1 use crate::dep_graph::{DepNode, DepNodeIndex, SerializedDepNodeIndex};
2 use crate::mir::interpret::{AllocDecodingSession, AllocDecodingState};
3 use crate::mir::{self, interpret};
4 use crate::ty::codec::{RefDecodable, TyDecoder, TyEncoder};
5 use crate::ty::context::TyCtxt;
6 use crate::ty::{self, Ty};
7 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
8 use rustc_data_structures::sync::{HashMapExt, Lock, Lrc, OnceCell};
9 use rustc_data_structures::thin_vec::ThinVec;
10 use rustc_data_structures::unhash::UnhashMap;
11 use rustc_errors::Diagnostic;
12 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, LOCAL_CRATE};
13 use rustc_hir::definitions::{DefPathHash, DefPathTable};
14 use rustc_index::vec::{Idx, IndexVec};
15 use rustc_query_system::dep_graph::DepContext;
16 use rustc_query_system::query::QueryContext;
17 use rustc_serialize::{
18 opaque::{self, FileEncodeResult, FileEncoder, IntEncodedWithFixedSize},
19 Decodable, Decoder, Encodable, Encoder,
21 use rustc_session::{Session, StableCrateId};
22 use rustc_span::hygiene::{
23 ExpnDataDecodeMode, ExpnDataEncodeMode, ExpnId, HygieneDecodeContext, HygieneEncodeContext,
24 SyntaxContext, SyntaxContextData,
26 use rustc_span::source_map::{SourceMap, StableSourceFileId};
27 use rustc_span::CachingSourceMapView;
28 use rustc_span::{BytePos, ExpnData, SourceFile, Span, DUMMY_SP};
29 use std::collections::hash_map::Entry;
30 use std::iter::FromIterator;
33 const TAG_FILE_FOOTER: u128 = 0xC0FFEE_C0FFEE_C0FFEE_C0FFEE_C0FFEE;
35 // A normal span encoded with both location information and a `SyntaxContext`
36 const TAG_FULL_SPAN: u8 = 0;
37 // A partial span with no location information, encoded only with a `SyntaxContext`
38 const TAG_PARTIAL_SPAN: u8 = 1;
40 const TAG_SYNTAX_CONTEXT: u8 = 0;
41 const TAG_EXPN_DATA: u8 = 1;
43 /// Provides an interface to incremental compilation data cached from the
44 /// previous compilation session. This data will eventually include the results
45 /// of a few selected queries (like `typeck` and `mir_optimized`) and
46 /// any diagnostics that have been emitted during a query.
47 pub struct OnDiskCache<'sess> {
48 // The complete cache data in serialized form.
49 serialized_data: Vec<u8>,
51 // Collects all `Diagnostic`s emitted during the current compilation
53 current_diagnostics: Lock<FxHashMap<DepNodeIndex, Vec<Diagnostic>>>,
55 prev_cnums: Vec<(u32, StableCrateId)>,
56 cnum_map: OnceCell<IndexVec<CrateNum, Option<CrateNum>>>,
58 source_map: &'sess SourceMap,
59 file_index_to_stable_id: FxHashMap<SourceFileIndex, StableSourceFileId>,
61 // Caches that are populated lazily during decoding.
62 file_index_to_file: Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
64 // A map from dep-node to the position of the cached query result in
66 query_result_index: FxHashMap<SerializedDepNodeIndex, AbsoluteBytePos>,
68 // A map from dep-node to the position of any associated diagnostics in
70 prev_diagnostics_index: FxHashMap<SerializedDepNodeIndex, AbsoluteBytePos>,
72 alloc_decoding_state: AllocDecodingState,
74 // A map from syntax context ids to the position of their associated
75 // `SyntaxContextData`. We use a `u32` instead of a `SyntaxContext`
76 // to represent the fact that we are storing *encoded* ids. When we decode
77 // a `SyntaxContext`, a new id will be allocated from the global `HygieneData`,
78 // which will almost certainly be different than the serialized id.
