Exact(1); |
| FnOnce, sym::fn_once, fn_once_trait, Target::Trait, GenericRequirement::Exact(1); |
| |
| FnOnceOutput, sym::fn_once_output, fn_once_output, Target::AssocTy, GenericRequirement::None; |
| |
| Future, sym::future_trait, future_trait, Target::Trait, GenericRequirement::Exact(0); |
| GeneratorState, sym::generator_state, gen_state, Target::Enum, GenericRequirement::None; |
| Generator, sym::generator, gen_trait, Target::Trait, GenericRequirement::Minimum(1); |
| Unpin, sym::unpin, unpin_trait, Target::Trait, GenericRequirement::None; |
| Pin, sym::pin, pin_type, Target::Struct, GenericRequirement::None; |
| |
| PartialEq, sym::eq, eq_trait, Target::Trait, GenericRequirement::Exact(1); |
| PartialOrd, sym::partial_ord, partial_ord_trait, Target::Trait, GenericRequirement::Exact(1); |
| CVoid, sym::c_void, c_void, Target::Enum, GenericRequirement::None; |
| |
| // 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. |
| Panic, sym::panic, panic_fn, Target::Fn, GenericRequirement::Exact(0); |
| PanicNounwind, sym::panic_nounwind, panic_nounwind, Target::Fn, GenericRequirement::Exact(0); |
| PanicFmt, sym::panic_fmt, panic_fmt, Target::Fn, GenericRequirement::None; |
| PanicDisplay, sym::panic_display, panic_display, Target::Fn, GenericRequirement::None; |
| ConstPanicFmt, sym::const_panic_fmt, const_panic_fmt, Target::Fn, GenericRequirement::None; |
| PanicBoundsCheck, sym::panic_bounds_check, panic_bounds_check_fn, Target::Fn, GenericRequirement::Exact(0); |
| PanicMisalignedPointerDereference, sym::panic_misaligned_pointer_dereference, panic_misaligned_pointer_dereference_fn, Target::Fn, GenericRequirement::Exact(0); |
| PanicInfo, sym::panic_info, panic_info, Target::Struct, GenericRequirement::None; |
| PanicLocation, sym::panic_location, panic_location, Target::Struct, GenericRequirement::None; |
| PanicImpl, sym::panic_impl, panic_impl, Target::Fn, GenericRequirement::None; |
| PanicCannotUnwind, sym::panic_cannot_unwind, panic_cannot_unwind, Target::Fn, GenericRequirement::Exact(0); |
| /// libstd panic entry point. Necessary for const eval to be able to catch it |
| BeginPanic, sym::begin_panic, begin_panic_fn, Target::Fn, GenericRequirement::None; |
| |
| // Lang items needed for `format_args!()`. |
| FormatAlignment, sym::format_alignment, format_alignment, Target::Enum, GenericRequirement::None; |
| FormatArgument, sym::format_argument, format_argument, Target::Struct, GenericRequirement::None; |
| FormatArguments, sym::format_arguments, format_arguments, Target::Struct, GenericRequirement::None; |
| FormatCount, sym::format_count, format_count, Target::Enum, GenericRequirement::None; |
| FormatPlaceholder, sym::format_placeholder, format_placeholder, Target::Struct, GenericRequirement::None; |
| FormatUnsafeArg, sym::format_unsafe_arg, format_unsafe_arg, Target::Struct, GenericRequirement::None; |
| |
| ExchangeMalloc, sym::exchange_malloc, exchange_malloc_fn, Target::Fn, GenericRequirement::None; |
| BoxFree, sym::box_free, box_free_fn, Target::Fn, GenericRequirement::Minimum(1); |
| DropInPlace, sym::drop_in_place, drop_in_place_fn, Target::Fn, GenericRequirement::Minimum(1); |
| AllocLayout, sym::alloc_layout, alloc_layout, Target::Struct, GenericRequirement::None; |
| |
| Start, sym::start, start_fn, Target::Fn, GenericRequirement::Exact(1); |
| |
| EhPersonality, sym::eh_personality, eh_personality, Target::Fn, GenericRequirement::None; |
| EhCatchTypeinfo, sym::eh_catch_typeinfo, eh_catch_typeinfo, Target::Static, GenericRequirement::None; |
| |
| OwnedBox, sym::owned_box, owned_box, Target::Struct, GenericRequirement::Minimum(1); |
| |
| PhantomData, sym::phantom_data, phantom_data, Target::Struct, GenericRequirement::Exact(1); |
| |
| ManuallyDrop, sym::manually_drop, manually_drop, Target::Struct, GenericRequirement::None; |
| |
| MaybeUninit, sym::maybe_uninit, maybe_uninit, Target::Union, GenericRequirement::None; |
| |
| /// Align offset for stride != 1; must not panic. |
| AlignOffset, sym::align_offset, align_offset_fn, Target::Fn, GenericRequirement::None; |
| |
| Termination, sym::termination, termination, Target::Trait, GenericRequirement::None; |
| |
| Try, sym::Try, try_trait, Target::Trait, GenericRequirement::None; |
| |
| Tuple, sym::tuple_trait, tuple_trait, Target::Trait, GenericRequirement::Exact(0); |
