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.
8 use crate::hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE, CRATE_DEF_INDEX};
9 use crate::ich::Fingerprint;
10 use crate::session::CrateDisambiguator;
11 use crate::util::nodemap::NodeMap;
13 use rustc_data_structures::fx::FxHashMap;
14 use rustc_index::vec::{IndexVec};
15 use rustc_data_structures::stable_hasher::StableHasher;
16 use std::borrow::Borrow;
20 use syntax_pos::symbol::{Symbol, sym};
21 use syntax_pos::hygiene::ExpnId;
24 /// The `DefPathTable` maps `DefIndex`es to `DefKey`s and vice versa.
25 /// Internally the `DefPathTable` holds a tree of `DefKey`s, where each `DefKey`
26 /// stores the `DefIndex` of its parent.
27 /// There is one `DefPathTable` for each crate.
28 #[derive(Clone, Default, RustcDecodable, RustcEncodable)]
29 pub struct DefPathTable {
30 index_to_key: IndexVec<DefIndex, DefKey>,
31 def_path_hashes: IndexVec<DefIndex, DefPathHash>,
35 fn allocate(&mut self,
37 def_path_hash: DefPathHash)
40 let index = DefIndex::from(self.index_to_key.len());
41 debug!("DefPathTable::insert() - {:?} <-> {:?}", key, index);
42 self.index_to_key.push(key);
45 self.def_path_hashes.push(def_path_hash);
46 debug_assert!(self.def_path_hashes.len() == self.index_to_key.len());
50 pub fn next_id(&self) -> DefIndex {
51 DefIndex::from(self.index_to_key.len())
55 pub fn def_key(&self, index: DefIndex) -> DefKey {
56 self.index_to_key[index]
60 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
61 let hash = self.def_path_hashes[index];
62 debug!("def_path_hash({:?}) = {:?}", index, hash);
66 pub fn add_def_path_hashes_to(&self,
68 out: &mut FxHashMap<DefPathHash, DefId>) {
73 .map(|(index, &hash)| {
76 index: DefIndex::from(index),
83 pub fn size(&self) -> usize {
84 self.index_to_key.len()
88 /// The definition table containing node definitions.
89 /// It holds the `DefPathTable` for local `DefId`s/`DefPath`s and it also stores a
90 /// mapping from `NodeId`s to local `DefId`s.
91 #[derive(Clone, Default)]
92 pub struct Definitions {
94 node_to_def_index: NodeMap<DefIndex>,
95 def_index_to_node: IndexVec<DefIndex, ast::NodeId>,
96 pub(super) node_to_hir_id: IndexVec<ast::NodeId, hir::HirId>,
97 /// If `ExpnId` is an ID of some macro expansion,
98 /// then `DefId` is the normal module (`mod`) in which the expanded macro was defined.
99 parent_modules_of_macro_defs: FxHashMap<ExpnId, DefId>,
100 /// Item with a given `DefIndex` was defined during macro expansion with ID `ExpnId`.
101 expansions_that_defined: FxHashMap<DefIndex, ExpnId>,
102 next_disambiguator: FxHashMap<(DefIndex, DefPathData), u32>,
103 def_index_to_span: FxHashMap<DefIndex, Span>,
104 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
105 /// we know what parent node that fragment should be attached to thanks to this table.
106 invocation_parents: FxHashMap<ExpnId, DefIndex>,
107 /// Indices of unnamed struct or variant fields with unresolved attributes.
108 pub(super) placeholder_field_indices: NodeMap<usize>,
111 /// A unique identifier that we can use to lookup a definition
112 /// precisely. It combines the index of the definition's parent (if
113 /// any) with a `DisambiguatedDefPathData`.
114 #[derive(Copy, Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
117 pub parent: Option<DefIndex>,
119 /// The identifier of this node.
120 pub disambiguated_data: DisambiguatedDefPathData,
124 fn compute_stable_hash(&self, parent_hash: DefPathHash) -> DefPathHash {
125 let mut hasher = StableHasher::new();
127 // We hash a `0u8` here to disambiguate between regular `DefPath` hashes,
128 // and the special "root_parent" below.
