compiler/rustc_ast_lowering/src/index.rs

   1 use rustc_data_structures::fx::FxHashMap;
   2 use rustc_data_structures::sorted_map::SortedMap;
   3 use rustc_hir as hir;
   4 use rustc_hir::def_id::LocalDefId;
   5 use rustc_hir::definitions;
   6 use rustc_hir::intravisit::{self, Visitor};
   7 use rustc_hir::*;
   8 use rustc_index::vec::{Idx, IndexVec};
   9 use rustc_middle::span_bug;
  10 use rustc_session::Session;
  11 use rustc_span::source_map::SourceMap;
  12 use rustc_span::{Span, DUMMY_SP};
  13
  14 use tracing::debug;
  15
  16 /// A visitor that walks over the HIR and collects `Node`s into a HIR map.
  17 pub(super) struct NodeCollector<'a, 'hir> {
  18     /// Source map
  19     source_map: &'a SourceMap,
  20     bodies: &'a SortedMap<ItemLocalId, &'hir Body<'hir>>,
  21
  22     /// Outputs
  23     nodes: IndexVec<ItemLocalId, Option<ParentedNode<'hir>>>,
  24     parenting: FxHashMap<LocalDefId, ItemLocalId>,
  25
  26     /// The parent of this node
  27     parent_node: hir::ItemLocalId,
  28
  29     owner: LocalDefId,
  30
  31     definitions: &'a definitions::Definitions,
  32 }
  33
  34 #[tracing::instrument(level = "debug", skip(sess, definitions, bodies))]
  35 pub(super) fn index_hir<'hir>(
  36     sess: &Session,
  37     definitions: &definitions::Definitions,
  38     item: hir::OwnerNode<'hir>,
  39     bodies: &SortedMap<ItemLocalId, &'hir Body<'hir>>,
  40 ) -> (IndexVec<ItemLocalId, Option<ParentedNode<'hir>>>, FxHashMap<LocalDefId, ItemLocalId>) {
  41     let mut nodes = IndexVec::new();
  42     // This node's parent should never be accessed: the owner's parent is computed by the
  43     // hir_owner_parent query.  Make it invalid (= ItemLocalId::MAX) to force an ICE whenever it is
  44     // used.
  45     nodes.push(Some(ParentedNode { parent: ItemLocalId::INVALID, node: item.into() }));
  46     let mut collector = NodeCollector {
  47         source_map: sess.source_map(),
  48         definitions,
  49         owner: item.def_id(),
  50         parent_node: ItemLocalId::new(0),
  51         nodes,
  52         bodies,
  53         parenting: FxHashMap::default(),
  54     };
  55
  56     match item {
  57         OwnerNode::Crate(citem) => {
  58             collector.visit_mod(&citem, citem.spans.inner_span, hir::CRATE_HIR_ID)
  59         }
  60         OwnerNode::Item(item) => collector.visit_item(item),
  61         OwnerNode::TraitItem(item) => collector.visit_trait_item(item),
  62         OwnerNode::ImplItem(item) => collector.visit_impl_item(item),
  63         OwnerNode::ForeignItem(item) => collector.visit_foreign_item(item),
  64     };
  65
  66     (collector.nodes, collector.parenting)
  67 }
  68
  69 impl<'a, 'hir> NodeCollector<'a, 'hir> {
  70     #[tracing::instrument(level = "debug", skip(self))]
  71     fn insert(&mut self, span: Span, hir_id: HirId, node: Node<'hir>) {
  72         debug_assert_eq!(self.owner, hir_id.owner);
  73         debug_assert_ne!(hir_id.local_id.as_u32(), 0);
  74
  75         // Make sure that the DepNode of some node coincides with the HirId
  76         // owner of that node.
