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::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>,
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(Clone, PartialEq, Debug, Hash, 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 name.hash(&mut hasher);
142 disambiguator.hash(&mut hasher);
144 DefPathHash(hasher.finish())
147 fn root_parent_stable_hash(crate_name: &str,
148 crate_disambiguator: CrateDisambiguator)
150 let mut hasher = StableHasher::new();
151 // Disambiguate this from a regular `DefPath` hash; see `compute_stable_hash()` above.
152 1u8.hash(&mut hasher);
153 crate_name.hash(&mut hasher);
154 crate_disambiguator.hash(&mut hasher);
155 DefPathHash(hasher.finish())
159 /// A pair of `DefPathData` and an integer disambiguator. The integer is
160 /// normally `0`, but in the event that there are multiple defs with the
161 /// same `parent` and `data`, we use this field to disambiguate
162 /// between them. This introduces some artificial ordering dependency
163 /// but means that if you have, e.g., two impls for the same type in
164 /// the same module, they do get distinct `DefId`s.
165 #[derive(Clone, PartialEq, Debug, Hash, RustcEncodable, RustcDecodable)]
166 pub struct DisambiguatedDefPathData {
167 pub data: DefPathData,
168 pub disambiguator: u32
171 #[derive(Clone, Debug, Hash, RustcEncodable, RustcDecodable)]
173 /// The path leading from the crate root to the item.
174 pub data: Vec<DisambiguatedDefPathData>,
176 /// The crate root this path is relative to.
181 pub fn is_local(&self) -> bool {
182 self.krate == LOCAL_CRATE
185 pub fn make<FN>(krate: CrateNum,
186 start_index: DefIndex,
187 mut get_key: FN) -> DefPath
188 where FN: FnMut(DefIndex) -> DefKey
190 let mut data = vec![];
191 let mut index = Some(start_index);
193 debug!("DefPath::make: krate={:?} index={:?}", krate, index);
194 let p = index.unwrap();
195 let key = get_key(p);
196 debug!("DefPath::make: key={:?}", key);
197 match key.disambiguated_data.data {
198 DefPathData::CrateRoot => {
199 assert!(key.parent.is_none());
203 data.push(key.disambiguated_data);
209 DefPath { data: data, krate: krate }
212 /// Returns a string representation of the `DefPath` without
213 /// the crate-prefix. This method is useful if you don't have
214 /// a `TyCtxt` available.
215 pub fn to_string_no_crate(&self) -> String {
216 let mut s = String::with_capacity(self.data.len() * 16);
218 for component in &self.data {
221 component.data.as_interned_str(),
222 component.disambiguator)
229 /// Returns a filename-friendly string for the `DefPath`, with the
231 pub fn to_string_friendly<F>(&self, crate_imported_name: F) -> String
232 where F: FnOnce(CrateNum) -> Symbol
234 let crate_name_str = crate_imported_name(self.krate).as_str();
235 let mut s = String::with_capacity(crate_name_str.len() + self.data.len() * 16);
237 write!(s, "::{}", crate_name_str).unwrap();
239 for component in &self.data {
240 if component.disambiguator == 0 {
241 write!(s, "::{}", component.data.as_interned_str()).unwrap();
245 component.data.as_interned_str(),
246 component.disambiguator)
254 /// Returns a filename-friendly string of the `DefPath`, without
255 /// the crate-prefix. This method is useful if you don't have
256 /// a `TyCtxt` available.
257 pub fn to_filename_friendly_no_crate(&self) -> String {
258 let mut s = String::with_capacity(self.data.len() * 16);
260 let mut opt_delimiter = None;
261 for component in &self.data {
262 opt_delimiter.map(|d| s.push(d));
263 opt_delimiter = Some('-');
264 if component.disambiguator == 0 {
265 write!(s, "{}", component.data.as_interned_str()).unwrap();
269 component.data.as_interned_str(),
270 component.disambiguator)
278 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
279 pub enum DefPathData {
280 // Root: these should only be used for the root nodes, because
281 // they are treated specially by the `def_path` function.
283 /// The crate root (marker).
285 // Catch-all for random `DefId` things like `DUMMY_NODE_ID`.
288 // Different kinds of items and item-like things:
292 /// Something in the type namespace.
293 TypeNs(InternedString),
294 /// Something in the value namespace.
295 ValueNs(InternedString),
296 /// Something in the macro namespace.
297 MacroNs(InternedString),
298 /// Something in the lifetime namespace.
299 LifetimeNs(InternedString),
300 /// A closure expression.
303 // Subportions of items:
305 /// Implicit constructor for a unit or tuple-like struct or enum variant.
307 /// A constant expression (see `{ast,hir}::AnonConst`).
309 /// An `impl Trait` type node.
311 /// Identifies a piece of crate metadata that is global to a whole crate
312 /// (as opposed to just one item). `GlobalMetaData` components are only
313 /// supposed to show up right below the crate root.