129 0u8.hash(&mut hasher);
130 parent_hash.hash(&mut hasher);
132 let DisambiguatedDefPathData {
135 } = self.disambiguated_data;
137 ::std::mem::discriminant(data).hash(&mut hasher);
138 if let Some(name) = data.get_opt_name() {
139 // Get a stable hash by considering the symbol chars rather than
141 name.as_str().hash(&mut hasher);
144 disambiguator.hash(&mut hasher);
146 DefPathHash(hasher.finish())
149 fn root_parent_stable_hash(crate_name: &str,
150 crate_disambiguator: CrateDisambiguator)
152 let mut hasher = StableHasher::new();
153 // Disambiguate this from a regular `DefPath` hash; see `compute_stable_hash()` above.
154 1u8.hash(&mut hasher);
155 crate_name.hash(&mut hasher);
156 crate_disambiguator.hash(&mut hasher);
157 DefPathHash(hasher.finish())
161 /// A pair of `DefPathData` and an integer disambiguator. The integer is
162 /// normally `0`, but in the event that there are multiple defs with the
163 /// same `parent` and `data`, we use this field to disambiguate
164 /// between them. This introduces some artificial ordering dependency
165 /// but means that if you have, e.g., two impls for the same type in
166 /// the same module, they do get distinct `DefId`s.
167 #[derive(Copy, Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
168 pub struct DisambiguatedDefPathData {
169 pub data: DefPathData,
170 pub disambiguator: u32
173 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
175 /// The path leading from the crate root to the item.
176 pub data: Vec<DisambiguatedDefPathData>,
178 /// The crate root this path is relative to.
183 pub fn is_local(&self) -> bool {
184 self.krate == LOCAL_CRATE
187 pub fn make<FN>(krate: CrateNum,
188 start_index: DefIndex,
189 mut get_key: FN) -> DefPath
190 where FN: FnMut(DefIndex) -> DefKey
192 let mut data = vec![];
193 let mut index = Some(start_index);
195 debug!("DefPath::make: krate={:?} index={:?}", krate, index);
196 let p = index.unwrap();
197 let key = get_key(p);
198 debug!("DefPath::make: key={:?}", key);
199 match key.disambiguated_data.data {
200 DefPathData::CrateRoot => {
201 assert!(key.parent.is_none());
205 data.push(key.disambiguated_data);
211 DefPath { data: data, krate: krate }
214 /// Returns a string representation of the `DefPath` without
215 /// the crate-prefix. This method is useful if you don't have
216 /// a `TyCtxt` available.
217 pub fn to_string_no_crate(&self) -> String {
218 let mut s = String::with_capacity(self.data.len() * 16);
220 for component in &self.data {
223 component.data.as_symbol(),
224 component.disambiguator)
231 /// Returns a filename-friendly string for the `DefPath`, with the
233 pub fn to_string_friendly<F>(&self, crate_imported_name: F) -> String
234 where F: FnOnce(CrateNum) -> Symbol
236 let crate_name_str = crate_imported_name(self.krate).as_str();
237 let mut s = String::with_capacity(crate_name_str.len() + self.data.len() * 16);
239 write!(s, "::{}", crate_name_str).unwrap();
241 for component in &self.data {
242 if component.disambiguator == 0 {
243 write!(s, "::{}", component.data.as_symbol()).unwrap();
247 component.data.as_symbol(),
248 component.disambiguator)
256 /// Returns a filename-friendly string of the `DefPath`, without
257 /// the crate-prefix. This method is useful if you don't have
258 /// a `TyCtxt` available.
259 pub fn to_filename_friendly_no_crate(&self) -> String {
260 let mut s = String::with_capacity(self.data.len() * 16);
262 let mut opt_delimiter = None;
263 for component in &self.data {
264 opt_delimiter.map(|d| s.push(d));
265 opt_delimiter = Some('-');
266 if component.disambiguator == 0 {
267 write!(s, "{}", component.data.as_symbol()).unwrap();
271 component.data.as_symbol(),
272 component.disambiguator)
280 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
281 pub enum DefPathData {
282 // Root: these should only be used for the root nodes, because
283 // they are treated specially by the `def_path` function.
