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 rustc_data_structures::fx::FxHashMap;
11 use rustc_data_structures::indexed_vec::{IndexVec};
12 use rustc_data_structures::stable_hasher::StableHasher;
13 use crate::session::CrateDisambiguator;
14 use std::borrow::Borrow;
18 use syntax::ext::hygiene::ExpnId;
19 use syntax::symbol::{Symbol, sym, InternedString};
20 use syntax_pos::{Span, DUMMY_SP};
21 use crate::util::nodemap::NodeMap;
23 /// The DefPathTable maps DefIndexes to DefKeys and vice versa.
24 /// Internally the DefPathTable holds a tree of DefKeys, where each DefKey
25 /// stores the DefIndex of its parent.
26 /// There is one DefPathTable for each crate.
27 #[derive(Clone, Default, RustcDecodable, RustcEncodable)]
28 pub struct DefPathTable {
29 index_to_key: Vec<DefKey>,
30 def_path_hashes: Vec<DefPathHash>,
34 fn allocate(&mut self,
36 def_path_hash: DefPathHash)
39 let index = DefIndex::from(self.index_to_key.len());
40 debug!("DefPathTable::insert() - {:?} <-> {:?}", key, index);
41 self.index_to_key.push(key);
44 self.def_path_hashes.push(def_path_hash);
45 debug_assert!(self.def_path_hashes.len() == self.index_to_key.len());
49 pub fn next_id(&self) -> DefIndex {
50 DefIndex::from(self.index_to_key.len())
54 pub fn def_key(&self, index: DefIndex) -> DefKey {
55 self.index_to_key[index.index()].clone()
59 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
60 let ret = self.def_path_hashes[index.index()];
61 debug!("def_path_hash({:?}) = {:?}", index, ret);
65 pub fn add_def_path_hashes_to(&self,
67 out: &mut FxHashMap<DefPathHash, DefId>) {
72 .map(|(index, &hash)| {
75 index: DefIndex::from(index),
82 pub fn size(&self) -> usize {
83 self.index_to_key.len()
87 /// The definition table containing node definitions.
88 /// It holds the `DefPathTable` for local `DefId`s/`DefPath`s and it also stores a
89 /// mapping from `NodeId`s to local `DefId`s.
90 #[derive(Clone, Default)]
91 pub struct Definitions {
93 node_to_def_index: NodeMap<DefIndex>,
94 def_index_to_node: Vec<ast::NodeId>,
95 pub(super) node_to_hir_id: IndexVec<ast::NodeId, hir::HirId>,
96 /// If `ExpnId` is an ID of some macro expansion,
97 /// then `DefId` is the normal module (`mod`) in which the expanded macro was defined.
98 parent_modules_of_macro_defs: FxHashMap<ExpnId, DefId>,
99 /// Item with a given `DefIndex` was defined during macro expansion with ID `ExpnId`.
100 expansions_that_defined: FxHashMap<DefIndex, ExpnId>,
101 next_disambiguator: FxHashMap<(DefIndex, DefPathData), u32>,
102 def_index_to_span: FxHashMap<DefIndex, Span>,
103 /// When collecting definitions from an AST fragment produced by a macro invocation `ExpnId`
104 /// we know what parent node that fragment should be attached to thanks to this table.
105 invocation_parents: FxHashMap<ExpnId, DefIndex>,
108 /// A unique identifier that we can use to lookup a definition
109 /// precisely. It combines the index of the definition's parent (if
110 /// any) with a `DisambiguatedDefPathData`.
111 #[derive(Clone, PartialEq, Debug, Hash, RustcEncodable, RustcDecodable)]
114 pub parent: Option<DefIndex>,
116 /// The identifier of this node.
117 pub disambiguated_data: DisambiguatedDefPathData,
121 fn compute_stable_hash(&self, parent_hash: DefPathHash) -> DefPathHash {
122 let mut hasher = StableHasher::new();
124 // We hash a 0u8 here to disambiguate between regular DefPath hashes,
125 // and the special "root_parent" below.