79 syntax_contexts: FxHashMap<u32, AbsoluteBytePos>,
80 // A map from the `DefPathHash` of an `ExpnId` to the position
81 // of their associated `ExpnData`. Ideally, we would store a `DefId`,
82 // but we need to decode this before we've constructed a `TyCtxt` (which
83 // makes it difficult to decode a `DefId`).
85 // Note that these `DefPathHashes` correspond to both local and foreign
86 // `ExpnData` (e.g `ExpnData.krate` may not be `LOCAL_CRATE`). Alternatively,
87 // we could look up the `ExpnData` from the metadata of foreign crates,
88 // but it seemed easier to have `OnDiskCache` be independent of the `CStore`.
89 expn_data: FxHashMap<u32, AbsoluteBytePos>,
90 // Additional information used when decoding hygiene data.
91 hygiene_context: HygieneDecodeContext,
92 // Maps `DefPathHash`es to their `RawDefId`s from the *previous*
93 // compilation session. This is used as an initial 'guess' when
94 // we try to map a `DefPathHash` to its `DefId` in the current compilation
96 foreign_def_path_hashes: UnhashMap<DefPathHash, RawDefId>,
98 // The *next* compilation sessison's `foreign_def_path_hashes` - at
99 // the end of our current compilation session, this will get written
100 // out to the `foreign_def_path_hashes` field of the `Footer`, which
101 // will become `foreign_def_path_hashes` of the next compilation session.
102 // This stores any `DefPathHash` that we may need to map to a `DefId`
103 // during the next compilation session.
104 latest_foreign_def_path_hashes: Lock<UnhashMap<DefPathHash, RawDefId>>,
106 // Maps `DefPathHashes` to their corresponding `LocalDefId`s for all
107 // local items in the current compilation session. This is only populated
108 // when we are in incremental mode and have loaded a pre-existing cache
109 // from disk, since this map is only used when deserializing a `DefPathHash`
110 // from the incremental cache.
111 local_def_path_hash_to_def_id: UnhashMap<DefPathHash, LocalDefId>,
112 // Caches all lookups of `DefPathHashes`, both for local and foreign
113 // definitions. A definition from the previous compilation session
114 // may no longer exist in the current compilation session, so
115 // we use `Option<DefId>` so that we can cache a lookup failure.
116 def_path_hash_to_def_id_cache: Lock<UnhashMap<DefPathHash, Option<DefId>>>,
119 // This type is used only for serialization and deserialization.
120 #[derive(Encodable, Decodable)]
122 file_index_to_stable_id: FxHashMap<SourceFileIndex, StableSourceFileId>,
123 prev_cnums: Vec<(u32, StableCrateId)>,
124 query_result_index: EncodedQueryResultIndex,
125 diagnostics_index: EncodedQueryResultIndex,
126 // The location of all allocations.
127 interpret_alloc_index: Vec<u32>,
128 // See `OnDiskCache.syntax_contexts`
129 syntax_contexts: FxHashMap<u32, AbsoluteBytePos>,
130 // See `OnDiskCache.expn_data`
131 expn_data: FxHashMap<u32, AbsoluteBytePos>,
132 foreign_def_path_hashes: UnhashMap<DefPathHash, RawDefId>,
135 pub type EncodedQueryResultIndex = Vec<(SerializedDepNodeIndex, AbsoluteBytePos)>;
136 type EncodedDiagnosticsIndex = Vec<(SerializedDepNodeIndex, AbsoluteBytePos)>;
137 type EncodedDiagnostics = Vec<Diagnostic>;
139 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, Encodable, Decodable)]
140 struct SourceFileIndex(u32);
142 #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq, Encodable, Decodable)]
143 pub struct AbsoluteBytePos(u32);
145 impl AbsoluteBytePos {
146 fn new(pos: usize) -> AbsoluteBytePos {
147 debug_assert!(pos <= u32::MAX as usize);
148 AbsoluteBytePos(pos as u32)
151 fn to_usize(self) -> usize {
156 /// Represents a potentially invalid `DefId`. This is used during incremental
157 /// compilation to represent a `DefId` from the *previous* compilation session,
158 /// which may no longer be valid. This is used to help map a `DefPathHash`
159 /// to a `DefId` in the current compilation session.
