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_data_structures::indexed_vec::{IndexVec};
15 use rustc_data_structures::stable_hasher::StableHasher;
16 use std::borrow::Borrow;
20 use syntax::ext::hygiene::ExpnId;
21 use syntax::symbol::{Symbol, sym, InternedString};
22 use syntax_pos::{Span, DUMMY_SP};
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: Vec<DefKey>,
31 def_path_hashes: Vec<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.index()].clone()
60 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
61 let ret = self.def_path_hashes[index.index()];
62 debug!("def_path_hash({:?}) = {:?}", index, ret);
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: Vec<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>,
109 /// A unique identifier that we can use to lookup a definition
110 /// precisely. It combines the index of the definition's parent (if
111 /// any) with a `DisambiguatedDefPathData`.
112 #[derive(Clone, PartialEq, Debug, Hash, RustcEncodable, RustcDecodable)]
115 pub parent: Option<DefIndex>,
117 /// The identifier of this node.
118 pub disambiguated_data: DisambiguatedDefPathData,
122 fn compute_stable_hash(&self, parent_hash: DefPathHash) -> DefPathHash {
123 let mut hasher = StableHasher::new();
125 // We hash a `0u8` here to disambiguate between regular `DefPath` hashes,
126 // and the special "root_parent" below.
127 0u8.hash(&mut hasher);
128 parent_hash.hash(&mut hasher);
130 let DisambiguatedDefPathData {
133 } = self.disambiguated_data;
135 ::std::mem::discriminant(data).hash(&mut hasher);
136 if let Some(name) = data.get_opt_name() {
137 name.hash(&mut hasher);
140 disambiguator.hash(&mut hasher);
142 DefPathHash(hasher.finish())
145 fn root_parent_stable_hash(crate_name: &str,
146 crate_disambiguator: CrateDisambiguator)
148 let mut hasher = StableHasher::new();
149 // Disambiguate this from a regular `DefPath` hash; see `compute_stable_hash()` above.
150 1u8.hash(&mut hasher);
151 crate_name.hash(&mut hasher);
152 crate_disambiguator.hash(&mut hasher);
153 DefPathHash(hasher.finish())
157 /// A pair of `DefPathData` and an integer disambiguator. The integer is
158 /// normally `0`, but in the event that there are multiple defs with the
159 /// same `parent` and `data`, we use this field to disambiguate
160 /// between them. This introduces some artificial ordering dependency
161 /// but means that if you have, e.g., two impls for the same type in
162 /// the same module, they do get distinct `DefId`s.
163 #[derive(Clone, PartialEq, Debug, Hash, RustcEncodable, RustcDecodable)]
164 pub struct DisambiguatedDefPathData {
165 pub data: DefPathData,
166 pub disambiguator: u32
169 #[derive(Clone, Debug, Hash, RustcEncodable, RustcDecodable)]
171 /// The path leading from the crate root to the item.
172 pub data: Vec<DisambiguatedDefPathData>,
174 /// The crate root this path is relative to.
179 pub fn is_local(&self) -> bool {
180 self.krate == LOCAL_CRATE
183 pub fn make<FN>(krate: CrateNum,
184 start_index: DefIndex,
185 mut get_key: FN) -> DefPath
186 where FN: FnMut(DefIndex) -> DefKey
188 let mut data = vec![];
189 let mut index = Some(start_index);
191 debug!("DefPath::make: krate={:?} index={:?}", krate, index);
192 let p = index.unwrap();
193 let key = get_key(p);
194 debug!("DefPath::make: key={:?}", key);
195 match key.disambiguated_data.data {
196 DefPathData::CrateRoot => {
197 assert!(key.parent.is_none());
201 data.push(key.disambiguated_data);
207 DefPath { data: data, krate: krate }
210 /// Returns a string representation of the `DefPath` without
211 /// the crate-prefix. This method is useful if you don't have
212 /// a `TyCtxt` available.
