rustc_middle/hir/
mod.rs

1//! HIR datatypes. See the [rustc dev guide] for more info.
2//!
3//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/hir.html
4
5pub mod map;
6pub mod nested_filter;
7pub mod place;
8
9use rustc_data_structures::fingerprint::Fingerprint;
10use rustc_data_structures::sorted_map::SortedMap;
11use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
12use rustc_data_structures::sync::{DynSend, DynSync, try_par_for_each_in};
13use rustc_hir::def::{DefKind, Res};
14use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
15use rustc_hir::lints::DelayedLint;
16use rustc_hir::*;
17use rustc_macros::{Decodable, Encodable, HashStable};
18use rustc_span::{ErrorGuaranteed, ExpnId, Span};
19
20use crate::query::Providers;
21use crate::ty::TyCtxt;
22
23/// Gather the LocalDefId for each item-like within a module, including items contained within
24/// bodies. The Ids are in visitor order. This is used to partition a pass between modules.
25#[derive(Debug, HashStable, Encodable, Decodable)]
26pub struct ModuleItems {
27    /// Whether this represents the whole crate, in which case we need to add `CRATE_OWNER_ID` to
28    /// the iterators if we want to account for the crate root.
29    add_root: bool,
30    submodules: Box<[OwnerId]>,
31    free_items: Box<[ItemId]>,
32    trait_items: Box<[TraitItemId]>,
33    impl_items: Box<[ImplItemId]>,
34    foreign_items: Box<[ForeignItemId]>,
35    opaques: Box<[LocalDefId]>,
36    body_owners: Box<[LocalDefId]>,
37    nested_bodies: Box<[LocalDefId]>,
38    // only filled with hir_crate_items, not with hir_module_items
39    delayed_lint_items: Box<[OwnerId]>,
40}
41
42impl ModuleItems {
43    /// Returns all non-associated locally defined items in all modules.
44    ///
45    /// Note that this does *not* include associated items of `impl` blocks! It also does not
46    /// include foreign items. If you want to e.g. get all functions, use `definitions()` below.
47    ///
48    /// However, this does include the `impl` blocks themselves.
49    pub fn free_items(&self) -> impl Iterator<Item = ItemId> {
50        self.free_items.iter().copied()
51    }
52
53    pub fn trait_items(&self) -> impl Iterator<Item = TraitItemId> {
54        self.trait_items.iter().copied()
55    }
56
57    pub fn delayed_lint_items(&self) -> impl Iterator<Item = OwnerId> {
58        self.delayed_lint_items.iter().copied()
59    }
60
61    /// Returns all items that are associated with some `impl` block (both inherent and trait impl
62    /// blocks).
63    pub fn impl_items(&self) -> impl Iterator<Item = ImplItemId> {
64        self.impl_items.iter().copied()
65    }
66
67    pub fn foreign_items(&self) -> impl Iterator<Item = ForeignItemId> {
68        self.foreign_items.iter().copied()
69    }
70
71    pub fn owners(&self) -> impl Iterator<Item = OwnerId> {
72        self.add_root
73            .then_some(CRATE_OWNER_ID)
74            .into_iter()
75            .chain(self.free_items.iter().map(|id| id.owner_id))
76            .chain(self.trait_items.iter().map(|id| id.owner_id))
77            .chain(self.impl_items.iter().map(|id| id.owner_id))
78            .chain(self.foreign_items.iter().map(|id| id.owner_id))
79    }
80
81    pub fn opaques(&self) -> impl Iterator<Item = LocalDefId> {
82        self.opaques.iter().copied()
83    }
84
85    /// Closures and inline consts
86    pub fn nested_bodies(&self) -> impl Iterator<Item = LocalDefId> {
87        self.nested_bodies.iter().copied()
88    }
89
90    pub fn definitions(&self) -> impl Iterator<Item = LocalDefId> {
91        self.owners().map(|id| id.def_id)
92    }
93
94    /// Closures and inline consts