160 #[derive(Encodable, Decodable, Copy, Clone, Debug)]
161 crate struct RawDefId {
162 // We deliberately do not use `CrateNum` and `DefIndex`
163 // here, since a crate/index from the previous compilation
164 // session may no longer exist.
169 impl<'sess> OnDiskCache<'sess> {
170 /// Creates a new `OnDiskCache` instance from the serialized data in `data`.
172 sess: &'sess Session,
175 def_path_table: &DefPathTable,
177 debug_assert!(sess.opts.incremental.is_some());
179 // Wrap in a scope so we can borrow `data`.
180 let footer: Footer = {
181 let mut decoder = opaque::Decoder::new(&data[..], start_pos);
183 // Decode the *position* of the footer, which can be found in the
184 // last 8 bytes of the file.
185 decoder.set_position(data.len() - IntEncodedWithFixedSize::ENCODED_SIZE);
186 let footer_pos = IntEncodedWithFixedSize::decode(&mut decoder)
187 .expect("error while trying to decode footer position")
190 // Decode the file footer, which contains all the lookup tables, etc.
191 decoder.set_position(footer_pos);
193 decode_tagged(&mut decoder, TAG_FILE_FOOTER)
194 .expect("error while trying to decode footer position")
198 serialized_data: data,
199 file_index_to_stable_id: footer.file_index_to_stable_id,
200 file_index_to_file: Default::default(),
201 prev_cnums: footer.prev_cnums,
202 cnum_map: OnceCell::new(),
203 source_map: sess.source_map(),
204 current_diagnostics: Default::default(),
205 query_result_index: footer.query_result_index.into_iter().collect(),
206 prev_diagnostics_index: footer.diagnostics_index.into_iter().collect(),
207 alloc_decoding_state: AllocDecodingState::new(footer.interpret_alloc_index),
208 syntax_contexts: footer.syntax_contexts,
209 expn_data: footer.expn_data,
210 hygiene_context: Default::default(),
211 foreign_def_path_hashes: footer.foreign_def_path_hashes,
212 latest_foreign_def_path_hashes: Default::default(),
213 local_def_path_hash_to_def_id: UnhashMap::from_iter(
215 .all_def_path_hashes_and_def_ids(LOCAL_CRATE)
216 .map(|(hash, def_id)| (hash, def_id.as_local().unwrap())),
218 def_path_hash_to_def_id_cache: Default::default(),
222 pub fn new_empty(source_map: &'sess SourceMap) -> Self {
224 serialized_data: Vec::new(),
225 file_index_to_stable_id: Default::default(),
226 file_index_to_file: Default::default(),
228 cnum_map: OnceCell::new(),
230 current_diagnostics: Default::default(),
231 query_result_index: Default::default(),
232 prev_diagnostics_index: Default::default(),
233 alloc_decoding_state: AllocDecodingState::new(Vec::new()),
234 syntax_contexts: FxHashMap::default(),
235 expn_data: FxHashMap::default(),
236 hygiene_context: Default::default(),
237 foreign_def_path_hashes: Default::default(),
238 latest_foreign_def_path_hashes: Default::default(),
239 local_def_path_hash_to_def_id: Default::default(),
240 def_path_hash_to_def_id_cache: Default::default(),
244 pub fn serialize<'tcx>(
247 encoder: &mut FileEncoder,
248 ) -> FileEncodeResult {
249 // Serializing the `DepGraph` should not modify it.
250 tcx.dep_graph.with_ignore(|| {
251 // Allocate `SourceFileIndex`es.