126 0u8.hash(&mut hasher);
127 parent_hash.hash(&mut hasher);
129 let DisambiguatedDefPathData {
132 } = self.disambiguated_data;
134 ::std::mem::discriminant(data).hash(&mut hasher);
135 if let Some(name) = data.get_opt_name() {
136 name.hash(&mut hasher);
139 disambiguator.hash(&mut hasher);
141 DefPathHash(hasher.finish())
144 fn root_parent_stable_hash(crate_name: &str,
145 crate_disambiguator: CrateDisambiguator)
147 let mut hasher = StableHasher::new();
148 // Disambiguate this from a regular DefPath hash,
149 // 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.
280 /// The crate root (marker)
282 // Catch-all for random DefId things like `DUMMY_NODE_ID`
284 // Different kinds of items and item-like things:
287 /// Something in the type NS
288 TypeNs(InternedString),
289 /// Something in the value NS
290 ValueNs(InternedString),
291 /// Something in the macro NS
292 MacroNs(InternedString),
293 /// Something in the lifetime NS
294 LifetimeNs(InternedString),
295 /// A closure expression
297 // Subportions of items
298 /// Implicit ctor for a unit or tuple-like struct or enum variant.
300 /// A constant expression (see {ast,hir}::AnonConst).
302 /// An `impl Trait` type node
304 /// Identifies a piece of crate metadata that is global to a whole crate
305 /// (as opposed to just one item). `GlobalMetaData` components are only
306 /// supposed to show up right below the crate root.
307 GlobalMetaData(InternedString),
310 #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug,
311 RustcEncodable, RustcDecodable)]
312 pub struct DefPathHash(pub Fingerprint);
314 impl_stable_hash_for!(tuple_struct DefPathHash { fingerprint });
316 impl Borrow<Fingerprint> for DefPathHash {
318 fn borrow(&self) -> &Fingerprint {
324 pub fn def_path_table(&self) -> &DefPathTable {
328 /// Gets the number of definitions.
329 pub fn def_index_count(&self) -> usize {
330 self.table.index_to_key.len()
333 pub fn def_key(&self, index: DefIndex) -> DefKey {
334 self.table.def_key(index)
338 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
339 self.table.def_path_hash(index)
342 /// Returns the path from the crate root to `index`. The root
343 /// nodes are not included in the path (i.e., this will be an
344 /// empty vector for the crate root). For an inlined item, this
345 /// will be the path of the item in the external crate (but the
346 /// path will begin with the path to the external crate).
347 pub fn def_path(&self, index: DefIndex) -> DefPath {
348 DefPath::make(LOCAL_CRATE, index, |p| self.def_key(p))
352 pub fn opt_def_index(&self, node: ast::NodeId) -> Option<DefIndex> {
353 self.node_to_def_index.get(&node).cloned()
357 pub fn opt_local_def_id(&self, node: ast::NodeId) -> Option<DefId> {
358 self.opt_def_index(node).map(DefId::local)
362 pub fn local_def_id(&self, node: ast::NodeId) -> DefId {
363 self.opt_local_def_id(node).unwrap()
367 pub fn as_local_node_id(&self, def_id: DefId) -> Option<ast::NodeId> {
368 if def_id.krate == LOCAL_CRATE {
369 let node_id = self.def_index_to_node[def_id.index.index()];
370 if node_id != ast::DUMMY_NODE_ID {
371 return Some(node_id);
378 pub fn as_local_hir_id(&self, def_id: DefId) -> Option<hir::HirId> {
379 if def_id.krate == LOCAL_CRATE {
380 let hir_id = self.def_index_to_hir_id(def_id.index);
381 if hir_id != hir::DUMMY_HIR_ID {
392 pub fn node_to_hir_id(&self, node_id: ast::NodeId) -> hir::HirId {
393 self.node_to_hir_id[node_id]
397 pub fn def_index_to_hir_id(&self, def_index: DefIndex) -> hir::HirId {
398 let node_id = self.def_index_to_node[def_index.index()];
399 self.node_to_hir_id[node_id]
402 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate, the span exists
403 /// and it's not `DUMMY_SP`.
