1 //! For each definition, we track the following data. A definition
2 //! here is defined somewhat circularly as "something with a `DefId`",
3 //! but it generally corresponds to things like structs, enums, etc.
4 //! There are also some rather random cases (like const initializer
5 //! expressions) that are mostly just leftovers.
7 pub use crate::def_id::DefPathHash;
8 use crate::def_id::{CrateNum, DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
11 use rustc_ast::crate_disambiguator::CrateDisambiguator;
12 use rustc_data_structures::fx::FxHashMap;
13 use rustc_data_structures::stable_hasher::StableHasher;
14 use rustc_index::vec::IndexVec;
15 use rustc_span::hygiene::ExpnId;
16 use rustc_span::symbol::{kw, sym, Symbol};
18 use std::fmt::{self, Write};
22 /// The `DefPathTable` maps `DefIndex`es to `DefKey`s and vice versa.
23 /// Internally the `DefPathTable` holds a tree of `DefKey`s, where each `DefKey`
24 /// stores the `DefIndex` of its parent.
25 /// There is one `DefPathTable` for each crate.
26 #[derive(Clone, Default)]
27 pub struct DefPathTable {
28 index_to_key: IndexVec<DefIndex, DefKey>,
29 def_path_hashes: IndexVec<DefIndex, DefPathHash>,
33 fn allocate(&mut self, key: DefKey, def_path_hash: DefPathHash) -> DefIndex {
35 let index = DefIndex::from(self.index_to_key.len());
36 debug!("DefPathTable::insert() - {:?} <-> {:?}", key, index);
37 self.index_to_key.push(key);
40 self.def_path_hashes.push(def_path_hash);
41 debug_assert!(self.def_path_hashes.len() == self.index_to_key.len());
46 pub fn def_key(&self, index: DefIndex) -> DefKey {
47 self.index_to_key[index]
51 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
52 let hash = self.def_path_hashes[index];
53 debug!("def_path_hash({:?}) = {:?}", index, hash);
57 pub fn num_def_ids(&self) -> usize {
58 self.index_to_key.len()
61 pub fn enumerated_keys_and_path_hashes(
63 ) -> impl Iterator<Item = (DefIndex, &DefKey, &DefPathHash)> + '_ {
66 .map(move |(index, key)| (index, key, &self.def_path_hashes[index]))
69 pub fn all_def_path_hashes_and_def_ids(
72 ) -> impl Iterator<Item = (DefPathHash, DefId)> + '_ {
75 .map(move |(index, hash)| (*hash, DefId { krate, index }))
79 /// The definition table containing node definitions.
80 /// It holds the `DefPathTable` for `LocalDefId`s/`DefPath`s.
81 /// It also stores mappings to convert `LocalDefId`s to/from `HirId`s.
83 pub struct Definitions {
86 // FIXME(eddyb) ideally all `LocalDefId`s would be HIR owners.
87 pub(super) def_id_to_hir_id: IndexVec<LocalDefId, Option<hir::HirId>>,
88 /// The reverse mapping of `def_id_to_hir_id`.
89 pub(super) hir_id_to_def_id: FxHashMap<hir::HirId, LocalDefId>,
91 /// If `ExpnId` is an ID of some macro expansion,
92 /// then `DefId` is the normal module (`mod`) in which the expanded macro was defined.
93 parent_modules_of_macro_defs: FxHashMap<ExpnId, DefId>,
94 /// Item with a given `LocalDefId` was defined during macro expansion with ID `ExpnId`.
95 expansions_that_defined: FxHashMap<LocalDefId, ExpnId>,
98 /// A unique identifier that we can use to lookup a definition
99 /// precisely. It combines the index of the definition's parent (if
100 /// any) with a `DisambiguatedDefPathData`.
101 #[derive(Copy, Clone, PartialEq, Debug, Encodable, Decodable)]
104 pub parent: Option<DefIndex>,
106 /// The identifier of this node.
107 pub disambiguated_data: DisambiguatedDefPathData,
111 fn compute_stable_hash(&self, parent_hash: DefPathHash) -> DefPathHash {
112 let mut hasher = StableHasher::new();
114 // We hash a `0u8` here to disambiguate between regular `DefPath` hashes,
115 // and the special "root_parent" below.
116 0u8.hash(&mut hasher);
117 parent_hash.hash(&mut hasher);
119 let DisambiguatedDefPathData { ref data, disambiguator } = self.disambiguated_data;
121 std::mem::discriminant(data).hash(&mut hasher);
122 if let Some(name) = data.get_opt_name() {
123 // Get a stable hash by considering the symbol chars rather than
125 name.as_str().hash(&mut hasher);
128 disambiguator.hash(&mut hasher);
130 DefPathHash(hasher.finish())
133 fn root_parent_stable_hash(
135 crate_disambiguator: CrateDisambiguator,
137 let mut hasher = StableHasher::new();
138 // Disambiguate this from a regular `DefPath` hash; see `compute_stable_hash()` above.