252 let (file_to_file_index, file_index_to_stable_id) = {
253 let files = tcx.sess.source_map().files();
254 let mut file_to_file_index =
255 FxHashMap::with_capacity_and_hasher(files.len(), Default::default());
256 let mut file_index_to_stable_id =
257 FxHashMap::with_capacity_and_hasher(files.len(), Default::default());
259 for (index, file) in files.iter().enumerate() {
260 let index = SourceFileIndex(index as u32);
261 let file_ptr: *const SourceFile = &**file as *const _;
262 file_to_file_index.insert(file_ptr, index);
263 file_index_to_stable_id.insert(index, StableSourceFileId::new(&file));
266 (file_to_file_index, file_index_to_stable_id)
269 // Register any dep nodes that we reused from the previous session,
270 // but didn't `DepNode::construct` in this session. This ensures
271 // that their `DefPathHash` to `RawDefId` mappings are registered
272 // in 'latest_foreign_def_path_hashes' if necessary, since that
273 // normally happens in `DepNode::construct`.
274 tcx.dep_graph.register_reused_dep_nodes(tcx);
276 // Load everything into memory so we can write it out to the on-disk
277 // cache. The vast majority of cacheable query results should already
278 // be in memory, so this should be a cheap operation.
279 // Do this *before* we clone 'latest_foreign_def_path_hashes', since
280 // loading existing queries may cause us to create new DepNodes, which
281 // may in turn end up invoking `store_foreign_def_id_hash`
282 tcx.queries.exec_cache_promotions(tcx);
284 let latest_foreign_def_path_hashes = self.latest_foreign_def_path_hashes.lock().clone();
285 let hygiene_encode_context = HygieneEncodeContext::default();
287 let mut encoder = CacheEncoder {
290 type_shorthands: Default::default(),
291 predicate_shorthands: Default::default(),
292 interpret_allocs: Default::default(),
293 source_map: CachingSourceMapView::new(tcx.sess.source_map()),
295 hygiene_context: &hygiene_encode_context,
296 latest_foreign_def_path_hashes,
299 // Encode query results.
300 let mut query_result_index = EncodedQueryResultIndex::new();
302 tcx.sess.time("encode_query_results", || -> FileEncodeResult {
303 let enc = &mut encoder;
304 let qri = &mut query_result_index;
305 tcx.queries.encode_query_results(tcx, enc, qri)
308 // Encode diagnostics.
309 let diagnostics_index: EncodedDiagnosticsIndex = self
314 |(dep_node_index, diagnostics)| -> Result<_, <FileEncoder as Encoder>::Error> {
315 let pos = AbsoluteBytePos::new(encoder.position());
316 // Let's make sure we get the expected type here.
317 let diagnostics: &EncodedDiagnostics = diagnostics;
318 let dep_node_index = SerializedDepNodeIndex::new(dep_node_index.index());
319 encoder.encode_tagged(dep_node_index, diagnostics)?;
321 Ok((dep_node_index, pos))
324 .collect::<Result<_, _>>()?;
326 let interpret_alloc_index = {
327 let mut interpret_alloc_index = Vec::new();
330 let new_n = encoder.interpret_allocs.len();
331 // If we have found new IDs, serialize those too.
336 interpret_alloc_index.reserve(new_n - n);
337 for idx in n..new_n {
338 let id = encoder.interpret_allocs[idx];
339 let pos = encoder.position() as u32;
340 interpret_alloc_index.push(pos);
341 interpret::specialized_encode_alloc_id(&mut encoder, tcx, id)?;
345 interpret_alloc_index
348 let sorted_cnums = sorted_cnums_including_local_crate(tcx);
349 let prev_cnums: Vec<_> = sorted_cnums
352 let stable_crate_id = tcx.def_path_hash(cnum.as_def_id()).stable_crate_id();
353 (cnum.as_u32(), stable_crate_id)
357 let mut syntax_contexts = FxHashMap::default();
358 let mut expn_ids = FxHashMap::default();
360 // Encode all hygiene data (`SyntaxContextData` and `ExpnData`) from the current
363 hygiene_encode_context.encode(
365 |encoder, index, ctxt_data| -> FileEncodeResult {
366 let pos = AbsoluteBytePos::new(encoder.position());
367 encoder.encode_tagged(TAG_SYNTAX_CONTEXT, ctxt_data)?;
368 syntax_contexts.insert(index, pos);
371 |encoder, index, expn_data| -> FileEncodeResult {
372 let pos = AbsoluteBytePos::new(encoder.position());
373 encoder.encode_tagged(TAG_EXPN_DATA, expn_data)?;
374 expn_ids.insert(index, pos);
379 let foreign_def_path_hashes =
380 std::mem::take(&mut encoder.latest_foreign_def_path_hashes);
382 // `Encode the file footer.