95    pub fn par_nested_bodies(
96        &self,
97        f: impl Fn(LocalDefId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
98    ) -> Result<(), ErrorGuaranteed> {
99        try_par_for_each_in(&self.nested_bodies[..], |&&id| f(id))
100    }
101
102    pub fn par_items(
103        &self,
104        f: impl Fn(ItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
105    ) -> Result<(), ErrorGuaranteed> {
106        try_par_for_each_in(&self.free_items[..], |&&id| f(id))
107    }
108
109    pub fn par_trait_items(
110        &self,
111        f: impl Fn(TraitItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
112    ) -> Result<(), ErrorGuaranteed> {
113        try_par_for_each_in(&self.trait_items[..], |&&id| f(id))
114    }
115
116    pub fn par_impl_items(
117        &self,
118        f: impl Fn(ImplItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
119    ) -> Result<(), ErrorGuaranteed> {
120        try_par_for_each_in(&self.impl_items[..], |&&id| f(id))
121    }
122
123    pub fn par_foreign_items(
124        &self,
125        f: impl Fn(ForeignItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
126    ) -> Result<(), ErrorGuaranteed> {
127        try_par_for_each_in(&self.foreign_items[..], |&&id| f(id))
128    }
129
130    pub fn par_opaques(
131        &self,
132        f: impl Fn(LocalDefId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
133    ) -> Result<(), ErrorGuaranteed> {
134        try_par_for_each_in(&self.opaques[..], |&&id| f(id))
135    }
136}
137
138impl<'tcx> TyCtxt<'tcx> {
139    pub fn parent_module(self, id: HirId) -> LocalModDefId {
140        if !id.is_owner() && self.def_kind(id.owner) == DefKind::Mod {
141            LocalModDefId::new_unchecked(id.owner.def_id)
142        } else {
143            self.parent_module_from_def_id(id.owner.def_id)
144        }
145    }
146
147    pub fn parent_module_from_def_id(self, mut id: LocalDefId) -> LocalModDefId {
148        while let Some(parent) = self.opt_local_parent(id) {
149            id = parent;
150            if self.def_kind(id) == DefKind::Mod {
151                break;
152            }
153        }
154        LocalModDefId::new_unchecked(id)
155    }
156
157    /// Returns `true` if this is a foreign item (i.e., linked via `extern { ... }`).
158    pub fn is_foreign_item(self, def_id: impl Into<DefId>) -> bool {
159        self.opt_parent(def_id.into())
160            .is_some_and(|parent| matches!(self.def_kind(parent), DefKind::ForeignMod))
161    }
162
163    pub fn hash_owner_nodes(
164        self,
165        node: OwnerNode<'_>,
166        bodies: &SortedMap<ItemLocalId, &Body<'_>>,
167        attrs: &SortedMap<ItemLocalId, &[Attribute]>,
168        delayed_lints: &[DelayedLint],
169        define_opaque: Option<&[(Span, LocalDefId)]>,
170    ) -> Hashes {
171        if !self.needs_crate_hash() {
172            return Hashes {
173                opt_hash_including_bodies: None,
174                attrs_hash: None,
175                delayed_lints_hash: None,
176            };
177        }
178
179        self.with_stable_hashing_context(|mut hcx| {
180            let mut stable_hasher = StableHasher::new();
181            node.hash_stable(&mut hcx, &mut stable_hasher);
182            // Bodies are stored out of line, so we need to pull them explicitly in the hash.
183            bodies.hash_stable(&mut hcx, &mut stable_hasher);
184            let h1 = stable_hasher.finish();
185
186            let mut stable_hasher = StableHasher::new();
187            attrs.hash_stable(&mut hcx, &mut stable_hasher);
188
189            // Hash the defined opaque types, which are not present in the attrs.