405 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
406 if def_id.krate == LOCAL_CRATE {
407 self.def_index_to_span.get(&def_id.index).cloned()
413 /// Adds a root definition (no parent) and a few other reserved definitions.
415 /// After the initial definitions are created the first `FIRST_FREE_DEF_INDEX` indexes
416 /// are taken, so the "user" indexes will be allocated starting with `FIRST_FREE_DEF_INDEX`
417 /// in ascending order.
418 pub fn create_root_def(&mut self,
420 crate_disambiguator: CrateDisambiguator)
424 disambiguated_data: DisambiguatedDefPathData {
425 data: DefPathData::CrateRoot,
430 let parent_hash = DefKey::root_parent_stable_hash(crate_name,
431 crate_disambiguator);
432 let def_path_hash = key.compute_stable_hash(parent_hash);
434 // Create the definition.
435 let root_index = self.table.allocate(key, def_path_hash);
436 assert_eq!(root_index, CRATE_DEF_INDEX);
437 assert!(self.def_index_to_node.is_empty());
438 self.def_index_to_node.push(ast::CRATE_NODE_ID);
439 self.node_to_def_index.insert(ast::CRATE_NODE_ID, root_index);
440 self.set_invocation_parent(ExpnId::root(), root_index);
442 // Allocate some other DefIndices that always must exist.
443 GlobalMetaDataKind::allocate_def_indices(self);
448 /// Adds a definition with a parent definition.
449 pub fn create_def_with_parent(&mut self,
451 node_id: ast::NodeId,
456 debug!("create_def_with_parent(parent={:?}, node_id={:?}, data={:?})",
457 parent, node_id, data);
459 assert!(!self.node_to_def_index.contains_key(&node_id),
460 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
463 self.table.def_key(self.node_to_def_index[&node_id]));
465 // The root node must be created with create_root_def()
466 assert!(data != DefPathData::CrateRoot);
468 // Find the next free disambiguator for this key.
469 let disambiguator = {
470 let next_disamb = self.next_disambiguator.entry((parent, data.clone())).or_insert(0);
471 let disambiguator = *next_disamb;
472 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
477 parent: Some(parent),
478 disambiguated_data: DisambiguatedDefPathData {
483 let parent_hash = self.table.def_path_hash(parent);
484 let def_path_hash = key.compute_stable_hash(parent_hash);
486 debug!("create_def_with_parent: after disambiguation, key = {:?}", key);
488 // Create the definition.
489 let index = self.table.allocate(key, def_path_hash);
490 assert_eq!(index.index(), self.def_index_to_node.len());
491 self.def_index_to_node.push(node_id);
493 // Some things for which we allocate DefIndices don't correspond to
494 // anything in the AST, so they don't have a NodeId. For these cases
495 // we don't need a mapping from NodeId to DefIndex.
496 if node_id != ast::DUMMY_NODE_ID {
497 debug!("create_def_with_parent: def_index_to_node[{:?} <-> {:?}", index, node_id);
498 self.node_to_def_index.insert(node_id, index);
501 if expn_id != ExpnId::root() {
502 self.expansions_that_defined.insert(index, expn_id);
505 // The span is added if it isn't dummy
506 if !span.is_dummy() {
507 self.def_index_to_span.insert(index, span);
513 /// Initialize the `ast::NodeId` to `HirId` mapping once it has been generated during
514 /// AST to HIR lowering.