139 1u8.hash(&mut hasher);
140 crate_name.hash(&mut hasher);
141 crate_disambiguator.hash(&mut hasher);
142 DefPathHash(hasher.finish())
146 /// A pair of `DefPathData` and an integer disambiguator. The integer is
147 /// normally `0`, but in the event that there are multiple defs with the
148 /// same `parent` and `data`, we use this field to disambiguate
149 /// between them. This introduces some artificial ordering dependency
150 /// but means that if you have, e.g., two impls for the same type in
151 /// the same module, they do get distinct `DefId`s.
152 #[derive(Copy, Clone, PartialEq, Debug, Encodable, Decodable)]
153 pub struct DisambiguatedDefPathData {
154 pub data: DefPathData,
155 pub disambiguator: u32,
158 impl DisambiguatedDefPathData {
159 pub fn fmt_maybe_verbose(&self, writer: &mut impl Write, verbose: bool) -> fmt::Result {
160 match self.data.name() {
161 DefPathDataName::Named(name) => {
162 if verbose && self.disambiguator != 0 {
163 write!(writer, "{}#{}", name, self.disambiguator)
165 writer.write_str(&name.as_str())
168 DefPathDataName::Anon { namespace } => {
169 write!(writer, "{{{}#{}}}", namespace, self.disambiguator)
175 impl fmt::Display for DisambiguatedDefPathData {
176 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
177 self.fmt_maybe_verbose(f, true)
181 #[derive(Clone, Debug, Encodable, Decodable)]
183 /// The path leading from the crate root to the item.
184 pub data: Vec<DisambiguatedDefPathData>,
186 /// The crate root this path is relative to.
191 pub fn is_local(&self) -> bool {
192 self.krate == LOCAL_CRATE
195 pub fn make<FN>(krate: CrateNum, start_index: DefIndex, mut get_key: FN) -> DefPath
197 FN: FnMut(DefIndex) -> DefKey,
199 let mut data = vec![];
200 let mut index = Some(start_index);
202 debug!("DefPath::make: krate={:?} index={:?}", krate, index);
203 let p = index.unwrap();
204 let key = get_key(p);
205 debug!("DefPath::make: key={:?}", key);
206 match key.disambiguated_data.data {
207 DefPathData::CrateRoot => {
208 assert!(key.parent.is_none());
212 data.push(key.disambiguated_data);
218 DefPath { data, krate }
221 /// Returns a string representation of the `DefPath` without
222 /// the crate-prefix. This method is useful if you don't have
223 /// a `TyCtxt` available.
224 pub fn to_string_no_crate_verbose(&self) -> String {
225 let mut s = String::with_capacity(self.data.len() * 16);
227 for component in &self.data {
228 write!(s, "::{}", component).unwrap();
234 /// Returns a filename-friendly string of the `DefPath`, without
235 /// the crate-prefix. This method is useful if you don't have
236 /// a `TyCtxt` available.
237 pub fn to_filename_friendly_no_crate(&self) -> String {
238 let mut s = String::with_capacity(self.data.len() * 16);
240 let mut opt_delimiter = None;
241 for component in &self.data {
242 s.extend(opt_delimiter);
243 opt_delimiter = Some('-');
244 write!(s, "{}", component).unwrap();
251 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, Encodable, Decodable)]
252 pub enum DefPathData {
253 // Root: these should only be used for the root nodes, because
254 // they are treated specially by the `def_path` function.
255 /// The crate root (marker).
257 // Catch-all for random `DefId` things like `DUMMY_NODE_ID`.
260 // Different kinds of items and item-like things:
263 /// Something in the type namespace.
265 /// Something in the value namespace.
267 /// Something in the macro namespace.
269 /// Something in the lifetime namespace.
271 /// A closure expression.
274 // Subportions of items:
275 /// Implicit constructor for a unit or tuple-like struct or enum variant.
277 /// A constant expression (see `{ast,hir}::AnonConst`).
279 /// An `impl Trait` type node.
284 pub fn def_path_table(&self) -> &DefPathTable {
288 /// Gets the number of definitions.
289 pub fn def_index_count(&self) -> usize {
290 self.table.index_to_key.len()
293 pub fn def_key(&self, id: LocalDefId) -> DefKey {
294 self.table.def_key(id.local_def_index)
298 pub fn def_path_hash(&self, id: LocalDefId) -> DefPathHash {
299 self.table.def_path_hash(id.local_def_index)
302 /// Returns the path from the crate root to `index`. The root
303 /// nodes are not included in the path (i.e., this will be an
304 /// empty vector for the crate root). For an inlined item, this
305 /// will be the path of the item in the external crate (but the
306 /// path will begin with the path to the external crate).
307 pub fn def_path(&self, id: LocalDefId) -> DefPath {
308 DefPath::make(LOCAL_CRATE, id.local_def_index, |index| {
309 self.def_key(LocalDefId { local_def_index: index })
315 pub fn local_def_id_to_hir_id(&self, id: LocalDefId) -> hir::HirId {
316 self.def_id_to_hir_id[id].unwrap()
320 pub fn opt_local_def_id_to_hir_id(&self, id: LocalDefId) -> Option<hir::HirId> {
321 self.def_id_to_hir_id[id]
325 pub fn opt_hir_id_to_local_def_id(&self, hir_id: hir::HirId) -> Option<LocalDefId> {
326 self.hir_id_to_def_id.get(&hir_id).copied()
329 /// Adds a root definition (no parent) and a few other reserved definitions.