190            define_opaque.hash_stable(&mut hcx, &mut stable_hasher);
191
192            let h2 = stable_hasher.finish();
193
194            // hash lints emitted during ast lowering
195            let mut stable_hasher = StableHasher::new();
196            delayed_lints.hash_stable(&mut hcx, &mut stable_hasher);
197            let h3 = stable_hasher.finish();
198
199            Hashes {
200                opt_hash_including_bodies: Some(h1),
201                attrs_hash: Some(h2),
202                delayed_lints_hash: Some(h3),
203            }
204        })
205    }
206
207    pub fn qpath_is_lang_item(self, qpath: QPath<'_>, lang_item: LangItem) -> bool {
208        self.qpath_lang_item(qpath) == Some(lang_item)
209    }
210
211    /// This does not use typeck results since this is intended to be used with generated code.
212    pub fn qpath_lang_item(self, qpath: QPath<'_>) -> Option<LangItem> {
213        if let QPath::Resolved(_, path) = qpath
214            && let Res::Def(_, def_id) = path.res
215        {
216            return self.lang_items().from_def_id(def_id);
217        }
218        None
219    }
220
221    /// Whether this expression constitutes a read of value of the type that
222    /// it evaluates to.
223    ///
224    /// This is used to determine if we should consider the block to diverge
225    /// if the expression evaluates to `!`, and if we should insert a `NeverToAny`
226    /// coercion for values of type `!`.
227    ///
228    /// This function generally returns `false` if the expression is a place
229    /// expression and the *parent* expression is the scrutinee of a match or
230    /// the pointee of an `&` addr-of expression, since both of those parent
231    /// expressions take a *place* and not a value.
232    pub fn expr_guaranteed_to_constitute_read_for_never(self, expr: &Expr<'_>) -> bool {
233        // We only care about place exprs. Anything else returns an immediate
234        // which would constitute a read. We don't care about distinguishing
235        // "syntactic" place exprs since if the base of a field projection is
236        // not a place then it would've been UB to read from it anyways since
237        // that constitutes a read.
238        if !expr.is_syntactic_place_expr() {
239            return true;
240        }
241
242        let parent_node = self.parent_hir_node(expr.hir_id);
243        match parent_node {
244            Node::Expr(parent_expr) => {
245                match parent_expr.kind {
246                    // Addr-of, field projections, and LHS of assignment don't constitute reads.
247                    // Assignment does call `drop_in_place`, though, but its safety
248                    // requirements are not the same.
249                    ExprKind::AddrOf(..) | ExprKind::Field(..) => false,
250
251                    // Place-preserving expressions only constitute reads if their
252                    // parent expression constitutes a read.
253                    ExprKind::Type(..) | ExprKind::UnsafeBinderCast(..) => {
254                        self.expr_guaranteed_to_constitute_read_for_never(parent_expr)
255                    }
256
257                    ExprKind::Assign(lhs, _, _) => {
258                        // Only the LHS does not constitute a read
259                        expr.hir_id != lhs.hir_id
260                    }
261
262                    // See note on `PatKind::Or` in `Pat::is_guaranteed_to_constitute_read_for_never`
263                    // for why this is `all`.
264                    ExprKind::Match(scrutinee, arms, _) => {
265                        assert_eq!(scrutinee.hir_id, expr.hir_id);
266                        arms.iter().all(|arm| arm.pat.is_guaranteed_to_constitute_read_for_never())
267                    }
268                    ExprKind::Let(LetExpr { init, pat, .. }) => {
269                        assert_eq!(init.hir_id, expr.hir_id);
270                        pat.is_guaranteed_to_constitute_read_for_never()
271                    }
272
273                    // Any expression child of these expressions constitute reads.