  77         if cfg!(debug_assertions) {
  78             if hir_id.owner != self.owner {
  79                 span_bug!(
  80                     span,
  81                     "inconsistent DepNode at `{:?}` for `{:?}`: \
  82                      current_dep_node_owner={} ({:?}), hir_id.owner={} ({:?})",
  83                     self.source_map.span_to_diagnostic_string(span),
  84                     node,
  85                     self.definitions.def_path(self.owner).to_string_no_crate_verbose(),
  86                     self.owner,
  87                     self.definitions.def_path(hir_id.owner).to_string_no_crate_verbose(),
  88                     hir_id.owner,
  89                 )
  90             }
  91         }
  92
  93         self.nodes.insert(hir_id.local_id, ParentedNode { parent: self.parent_node, node: node });
  94     }
  95
  96     fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_node_id: HirId, f: F) {
  97         debug_assert_eq!(parent_node_id.owner, self.owner);
  98         let parent_node = self.parent_node;
  99         self.parent_node = parent_node_id.local_id;
 100         f(self);
 101         self.parent_node = parent_node;
 102     }
 103
 104     fn insert_nested(&mut self, item: LocalDefId) {
 105         self.parenting.insert(item, self.parent_node);
 106     }
 107 }
 108
 109 impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
 110     /// Because we want to track parent items and so forth, enable
 111     /// deep walking so that we walk nested items in the context of
 112     /// their outer items.
 113
 114     fn visit_nested_item(&mut self, item: ItemId) {
 115         debug!("visit_nested_item: {:?}", item);
 116         self.insert_nested(item.def_id);
 117     }
 118
 119     fn visit_nested_trait_item(&mut self, item_id: TraitItemId) {
 120         self.insert_nested(item_id.def_id);
 121     }
 122
 123     fn visit_nested_impl_item(&mut self, item_id: ImplItemId) {
 124         self.insert_nested(item_id.def_id);
 125     }
 126
 127     fn visit_nested_foreign_item(&mut self, foreign_id: ForeignItemId) {
 128         self.insert_nested(foreign_id.def_id);
 129     }
 130
 131     fn visit_nested_body(&mut self, id: BodyId) {
 132         debug_assert_eq!(id.hir_id.owner, self.owner);
 133         let body = self.bodies[&id.hir_id.local_id];
 134         self.visit_body(body);
 135     }
 136
 137     fn visit_param(&mut self, param: &'hir Param<'hir>) {
 138         let node = Node::Param(param);
 139         self.insert(param.pat.span, param.hir_id, node);
 140         self.with_parent(param.hir_id, |this| {
 141             intravisit::walk_param(this, param);
 142         });
 143     }
 144
 145     #[tracing::instrument(level = "debug", skip(self))]
 146     fn visit_item(&mut self, i: &'hir Item<'hir>) {
 147         debug_assert_eq!(i.def_id, self.owner);
 148         self.with_parent(i.hir_id(), |this| {
 149             if let ItemKind::Struct(ref struct_def, _) = i.kind {
 150                 // If this is a tuple or unit-like struct, register the constructor.