285 /// The crate root (marker).
287 // Catch-all for random `DefId` things like `DUMMY_NODE_ID`.
290 // Different kinds of items and item-like things:
294 /// Something in the type namespace.
296 /// Something in the value namespace.
298 /// Something in the macro namespace.
300 /// Something in the lifetime namespace.
302 /// A closure expression.
305 // Subportions of items:
307 /// Implicit constructor for a unit or tuple-like struct or enum variant.
309 /// A constant expression (see `{ast,hir}::AnonConst`).
311 /// An `impl Trait` type node.
315 #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug,
316 RustcEncodable, RustcDecodable)]
317 pub struct DefPathHash(pub Fingerprint);
319 impl_stable_hash_for!(tuple_struct DefPathHash { fingerprint });
321 impl Borrow<Fingerprint> for DefPathHash {
323 fn borrow(&self) -> &Fingerprint {
329 pub fn def_path_table(&self) -> &DefPathTable {
333 /// Gets the number of definitions.
334 pub fn def_index_count(&self) -> usize {
335 self.table.index_to_key.len()
338 pub fn def_key(&self, index: DefIndex) -> DefKey {
339 self.table.def_key(index)
343 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
344 self.table.def_path_hash(index)
347 /// Returns the path from the crate root to `index`. The root
348 /// nodes are not included in the path (i.e., this will be an
349 /// empty vector for the crate root). For an inlined item, this
350 /// will be the path of the item in the external crate (but the
351 /// path will begin with the path to the external crate).
352 pub fn def_path(&self, index: DefIndex) -> DefPath {
353 DefPath::make(LOCAL_CRATE, index, |p| self.def_key(p))
357 pub fn opt_def_index(&self, node: ast::NodeId) -> Option<DefIndex> {
358 self.node_to_def_index.get(&node).copied()
362 pub fn opt_local_def_id(&self, node: ast::NodeId) -> Option<DefId> {
363 self.opt_def_index(node).map(DefId::local)
367 pub fn local_def_id(&self, node: ast::NodeId) -> DefId {
368 self.opt_local_def_id(node).unwrap()
372 pub fn as_local_node_id(&self, def_id: DefId) -> Option<ast::NodeId> {
373 if def_id.krate == LOCAL_CRATE {
374 let node_id = self.def_index_to_node[def_id.index];
375 if node_id != ast::DUMMY_NODE_ID {
376 return Some(node_id);
383 pub fn as_local_hir_id(&self, def_id: DefId) -> Option<hir::HirId> {
384 if def_id.krate == LOCAL_CRATE {
385 let hir_id = self.def_index_to_hir_id(def_id.index);
386 if hir_id != hir::DUMMY_HIR_ID {
397 pub fn node_to_hir_id(&self, node_id: ast::NodeId) -> hir::HirId {
398 self.node_to_hir_id[node_id]
402 pub fn def_index_to_hir_id(&self, def_index: DefIndex) -> hir::HirId {
403 let node_id = self.def_index_to_node[def_index];
404 self.node_to_hir_id[node_id]
407 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate, the span exists
408 /// and it's not `DUMMY_SP`.
410 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
411 if def_id.krate == LOCAL_CRATE {
412 self.def_index_to_span.get(&def_id.index).copied()
418 /// Adds a root definition (no parent) and a few other reserved definitions.
419 pub fn create_root_def(&mut self,
421 crate_disambiguator: CrateDisambiguator)
425 disambiguated_data: DisambiguatedDefPathData {
426 data: DefPathData::CrateRoot,
431 let parent_hash = DefKey::root_parent_stable_hash(crate_name,
432 crate_disambiguator);
433 let def_path_hash = key.compute_stable_hash(parent_hash);
435 // Create the definition.
436 let root_index = self.table.allocate(key, def_path_hash);
437 assert_eq!(root_index, CRATE_DEF_INDEX);
438 assert!(self.def_index_to_node.is_empty());
439 self.def_index_to_node.push(ast::CRATE_NODE_ID);
440 self.node_to_def_index.insert(ast::CRATE_NODE_ID, root_index);
441 self.set_invocation_parent(ExpnId::root(), root_index);
446 /// Adds a definition with a parent definition.