274                    ExprKind::Array(_)
275                    | ExprKind::Call(_, _)
276                    | ExprKind::Use(_, _)
277                    | ExprKind::MethodCall(_, _, _, _)
278                    | ExprKind::Tup(_)
279                    | ExprKind::Binary(_, _, _)
280                    | ExprKind::Unary(_, _)
281                    | ExprKind::Cast(_, _)
282                    | ExprKind::DropTemps(_)
283                    | ExprKind::If(_, _, _)
284                    | ExprKind::Closure(_)
285                    | ExprKind::Block(_, _)
286                    | ExprKind::AssignOp(_, _, _)
287                    | ExprKind::Index(_, _, _)
288                    | ExprKind::Break(_, _)
289                    | ExprKind::Ret(_)
290                    | ExprKind::Become(_)
291                    | ExprKind::InlineAsm(_)
292                    | ExprKind::Struct(_, _, _)
293                    | ExprKind::Repeat(_, _)
294                    | ExprKind::Yield(_, _) => true,
295
296                    // These expressions have no (direct) sub-exprs.
297                    ExprKind::ConstBlock(_)
298                    | ExprKind::Loop(_, _, _, _)
299                    | ExprKind::Lit(_)
300                    | ExprKind::Path(_)
301                    | ExprKind::Continue(_)
302                    | ExprKind::OffsetOf(_, _)
303                    | ExprKind::Err(_) => unreachable!("no sub-expr expected for {:?}", expr.kind),
304                }
305            }
306
307            // If we have a subpattern that performs a read, we want to consider this
308            // to diverge for compatibility to support something like `let x: () = *never_ptr;`.
309            Node::LetStmt(LetStmt { init: Some(target), pat, .. }) => {
310                assert_eq!(target.hir_id, expr.hir_id);
311                pat.is_guaranteed_to_constitute_read_for_never()
312            }
313
314            // These nodes (if they have a sub-expr) do constitute a read.
315            Node::Block(_)
316            | Node::Arm(_)
317            | Node::ExprField(_)
318            | Node::AnonConst(_)
319            | Node::ConstBlock(_)
320            | Node::ConstArg(_)
321            | Node::Stmt(_)
322            | Node::Item(Item { kind: ItemKind::Const(..) | ItemKind::Static(..), .. })
323            | Node::TraitItem(TraitItem { kind: TraitItemKind::Const(..), .. })
324            | Node::ImplItem(ImplItem { kind: ImplItemKind::Const(..), .. }) => true,
325
326            Node::TyPat(_) | Node::Pat(_) => {
327                self.dcx().span_delayed_bug(expr.span, "place expr not allowed in pattern");
328                true
329            }
330
331            // These nodes do not have direct sub-exprs.
332            Node::Param(_)
333            | Node::Item(_)
334            | Node::ForeignItem(_)
335            | Node::TraitItem(_)
336            | Node::ImplItem(_)
337            | Node::Variant(_)
338            | Node::Field(_)
339            | Node::PathSegment(_)
340            | Node::Ty(_)
341            | Node::AssocItemConstraint(_)
342            | Node::TraitRef(_)
343            | Node::PatField(_)
344            | Node::PatExpr(_)
345            | Node::LetStmt(_)
346            | Node::Synthetic
347            | Node::Err(_)
348            | Node::Ctor(_)
349            | Node::Lifetime(_)
350            | Node::GenericParam(_)
351            | Node::Crate(_)
352            | Node::Infer(_)
353            | Node::WherePredicate(_)
354            | Node::PreciseCapturingNonLifetimeArg(_)
355            | Node::OpaqueTy(_) => {
356                unreachable!("no sub-expr expected for {parent_node:?}")
357            }
358        }
359    }
360}
361
362/// Hashes computed by [`TyCtxt::hash_owner_nodes`] if necessary.