213 pub fn to_string_no_crate(&self) -> String {
214 let mut s = String::with_capacity(self.data.len() * 16);
216 for component in &self.data {
219 component.data.as_interned_str(),
220 component.disambiguator)
227 /// Returns a filename-friendly string for the `DefPath`, with the
229 pub fn to_string_friendly<F>(&self, crate_imported_name: F) -> String
230 where F: FnOnce(CrateNum) -> Symbol
232 let crate_name_str = crate_imported_name(self.krate).as_str();
233 let mut s = String::with_capacity(crate_name_str.len() + self.data.len() * 16);
235 write!(s, "::{}", crate_name_str).unwrap();
237 for component in &self.data {
238 if component.disambiguator == 0 {
239 write!(s, "::{}", component.data.as_interned_str()).unwrap();
243 component.data.as_interned_str(),
244 component.disambiguator)
252 /// Returns a filename-friendly string of the `DefPath`, without
253 /// the crate-prefix. This method is useful if you don't have
254 /// a `TyCtxt` available.
255 pub fn to_filename_friendly_no_crate(&self) -> String {
256 let mut s = String::with_capacity(self.data.len() * 16);
258 let mut opt_delimiter = None;
259 for component in &self.data {
260 opt_delimiter.map(|d| s.push(d));
261 opt_delimiter = Some('-');
262 if component.disambiguator == 0 {
263 write!(s, "{}", component.data.as_interned_str()).unwrap();
267 component.data.as_interned_str(),
268 component.disambiguator)
276 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
277 pub enum DefPathData {
278 // Root: these should only be used for the root nodes, because
279 // they are treated specially by the `def_path` function.
281 /// The crate root (marker).
283 // Catch-all for random `DefId` things like `DUMMY_NODE_ID`.
286 // Different kinds of items and item-like things:
290 /// Something in the type namespace.
291 TypeNs(InternedString),
292 /// Something in the value namespace.
293 ValueNs(InternedString),
294 /// Something in the macro namespace.
295 MacroNs(InternedString),
296 /// Something in the lifetime namespace.
297 LifetimeNs(InternedString),
298 /// A closure expression.
301 // Subportions of items:
303 /// Implicit constructor for a unit or tuple-like struct or enum variant.
305 /// A constant expression (see `{ast,hir}::AnonConst`).
307 /// An `impl Trait` type node.
309 /// Identifies a piece of crate metadata that is global to a whole crate
310 /// (as opposed to just one item). `GlobalMetaData` components are only
311 /// supposed to show up right below the crate root.
312 GlobalMetaData(InternedString),
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).cloned()
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.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.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).cloned()
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);
443 // Allocate some other `DefIndex`es that always must exist.
444 GlobalMetaDataKind::allocate_def_indices(self);
449 /// Adds a definition with a parent definition.
450 pub fn create_def_with_parent(&mut self,
452 node_id: ast::NodeId,
457 debug!("create_def_with_parent(parent={:?}, node_id={:?}, data={:?})",
458 parent, node_id, data);
460 assert!(!self.node_to_def_index.contains_key(&node_id),
461 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
464 self.table.def_key(self.node_to_def_index[&node_id]));
466 // The root node must be created with `create_root_def()`.
467 assert!(data != DefPathData::CrateRoot);
469 // Find the next free disambiguator for this key.
470 let disambiguator = {
471 let next_disamb = self.next_disambiguator.entry((parent, data.clone())).or_insert(0);
472 let disambiguator = *next_disamb;
473 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
478 parent: Some(parent),
479 disambiguated_data: DisambiguatedDefPathData {
484 let parent_hash = self.table.def_path_hash(parent);
485 let def_path_hash = key.compute_stable_hash(parent_hash);
487 debug!("create_def_with_parent: after disambiguation, key = {:?}", key);
489 // Create the definition.
490 let index = self.table.allocate(key, def_path_hash);
491 assert_eq!(index.index(), self.def_index_to_node.len());
492 self.def_index_to_node.push(node_id);
494 // Some things for which we allocate `DefIndex`es don't correspond to
495 // anything in the AST, so they don't have a `NodeId`. For these cases
496 // we don't need a mapping from `NodeId` to `DefIndex`.
497 if node_id != ast::DUMMY_NODE_ID {
498 debug!("create_def_with_parent: def_index_to_node[{:?} <-> {:?}", index, node_id);
499 self.node_to_def_index.insert(node_id, index);
502 if expn_id != ExpnId::root() {
503 self.expansions_that_defined.insert(index, expn_id);
506 // The span is added if it isn't dummy.