447 pub fn create_def_with_parent(&mut self,
449 node_id: ast::NodeId,
454 debug!("create_def_with_parent(parent={:?}, node_id={:?}, data={:?})",
455 parent, node_id, data);
457 assert!(!self.node_to_def_index.contains_key(&node_id),
458 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
461 self.table.def_key(self.node_to_def_index[&node_id]));
463 // The root node must be created with `create_root_def()`.
464 assert!(data != DefPathData::CrateRoot);
466 // Find the next free disambiguator for this key.
467 let disambiguator = {
468 let next_disamb = self.next_disambiguator.entry((parent, data)).or_insert(0);
469 let disambiguator = *next_disamb;
470 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
475 parent: Some(parent),
476 disambiguated_data: DisambiguatedDefPathData {
481 let parent_hash = self.table.def_path_hash(parent);
482 let def_path_hash = key.compute_stable_hash(parent_hash);
484 debug!("create_def_with_parent: after disambiguation, key = {:?}", key);
486 // Create the definition.
487 let index = self.table.allocate(key, def_path_hash);
488 assert_eq!(index.index(), self.def_index_to_node.len());
489 self.def_index_to_node.push(node_id);
491 // Some things for which we allocate `DefIndex`es don't correspond to
492 // anything in the AST, so they don't have a `NodeId`. For these cases
493 // we don't need a mapping from `NodeId` to `DefIndex`.
494 if node_id != ast::DUMMY_NODE_ID {
495 debug!("create_def_with_parent: def_index_to_node[{:?} <-> {:?}", index, node_id);
496 self.node_to_def_index.insert(node_id, index);
499 if expn_id != ExpnId::root() {
500 self.expansions_that_defined.insert(index, expn_id);
503 // The span is added if it isn't dummy.
504 if !span.is_dummy() {
505 self.def_index_to_span.insert(index, span);
511 /// Initializes the `ast::NodeId` to `HirId` mapping once it has been generated during
512 /// AST to HIR lowering.
513 pub fn init_node_id_to_hir_id_mapping(&mut self,
514 mapping: IndexVec<ast::NodeId, hir::HirId>) {
515 assert!(self.node_to_hir_id.is_empty(),
516 "trying to initialize `NodeId` -> `HirId` mapping twice");
517 self.node_to_hir_id = mapping;
520 pub fn expansion_that_defined(&self, index: DefIndex) -> ExpnId {
521 self.expansions_that_defined.get(&index).copied().unwrap_or(ExpnId::root())
524 pub fn parent_module_of_macro_def(&self, expn_id: ExpnId) -> DefId {
525 self.parent_modules_of_macro_defs[&expn_id]
528 pub fn add_parent_module_of_macro_def(&mut self, expn_id: ExpnId, module: DefId) {
529 self.parent_modules_of_macro_defs.insert(expn_id, module);
532 pub fn invocation_parent(&self, invoc_id: ExpnId) -> DefIndex {
533 self.invocation_parents[&invoc_id]
536 pub fn set_invocation_parent(&mut self, invoc_id: ExpnId, parent: DefIndex) {
537 let old_parent = self.invocation_parents.insert(invoc_id, parent);
538 assert!(old_parent.is_none(), "parent `DefIndex` is reset for an invocation");
543 pub fn get_opt_name(&self) -> Option<Symbol> {
544 use self::DefPathData::*;
549 LifetimeNs(name) => Some(name),
561 pub fn as_symbol(&self) -> Symbol {
562 use self::DefPathData::*;
567 LifetimeNs(name) => {
570 // Note that this does not show up in user print-outs.
571 CrateRoot => sym::double_braced_crate,
572 Impl => sym::double_braced_impl,
573 Misc => sym::double_braced_misc,
574 ClosureExpr => sym::double_braced_closure,
575 Ctor => sym::double_braced_constructor,
576 AnonConst => sym::double_braced_constant,
577 ImplTrait => sym::double_braced_opaque,
581 pub fn to_string(&self) -> String {
582 self.as_symbol().to_string()