314 GlobalMetaData(InternedString),
317 #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug,
318 RustcEncodable, RustcDecodable)]
319 pub struct DefPathHash(pub Fingerprint);
321 impl_stable_hash_for!(tuple_struct DefPathHash { fingerprint });
323 impl Borrow<Fingerprint> for DefPathHash {
325 fn borrow(&self) -> &Fingerprint {
331 pub fn def_path_table(&self) -> &DefPathTable {
335 /// Gets the number of definitions.
336 pub fn def_index_count(&self) -> usize {
337 self.table.index_to_key.len()
340 pub fn def_key(&self, index: DefIndex) -> DefKey {
341 self.table.def_key(index)
345 pub fn def_path_hash(&self, index: DefIndex) -> DefPathHash {
346 self.table.def_path_hash(index)
349 /// Returns the path from the crate root to `index`. The root
350 /// nodes are not included in the path (i.e., this will be an
351 /// empty vector for the crate root). For an inlined item, this
352 /// will be the path of the item in the external crate (but the
353 /// path will begin with the path to the external crate).
354 pub fn def_path(&self, index: DefIndex) -> DefPath {
355 DefPath::make(LOCAL_CRATE, index, |p| self.def_key(p))
359 pub fn opt_def_index(&self, node: ast::NodeId) -> Option<DefIndex> {
360 self.node_to_def_index.get(&node).cloned()
364 pub fn opt_local_def_id(&self, node: ast::NodeId) -> Option<DefId> {
365 self.opt_def_index(node).map(DefId::local)
369 pub fn local_def_id(&self, node: ast::NodeId) -> DefId {
370 self.opt_local_def_id(node).unwrap()
374 pub fn as_local_node_id(&self, def_id: DefId) -> Option<ast::NodeId> {
375 if def_id.krate == LOCAL_CRATE {
376 let node_id = self.def_index_to_node[def_id.index.index()];
377 if node_id != ast::DUMMY_NODE_ID {
378 return Some(node_id);
385 pub fn as_local_hir_id(&self, def_id: DefId) -> Option<hir::HirId> {
386 if def_id.krate == LOCAL_CRATE {
387 let hir_id = self.def_index_to_hir_id(def_id.index);
388 if hir_id != hir::DUMMY_HIR_ID {
399 pub fn node_to_hir_id(&self, node_id: ast::NodeId) -> hir::HirId {
400 self.node_to_hir_id[node_id]
404 pub fn def_index_to_hir_id(&self, def_index: DefIndex) -> hir::HirId {
405 let node_id = self.def_index_to_node[def_index.index()];
406 self.node_to_hir_id[node_id]
409 /// Retrieves the span of the given `DefId` if `DefId` is in the local crate, the span exists
410 /// and it's not `DUMMY_SP`.
412 pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
413 if def_id.krate == LOCAL_CRATE {
414 self.def_index_to_span.get(&def_id.index).cloned()
420 /// Adds a root definition (no parent) and a few other reserved definitions.
421 pub fn create_root_def(&mut self,
423 crate_disambiguator: CrateDisambiguator)
427 disambiguated_data: DisambiguatedDefPathData {
428 data: DefPathData::CrateRoot,
433 let parent_hash = DefKey::root_parent_stable_hash(crate_name,
434 crate_disambiguator);
435 let def_path_hash = key.compute_stable_hash(parent_hash);
437 // Create the definition.
438 let root_index = self.table.allocate(key, def_path_hash);
439 assert_eq!(root_index, CRATE_DEF_INDEX);
440 assert!(self.def_index_to_node.is_empty());
441 self.def_index_to_node.push(ast::CRATE_NODE_ID);
442 self.node_to_def_index.insert(ast::CRATE_NODE_ID, root_index);
443 self.set_invocation_parent(ExpnId::root(), root_index);
445 // Allocate some other `DefIndex`es that always must exist.
446 GlobalMetaDataKind::allocate_def_indices(self);
451 /// Adds a definition with a parent definition.
452 pub fn create_def_with_parent(&mut self,
454 node_id: ast::NodeId,
459 debug!("create_def_with_parent(parent={:?}, node_id={:?}, data={:?})",
460 parent, node_id, data);
462 assert!(!self.node_to_def_index.contains_key(&node_id),
463 "adding a def'n for node-id {:?} and data {:?} but a previous def'n exists: {:?}",
466 self.table.def_key(self.node_to_def_index[&node_id]));
468 // The root node must be created with `create_root_def()`.
469 assert!(data != DefPathData::CrateRoot);
471 // Find the next free disambiguator for this key.
472 let disambiguator = {
473 let next_disamb = self.next_disambiguator.entry((parent, data.clone())).or_insert(0);
474 let disambiguator = *next_disamb;
475 *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
480 parent: Some(parent),
481 disambiguated_data: DisambiguatedDefPathData {
486 let parent_hash = self.table.def_path_hash(parent);
487 let def_path_hash = key.compute_stable_hash(parent_hash);
489 debug!("create_def_with_parent: after disambiguation, key = {:?}", key);
491 // Create the definition.