507 if !span.is_dummy() {
508 self.def_index_to_span.insert(index, span);
514 /// Initializes the `ast::NodeId` to `HirId` mapping once it has been generated during
515 /// AST to HIR lowering.
516 pub fn init_node_id_to_hir_id_mapping(&mut self,
517 mapping: IndexVec<ast::NodeId, hir::HirId>) {
518 assert!(self.node_to_hir_id.is_empty(),
519 "trying to initialize `NodeId` -> `HirId` mapping twice");
520 self.node_to_hir_id = mapping;
523 pub fn expansion_that_defined(&self, index: DefIndex) -> ExpnId {
524 self.expansions_that_defined.get(&index).cloned().unwrap_or(ExpnId::root())
527 pub fn parent_module_of_macro_def(&self, expn_id: ExpnId) -> DefId {
528 self.parent_modules_of_macro_defs[&expn_id]
531 pub fn add_parent_module_of_macro_def(&mut self, expn_id: ExpnId, module: DefId) {
532 self.parent_modules_of_macro_defs.insert(expn_id, module);
535 pub fn invocation_parent(&self, invoc_id: ExpnId) -> DefIndex {
536 self.invocation_parents[&invoc_id]
539 pub fn set_invocation_parent(&mut self, invoc_id: ExpnId, parent: DefIndex) {
540 let old_parent = self.invocation_parents.insert(invoc_id, parent);
541 assert!(old_parent.is_none(), "parent `DefIndex` is reset for an invocation");
546 pub fn get_opt_name(&self) -> Option<InternedString> {
547 use self::DefPathData::*;
553 GlobalMetaData(name) => Some(name),
565 pub fn as_interned_str(&self) -> InternedString {
566 use self::DefPathData::*;
567 let s = match *self {
572 GlobalMetaData(name) => {
575 // Note that this does not show up in user print-outs.
576 CrateRoot => sym::double_braced_crate,
577 Impl => sym::double_braced_impl,
578 Misc => sym::double_braced_misc,
579 ClosureExpr => sym::double_braced_closure,
580 Ctor => sym::double_braced_constructor,
581 AnonConst => sym::double_braced_constant,
582 ImplTrait => sym::double_braced_opaque,
588 pub fn to_string(&self) -> String {
589 self.as_interned_str().to_string()
593 // We define the `GlobalMetaDataKind` enum with this macro because we want to
594 // make sure that we exhaustively iterate over all variants when registering
595 // the corresponding `DefIndex`es in the `DefTable`.
596 macro_rules! define_global_metadata_kind {
597 (pub enum GlobalMetaDataKind {
600 #[derive(Clone, Copy, Debug, Hash, RustcEncodable, RustcDecodable)]
601 pub enum GlobalMetaDataKind {
605 impl GlobalMetaDataKind {
606 fn allocate_def_indices(definitions: &mut Definitions) {
608 let instance = GlobalMetaDataKind::$variant;
609 definitions.create_def_with_parent(
612 DefPathData::GlobalMetaData(instance.name().as_interned_str()),
617 // Make sure calling `def_index` does not crash.
618 instance.def_index(&definitions.table);
622 pub fn def_index(&self, def_path_table: &DefPathTable) -> DefIndex {
623 let def_key = DefKey {
624 parent: Some(CRATE_DEF_INDEX),
625 disambiguated_data: DisambiguatedDefPathData {
626 data: DefPathData::GlobalMetaData(self.name().as_interned_str()),
631 // These `DefKey`s are all right after the root,
632 // so a linear search is fine.
633 let index = def_path_table.index_to_key
635 .position(|k| *k == def_key)
638 DefIndex::from(index)
641 fn name(&self) -> Symbol {
643 let string = match *self {
645 GlobalMetaDataKind::$variant => {
646 concat!("{{GlobalMetaData::", stringify!($variant), "}}")
651 Symbol::intern(string)
657 define_global_metadata_kind!(pub enum GlobalMetaDataKind {
660 DylibDependencyFormats,