 151                 if let Some(ctor_hir_id) = struct_def.ctor_hir_id() {
 152                     this.insert(i.span, ctor_hir_id, Node::Ctor(struct_def));
 153                 }
 154             }
 155             intravisit::walk_item(this, i);
 156         });
 157     }
 158
 159     #[tracing::instrument(level = "debug", skip(self))]
 160     fn visit_foreign_item(&mut self, fi: &'hir ForeignItem<'hir>) {
 161         debug_assert_eq!(fi.def_id, self.owner);
 162         self.with_parent(fi.hir_id(), |this| {
 163             intravisit::walk_foreign_item(this, fi);
 164         });
 165     }
 166
 167     fn visit_generic_param(&mut self, param: &'hir GenericParam<'hir>) {
 168         self.insert(param.span, param.hir_id, Node::GenericParam(param));
 169         intravisit::walk_generic_param(self, param);
 170     }
 171
 172     fn visit_const_param_default(&mut self, param: HirId, ct: &'hir AnonConst) {
 173         self.with_parent(param, |this| {
 174             intravisit::walk_const_param_default(this, ct);
 175         })
 176     }
 177
 178     #[tracing::instrument(level = "debug", skip(self))]
 179     fn visit_trait_item(&mut self, ti: &'hir TraitItem<'hir>) {
 180         debug_assert_eq!(ti.def_id, self.owner);
 181         self.with_parent(ti.hir_id(), |this| {
 182             intravisit::walk_trait_item(this, ti);
 183         });
 184     }
 185
 186     #[tracing::instrument(level = "debug", skip(self))]
 187     fn visit_impl_item(&mut self, ii: &'hir ImplItem<'hir>) {
 188         debug_assert_eq!(ii.def_id, self.owner);
 189         self.with_parent(ii.hir_id(), |this| {
 190             intravisit::walk_impl_item(this, ii);
 191         });
 192     }
 193
 194     fn visit_pat(&mut self, pat: &'hir Pat<'hir>) {
 195         let node =
 196             if let PatKind::Binding(..) = pat.kind { Node::Binding(pat) } else { Node::Pat(pat) };
 197         self.insert(pat.span, pat.hir_id, node);
 198
 199         self.with_parent(pat.hir_id, |this| {
 200             intravisit::walk_pat(this, pat);
 201         });
 202     }
 203
 204     fn visit_arm(&mut self, arm: &'hir Arm<'hir>) {
 205         let node = Node::Arm(arm);
 206
 207         self.insert(arm.span, arm.hir_id, node);
 208
 209         self.with_parent(arm.hir_id, |this| {
 210             intravisit::walk_arm(this, arm);
 211         });
 212     }
 213
 214     fn visit_anon_const(&mut self, constant: &'hir AnonConst) {
 215         self.insert(DUMMY_SP, constant.hir_id, Node::AnonConst(constant));
 216
 217         self.with_parent(constant.hir_id, |this| {
 218             intravisit::walk_anon_const(this, constant);
 219         });
 220     }
 221
 222     fn visit_expr(&mut self, expr: &'hir Expr<'hir>) {
 223         self.insert(expr.span, expr.hir_id, Node::Expr(expr));
 224
 225         self.with_parent(expr.hir_id, |this| {
 226             intravisit::walk_expr(this, expr);
 227         });
 228     }
 229
 230     fn visit_stmt(&mut self, stmt: &'hir Stmt<'hir>) {
 231         self.insert(stmt.span, stmt.hir_id, Node::Stmt(stmt));
 232
 233         self.with_parent(stmt.hir_id, |this| {
 234             intravisit::walk_stmt(this, stmt);
 235         });
 236     }
 237
 238     fn visit_path_segment(&mut self, path_span: Span, path_segment: &'hir PathSegment<'hir>) {
 239         if let Some(hir_id) = path_segment.hir_id {
 240             self.insert(path_span, hir_id, Node::PathSegment(path_segment));
 241         }
 242         intravisit::walk_path_segment(self, path_span, path_segment);
 243     }
 244
 245     fn visit_ty(&mut self, ty: &'hir Ty<'hir>) {
 246         self.insert(ty.span, ty.hir_id, Node::Ty(ty));
 247
 248         self.with_parent(ty.hir_id, |this| {
 249             intravisit::walk_ty(this, ty);
 250         });
 251     }
 252
 253     fn visit_infer(&mut self, inf: &'hir InferArg) {