492 let index = self.table.allocate(key, def_path_hash);
493 assert_eq!(index.index(), self.def_index_to_node.len());
494 self.def_index_to_node.push(node_id);
496 // Some things for which we allocate `DefIndex`es don't correspond to
497 // anything in the AST, so they don't have a `NodeId`. For these cases
498 // we don't need a mapping from `NodeId` to `DefIndex`.
499 if node_id != ast::DUMMY_NODE_ID {
500 debug!("create_def_with_parent: def_index_to_node[{:?} <-> {:?}", index, node_id);
501 self.node_to_def_index.insert(node_id, index);
504 if expn_id != ExpnId::root() {
505 self.expansions_that_defined.insert(index, expn_id);
508 // The span is added if it isn't dummy.
509 if !span.is_dummy() {
510 self.def_index_to_span.insert(index, span);
516 /// Initializes the `ast::NodeId` to `HirId` mapping once it has been generated during
517 /// AST to HIR lowering.
518 pub fn init_node_id_to_hir_id_mapping(&mut self,
519 mapping: IndexVec<ast::NodeId, hir::HirId>) {
520 assert!(self.node_to_hir_id.is_empty(),
521 "trying to initialize `NodeId` -> `HirId` mapping twice");
522 self.node_to_hir_id = mapping;
525 pub fn expansion_that_defined(&self, index: DefIndex) -> ExpnId {
526 self.expansions_that_defined.get(&index).cloned().unwrap_or(ExpnId::root())
529 pub fn parent_module_of_macro_def(&self, expn_id: ExpnId) -> DefId {
530 self.parent_modules_of_macro_defs[&expn_id]
533 pub fn add_parent_module_of_macro_def(&mut self, expn_id: ExpnId, module: DefId) {
534 self.parent_modules_of_macro_defs.insert(expn_id, module);
537 pub fn invocation_parent(&self, invoc_id: ExpnId) -> DefIndex {
538 self.invocation_parents[&invoc_id]
541 pub fn set_invocation_parent(&mut self, invoc_id: ExpnId, parent: DefIndex) {
542 let old_parent = self.invocation_parents.insert(invoc_id, parent);
543 assert!(old_parent.is_none(), "parent `DefIndex` is reset for an invocation");
548 pub fn get_opt_name(&self) -> Option<InternedString> {
549 use self::DefPathData::*;
555 GlobalMetaData(name) => Some(name),
567 pub fn as_interned_str(&self) -> InternedString {
568 use self::DefPathData::*;
569 let s = match *self {
574 GlobalMetaData(name) => {
577 // Note that this does not show up in user print-outs.
578 CrateRoot => sym::double_braced_crate,
579 Impl => sym::double_braced_impl,
580 Misc => sym::double_braced_misc,
581 ClosureExpr => sym::double_braced_closure,
582 Ctor => sym::double_braced_constructor,
583 AnonConst => sym::double_braced_constant,
584 ImplTrait => sym::double_braced_opaque,
590 pub fn to_string(&self) -> String {
591 self.as_interned_str().to_string()
595 // We define the `GlobalMetaDataKind` enum with this macro because we want to
596 // make sure that we exhaustively iterate over all variants when registering
597 // the corresponding `DefIndex`es in the `DefTable`.
598 macro_rules! define_global_metadata_kind {
599 (pub enum GlobalMetaDataKind {
602 #[derive(Clone, Copy, Debug, Hash, RustcEncodable, RustcDecodable)]
603 pub enum GlobalMetaDataKind {
607 impl GlobalMetaDataKind {
608 fn allocate_def_indices(definitions: &mut Definitions) {
610 let instance = GlobalMetaDataKind::$variant;
611 definitions.create_def_with_parent(
614 DefPathData::GlobalMetaData(instance.name().as_interned_str()),
619 // Make sure calling `def_index` does not crash.
620 instance.def_index(&definitions.table);
624 pub fn def_index(&self, def_path_table: &DefPathTable) -> DefIndex {
625 let def_key = DefKey {
626 parent: Some(CRATE_DEF_INDEX),
627 disambiguated_data: DisambiguatedDefPathData {
628 data: DefPathData::GlobalMetaData(self.name().as_interned_str()),
633 // These `DefKey`s are all right after the root,
634 // so a linear search is fine.
635 let index = def_path_table.index_to_key
637 .position(|k| *k == def_key)
640 DefIndex::from(index)
643 fn name(&self) -> Symbol {
645 let string = match *self {
647 GlobalMetaDataKind::$variant => {
648 concat!("{{GlobalMetaData::", stringify!($variant), "}}")
653 Symbol::intern(string)
659 define_global_metadata_kind!(pub enum GlobalMetaDataKind {
662 DylibDependencyFormats,