363#[derive(Clone, Copy, Debug)]
364pub struct Hashes {
365    pub opt_hash_including_bodies: Option<Fingerprint>,
366    pub attrs_hash: Option<Fingerprint>,
367    pub delayed_lints_hash: Option<Fingerprint>,
368}
369
370pub fn provide(providers: &mut Providers) {
371    providers.hir_crate_items = map::hir_crate_items;
372    providers.crate_hash = map::crate_hash;
373    providers.hir_module_items = map::hir_module_items;
374    providers.local_def_id_to_hir_id = |tcx, def_id| match tcx.hir_crate(()).owners[def_id] {
375        MaybeOwner::Owner(_) => HirId::make_owner(def_id),
376        MaybeOwner::NonOwner(hir_id) => hir_id,
377        MaybeOwner::Phantom => bug!("No HirId for {:?}", def_id),
378    };
379    providers.opt_hir_owner_nodes =
380        |tcx, id| tcx.hir_crate(()).owners.get(id)?.as_owner().map(|i| &i.nodes);
381    providers.hir_owner_parent = |tcx, owner_id| {
382        tcx.opt_local_parent(owner_id.def_id).map_or(CRATE_HIR_ID, |parent_def_id| {
383            let parent_owner_id = tcx.local_def_id_to_hir_id(parent_def_id).owner;
384            HirId {
385                owner: parent_owner_id,
386                local_id: tcx.hir_crate(()).owners[parent_owner_id.def_id]
387                    .unwrap()
388                    .parenting
389                    .get(&owner_id.def_id)
390                    .copied()
391                    .unwrap_or(ItemLocalId::ZERO),
392            }
393        })
394    };
395    providers.hir_attr_map = |tcx, id| {
396        tcx.hir_crate(()).owners[id.def_id].as_owner().map_or(AttributeMap::EMPTY, |o| &o.attrs)
397    };
398    providers.opt_ast_lowering_delayed_lints =
399        |tcx, id| tcx.hir_crate(()).owners[id.def_id].as_owner().map(|o| &o.delayed_lints);
400    providers.def_span = |tcx, def_id| tcx.hir_span(tcx.local_def_id_to_hir_id(def_id));
401    providers.def_ident_span = |tcx, def_id| {
402        let hir_id = tcx.local_def_id_to_hir_id(def_id);
403        tcx.hir_opt_ident_span(hir_id)
404    };
405    providers.ty_span = |tcx, def_id| {
406        let node = tcx.hir_node_by_def_id(def_id);
407        match node.ty() {
408            Some(ty) => ty.span,
409            None => bug!("{def_id:?} doesn't have a type: {node:#?}"),
410        }
411    };
412    providers.fn_arg_idents = |tcx, def_id| {
413        let node = tcx.hir_node_by_def_id(def_id);
414        if let Some(body_id) = node.body_id() {
415            tcx.arena.alloc_from_iter(tcx.hir_body_param_idents(body_id))
416        } else if let Node::TraitItem(&TraitItem {
417            kind: TraitItemKind::Fn(_, TraitFn::Required(idents)),
418            ..
419        })
420        | Node::ForeignItem(&ForeignItem {
421            kind: ForeignItemKind::Fn(_, idents, _),
422            ..
423        }) = node
424        {
425            idents
426        } else {
427            span_bug!(
428                tcx.hir_span(tcx.local_def_id_to_hir_id(def_id)),
429                "fn_arg_idents: unexpected item {:?}",
430                def_id
431            );
432        }
433    };
434    providers.all_local_trait_impls = |tcx, ()| &tcx.resolutions(()).trait_impls;
435    providers.local_trait_impls =
436        |tcx, trait_id| tcx.resolutions(()).trait_impls.get(&trait_id).map_or(&[], |xs| &xs[..]);
437    providers.expn_that_defined =
438        |tcx, id| tcx.resolutions(()).expn_that_defined.get(&id).copied().unwrap_or(ExpnId::root());
439    providers.in_scope_traits_map = |tcx, id| {
440        tcx.hir_crate(()).owners[id.def_id].as_owner().map(|owner_info| &owner_info.trait_map)
441    };
442}
rustc_middle/hir/mod.rs

rustc_middle/hir/
mod.rs