| |
| SliceLen, sym::slice_len_fn, slice_len_fn, Target::Method(MethodKind::Inherent), GenericRequirement::None; |
| |
| // Language items from AST lowering |
| TryTraitFromResidual, sym::from_residual, from_residual_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| TryTraitFromOutput, sym::from_output, from_output_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| TryTraitBranch, sym::branch, branch_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| TryTraitFromYeet, sym::from_yeet, from_yeet_fn, Target::Fn, GenericRequirement::None; |
| |
| PointerLike, sym::pointer_like, pointer_like, Target::Trait, GenericRequirement::Exact(0); |
| |
| ConstParamTy, sym::const_param_ty, const_param_ty_trait, Target::Trait, GenericRequirement::Exact(0); |
| |
| Poll, sym::Poll, poll, Target::Enum, GenericRequirement::None; |
| PollReady, sym::Ready, poll_ready_variant, Target::Variant, GenericRequirement::None; |
| PollPending, sym::Pending, poll_pending_variant, Target::Variant, GenericRequirement::None; |
| |
| // FIXME(swatinem): the following lang items are used for async lowering and |
| // should become obsolete eventually. |
| ResumeTy, sym::ResumeTy, resume_ty, Target::Struct, GenericRequirement::None; |
| GetContext, sym::get_context, get_context_fn, Target::Fn, GenericRequirement::None; |
| |
| Context, sym::Context, context, Target::Struct, GenericRequirement::None; |
| FuturePoll, sym::poll, future_poll_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| |
| Option, sym::Option, option_type, Target::Enum, GenericRequirement::None; |
| OptionSome, sym::Some, option_some_variant, Target::Variant, GenericRequirement::None; |
| OptionNone, sym::None, option_none_variant, Target::Variant, GenericRequirement::None; |
| |
| ResultOk, sym::Ok, result_ok_variant, Target::Variant, GenericRequirement::None; |
| ResultErr, sym::Err, result_err_variant, Target::Variant, GenericRequirement::None; |
| |
| ControlFlowContinue, sym::Continue, cf_continue_variant, Target::Variant, GenericRequirement::None; |
| ControlFlowBreak, sym::Break, cf_break_variant, Target::Variant, GenericRequirement::None; |
| |
| IntoFutureIntoFuture, sym::into_future, into_future_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| IntoIterIntoIter, sym::into_iter, into_iter_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None; |
| IteratorNext, sym::next, next_fn, Target::Method(MethodKind::Trait { body: false}), GenericRequirement::None; |
| |
| PinNewUnchecked, sym::new_unchecked, new_unchecked_fn, Target::Method(MethodKind::Inherent), GenericRequirement::None; |
| |
| RangeFrom, sym::RangeFrom, range_from_struct, Target::Struct, GenericRequirement::None; |
| RangeFull, sym::RangeFull, range_full_struct, Target::Struct, GenericRequirement::None; |
| RangeInclusiveStruct, sym::RangeInclusive, range_inclusive_struct, Target::Struct, GenericRequirement::None; |
| RangeInclusiveNew, sym::range_inclusive_new, range_inclusive_new_method, Target::Method(MethodKind::Inherent), GenericRequirement::None; |
| Range, sym::Range, range_struct, Target::Struct, GenericRequirement::None; |
| RangeToInclusive, sym::RangeToInclusive, range_to_inclusive_struct, Target::Struct, GenericRequirement::None; |
| RangeTo, sym::RangeTo, range_to_struct, Target::Struct, GenericRequirement::None; |
| |
| String, sym::String, string, Target::Struct, GenericRequirement::None; |
| CStr, sym::CStr, c_str, Target::Struct, GenericRequirement::None; |
| } |
| |
| pub enum GenericRequirement { |
| None, |
| Minimum(usize), |
| Exact(usize), |
| } |
| |
| pub static FN_TRAITS: &'static [LangItem] = &[LangItem::Fn, LangItem::FnMut, LangItem::FnOnce]; |
| |
| pub static OPERATORS: &'static [LangItem] = &[ |
| LangItem::Add, |
| LangItem::Sub, |
| LangItem::Mul, |
| LangItem::Div, |
| LangItem::Rem, |
| LangItem::Neg, |
| LangItem::Not, |
| LangItem::BitXor, |
| LangItem::BitAnd, |
| LangItem::BitOr, |
| LangItem::Shl, |
| LangItem::Shr, |
| LangItem::AddAssign, |
| LangItem::SubAssign, |
| LangItem::MulAssign, |
| LangItem::DivAssign, |
| LangItem::RemAssign, |
| LangItem::BitXorAssign, |
| LangItem::BitAndAssign, |
| LangItem::BitOrAssign, |
| LangItem::ShlAssign, |
| LangItem::ShrAssign, |
| LangItem::Index, |
| LangItem::IndexMut, |
| LangItem::PartialEq, |
| LangItem::PartialOrd, |
| ]; |