515 pub fn init_node_id_to_hir_id_mapping(&mut self,
516 mapping: IndexVec<ast::NodeId, hir::HirId>) {
517 assert!(self.node_to_hir_id.is_empty(),
518 "Trying initialize NodeId -> HirId mapping twice");
519 self.node_to_hir_id = mapping;
522 pub fn expansion_that_defined(&self, index: DefIndex) -> ExpnId {
523 self.expansions_that_defined.get(&index).cloned().unwrap_or(ExpnId::root())
526 pub fn parent_module_of_macro_def(&self, expn_id: ExpnId) -> DefId {
527 self.parent_modules_of_macro_defs[&expn_id]
530 pub fn add_parent_module_of_macro_def(&mut self, expn_id: ExpnId, module: DefId) {
531 self.parent_modules_of_macro_defs.insert(expn_id, module);
534 pub fn invocation_parent(&self, invoc_id: ExpnId) -> DefIndex {
535 self.invocation_parents[&invoc_id]
538 pub fn set_invocation_parent(&mut self, invoc_id: ExpnId, parent: DefIndex) {
539 let old_parent = self.invocation_parents.insert(invoc_id, parent);
540 assert!(old_parent.is_none(), "parent def-index is reset for an invocation");
545 pub fn get_opt_name(&self) -> Option<InternedString> {
546 use self::DefPathData::*;
552 GlobalMetaData(name) => Some(name),
564 pub fn as_interned_str(&self) -> InternedString {
565 use self::DefPathData::*;
566 let s = match *self {
571 GlobalMetaData(name) => {
574 // Note that this does not show up in user print-outs.
575 CrateRoot => sym::double_braced_crate,
576 Impl => sym::double_braced_impl,
577 Misc => sym::double_braced_misc,
578 ClosureExpr => sym::double_braced_closure,
579 Ctor => sym::double_braced_constructor,
580 AnonConst => sym::double_braced_constant,
581 ImplTrait => sym::double_braced_opaque,
587 pub fn to_string(&self) -> String {
588 self.as_interned_str().to_string()
592 /// Evaluates to the number of tokens passed to it.
594 /// Logarithmic counting: every one or two recursive expansions, the number of
595 /// tokens to count is divided by two, instead of being reduced by one.
596 /// Therefore, the recursion depth is the binary logarithm of the number of
597 /// tokens to count, and the expanded tree is likewise very small.
600 ($one:tt) => (1usize);
601 ($($pairs:tt $_p:tt)*) => (count!($($pairs)*) << 1usize);
602 ($odd:tt $($rest:tt)*) => (count!($($rest)*) | 1usize);
605 // We define the GlobalMetaDataKind enum with this macro because we want to
606 // make sure that we exhaustively iterate over all variants when registering
607 // the corresponding DefIndices in the DefTable.
608 macro_rules! define_global_metadata_kind {
609 (pub enum GlobalMetaDataKind {
612 #[derive(Clone, Copy, Debug, Hash, RustcEncodable, RustcDecodable)]
613 pub enum GlobalMetaDataKind {
617 pub const FIRST_FREE_DEF_INDEX: usize = 1 + count!($($variant)*);
619 impl GlobalMetaDataKind {
620 fn allocate_def_indices(definitions: &mut Definitions) {
622 let instance = GlobalMetaDataKind::$variant;
623 definitions.create_def_with_parent(
626 DefPathData::GlobalMetaData(instance.name().as_interned_str()),
631 // Make sure calling def_index does not crash.
632 instance.def_index(&definitions.table);
636 pub fn def_index(&self, def_path_table: &DefPathTable) -> DefIndex {
637 let def_key = DefKey {
638 parent: Some(CRATE_DEF_INDEX),
639 disambiguated_data: DisambiguatedDefPathData {
640 data: DefPathData::GlobalMetaData(self.name().as_interned_str()),
645 // These DefKeys are all right after the root,
646 // so a linear search is fine.
647 let index = def_path_table.index_to_key
649 .position(|k| *k == def_key)
652 DefIndex::from(index)
655 fn name(&self) -> Symbol {
657 let string = match *self {
659 GlobalMetaDataKind::$variant => {
660 concat!("{{GlobalMetaData::", stringify!($variant), "}}")
665 Symbol::intern(string)
671 define_global_metadata_kind!(pub enum GlobalMetaDataKind {
674 DylibDependencyFormats,