 254         self.insert(inf.span, inf.hir_id, Node::Infer(inf));
 255
 256         self.with_parent(inf.hir_id, |this| {
 257             intravisit::walk_inf(this, inf);
 258         });
 259     }
 260
 261     fn visit_trait_ref(&mut self, tr: &'hir TraitRef<'hir>) {
 262         self.insert(tr.path.span, tr.hir_ref_id, Node::TraitRef(tr));
 263
 264         self.with_parent(tr.hir_ref_id, |this| {
 265             intravisit::walk_trait_ref(this, tr);
 266         });
 267     }
 268
 269     fn visit_fn(
 270         &mut self,
 271         fk: intravisit::FnKind<'hir>,
 272         fd: &'hir FnDecl<'hir>,
 273         b: BodyId,
 274         s: Span,
 275         id: HirId,
 276     ) {
 277         assert_eq!(self.owner, id.owner);
 278         assert_eq!(self.parent_node, id.local_id);
 279         intravisit::walk_fn(self, fk, fd, b, s, id);
 280     }
 281
 282     fn visit_block(&mut self, block: &'hir Block<'hir>) {
 283         self.insert(block.span, block.hir_id, Node::Block(block));
 284         self.with_parent(block.hir_id, |this| {
 285             intravisit::walk_block(this, block);
 286         });
 287     }
 288
 289     fn visit_local(&mut self, l: &'hir Local<'hir>) {
 290         self.insert(l.span, l.hir_id, Node::Local(l));
 291         self.with_parent(l.hir_id, |this| {
 292             intravisit::walk_local(this, l);
 293         })
 294     }
 295
 296     fn visit_lifetime(&mut self, lifetime: &'hir Lifetime) {
 297         self.insert(lifetime.span, lifetime.hir_id, Node::Lifetime(lifetime));
 298     }
 299
 300     fn visit_variant(&mut self, v: &'hir Variant<'hir>, g: &'hir Generics<'hir>, item_id: HirId) {
 301         self.insert(v.span, v.id, Node::Variant(v));
 302         self.with_parent(v.id, |this| {
 303             // Register the constructor of this variant.
 304             if let Some(ctor_hir_id) = v.data.ctor_hir_id() {
 305                 this.insert(v.span, ctor_hir_id, Node::Ctor(&v.data));
 306             }
 307             intravisit::walk_variant(this, v, g, item_id);
 308         });
 309     }
 310
 311     fn visit_field_def(&mut self, field: &'hir FieldDef<'hir>) {
 312         self.insert(field.span, field.hir_id, Node::Field(field));
 313         self.with_parent(field.hir_id, |this| {
 314             intravisit::walk_field_def(this, field);
 315         });
 316     }
 317
 318     fn visit_assoc_type_binding(&mut self, type_binding: &'hir TypeBinding<'hir>) {
 319         self.insert(type_binding.span, type_binding.hir_id, Node::TypeBinding(type_binding));
 320         self.with_parent(type_binding.hir_id, |this| {
 321             intravisit::walk_assoc_type_binding(this, type_binding)
 322         })
 323     }
 324
 325     fn visit_trait_item_ref(&mut self, ii: &'hir TraitItemRef) {
 326         // Do not visit the duplicate information in TraitItemRef. We want to
 327         // map the actual nodes, not the duplicate ones in the *Ref.
 328         let TraitItemRef { id, ident: _, kind: _, span: _, defaultness: _ } = *ii;
 329
 330         self.visit_nested_trait_item(id);
 331     }
 332
 333     fn visit_impl_item_ref(&mut self, ii: &'hir ImplItemRef) {
 334         // Do not visit the duplicate information in ImplItemRef. We want to
 335         // map the actual nodes, not the duplicate ones in the *Ref.
 336         let ImplItemRef { id, ident: _, kind: _, span: _, defaultness: _, trait_item_def_id: _ } =
 337             *ii;
 338
 339         self.visit_nested_impl_item(id);
 340     }
 341
 342     fn visit_foreign_item_ref(&mut self, fi: &'hir ForeignItemRef) {
 343         // Do not visit the duplicate information in ForeignItemRef. We want to
 344         // map the actual nodes, not the duplicate ones in the *Ref.
 345         let ForeignItemRef { id, ident: _, span: _ } = *fi;
 346
 347         self.visit_nested_foreign_item(id);
 348     }
 349 }