330 pub fn new(crate_name: &str, crate_disambiguator: CrateDisambiguator) -> Definitions {
333 disambiguated_data: DisambiguatedDefPathData {
334 data: DefPathData::CrateRoot,
339 let parent_hash = DefKey::root_parent_stable_hash(crate_name, crate_disambiguator);
340 let def_path_hash = key.compute_stable_hash(parent_hash);
342 // Create the root definition.
343 let mut table = DefPathTable::default();
344 let root = LocalDefId { local_def_index: table.allocate(key, def_path_hash) };
345 assert_eq!(root.local_def_index, CRATE_DEF_INDEX);
349 def_id_to_hir_id: Default::default(),
350 hir_id_to_def_id: Default::default(),
351 expansions_that_defined: Default::default(),
352 parent_modules_of_macro_defs: Default::default(),
356 /// Retrieves the root definition.
357 pub fn get_root_def(&self) -> LocalDefId {
358 LocalDefId { local_def_index: CRATE_DEF_INDEX }
361 /// Adds a definition with a parent definition.
367 mut next_disambiguator: impl FnMut(LocalDefId, DefPathData) -> u32,
369 debug!("create_def(parent={:?}, data={:?}, expn_id={:?})", parent, data, expn_id);
371 // The root node must be created with `create_root_def()`.
372 assert!(data != DefPathData::CrateRoot);
374 let disambiguator = next_disambiguator(parent, data);
376 parent: Some(parent.local_def_index),
377 disambiguated_data: DisambiguatedDefPathData { data, disambiguator },
380 let parent_hash = self.table.def_path_hash(parent.local_def_index);
381 let def_path_hash = key.compute_stable_hash(parent_hash);
383 debug!("create_def: after disambiguation, key = {:?}", key);
385 // Create the definition.
386 let def_id = LocalDefId { local_def_index: self.table.allocate(key, def_path_hash) };
388 if expn_id != ExpnId::root() {
389 self.expansions_that_defined.insert(def_id, expn_id);
395 /// Initializes the `LocalDefId` to `HirId` mapping once it has been generated during
396 /// AST to HIR lowering.
397 pub fn init_def_id_to_hir_id_mapping(
399 mapping: IndexVec<LocalDefId, Option<hir::HirId>>,
402 self.def_id_to_hir_id.is_empty(),
403 "trying to initialize `LocalDefId` <-> `HirId` mappings twice"
406 // Build the reverse mapping of `def_id_to_hir_id`.
407 self.hir_id_to_def_id = mapping
409 .filter_map(|(def_id, hir_id)| hir_id.map(|hir_id| (hir_id, def_id)))
412 self.def_id_to_hir_id = mapping;
415 pub fn expansion_that_defined(&self, id: LocalDefId) -> ExpnId {
416 self.expansions_that_defined.get(&id).copied().unwrap_or(ExpnId::root())
419 pub fn parent_module_of_macro_def(&self, expn_id: ExpnId) -> DefId {
420 self.parent_modules_of_macro_defs[&expn_id]
423 pub fn add_parent_module_of_macro_def(&mut self, expn_id: ExpnId, module: DefId) {
424 self.parent_modules_of_macro_defs.insert(expn_id, module);
428 #[derive(Copy, Clone, PartialEq, Debug)]
429 pub enum DefPathDataName {
431 Anon { namespace: Symbol },
435 pub fn get_opt_name(&self) -> Option<Symbol> {
436 use self::DefPathData::*;
438 TypeNs(name) | ValueNs(name) | MacroNs(name) | LifetimeNs(name) => Some(name),
440 Impl | CrateRoot | Misc | ClosureExpr | Ctor | AnonConst | ImplTrait => None,
444 pub fn name(&self) -> DefPathDataName {
445 use self::DefPathData::*;
447 TypeNs(name) | ValueNs(name) | MacroNs(name) | LifetimeNs(name) => {
448 DefPathDataName::Named(name)
450 // Note that this does not show up in user print-outs.
451 CrateRoot => DefPathDataName::Anon { namespace: kw::Crate },
452 Impl => DefPathDataName::Anon { namespace: kw::Impl },
453 Misc => DefPathDataName::Anon { namespace: sym::misc },
454 ClosureExpr => DefPathDataName::Anon { namespace: sym::closure },
455 Ctor => DefPathDataName::Anon { namespace: sym::constructor },
456 AnonConst => DefPathDataName::Anon { namespace: sym::constant },
457 ImplTrait => DefPathDataName::Anon { namespace: sym::opaque },
462 impl fmt::Display for DefPathData {
463 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
465 DefPathDataName::Named(name) => f.write_str(&name.as_str()),
466 // FIXME(#70334): this will generate legacy {{closure}}, {{impl}}, etc
467 DefPathDataName::Anon { namespace } => write!(f, "{{{{{}}}}}", namespace),