383 let footer_pos = encoder.position() as u64;
384 encoder.encode_tagged(
387 file_index_to_stable_id,
391 interpret_alloc_index,
394 foreign_def_path_hashes,
398 // Encode the position of the footer as the last 8 bytes of the
399 // file so we know where to look for it.
400 IntEncodedWithFixedSize(footer_pos).encode(encoder.encoder)?;
402 // DO NOT WRITE ANYTHING TO THE ENCODER AFTER THIS POINT! The address
403 // of the footer must be the last thing in the data stream.
407 fn sorted_cnums_including_local_crate(tcx: TyCtxt<'_>) -> Vec<CrateNum> {
408 let mut cnums = vec![LOCAL_CRATE];
409 cnums.extend_from_slice(tcx.crates());
410 cnums.sort_unstable();
411 // Just to be sure...
418 /// Loads a diagnostic emitted during the previous compilation session.
419 pub fn load_diagnostics(
422 dep_node_index: SerializedDepNodeIndex,
423 ) -> Vec<Diagnostic> {
424 let diagnostics: Option<EncodedDiagnostics> =
425 self.load_indexed(tcx, dep_node_index, &self.prev_diagnostics_index, "diagnostics");
427 diagnostics.unwrap_or_default()
430 /// Stores a diagnostic emitted during the current compilation session.
431 /// Anything stored like this will be available via `load_diagnostics` in
432 /// the next compilation session.
435 pub fn store_diagnostics(
437 dep_node_index: DepNodeIndex,
438 diagnostics: ThinVec<Diagnostic>,
440 let mut current_diagnostics = self.current_diagnostics.borrow_mut();
441 let prev = current_diagnostics.insert(dep_node_index, diagnostics.into());
442 debug_assert!(prev.is_none());
445 fn get_raw_def_id(&self, hash: &DefPathHash) -> Option<RawDefId> {
446 self.foreign_def_path_hashes.get(hash).copied()
449 fn try_remap_cnum(&self, tcx: TyCtxt<'_>, cnum: u32) -> Option<CrateNum> {
451 self.cnum_map.get_or_init(|| Self::compute_cnum_map(tcx, &self.prev_cnums[..]));
452 debug!("try_remap_cnum({}): cnum_map={:?}", cnum, cnum_map);
454 cnum_map[CrateNum::from_u32(cnum)]
457 pub(crate) fn store_foreign_def_id_hash(&self, def_id: DefId, hash: DefPathHash) {
458 // We may overwrite an existing entry, but it will have the same value,
460 self.latest_foreign_def_path_hashes
462 .insert(hash, RawDefId { krate: def_id.krate.as_u32(), index: def_id.index.as_u32() });
465 /// If the given `dep_node`'s hash still exists in the current compilation,
466 /// and its current `DefId` is foreign, calls `store_foreign_def_id` with it.
468 /// Normally, `store_foreign_def_id_hash` can be called directly by
469 /// the dependency graph when we construct a `DepNode`. However,
470 /// when we re-use a deserialized `DepNode` from the previous compilation
471 /// session, we only have the `DefPathHash` available. This method is used
472 /// to that any `DepNode` that we re-use has a `DefPathHash` -> `RawId` written
473 /// out for usage in the next compilation session.
474 pub fn register_reused_dep_node(&self, tcx: TyCtxt<'tcx>, dep_node: &DepNode) {
475 // For reused dep nodes, we only need to store the mapping if the node
476 // is one whose query key we can reconstruct from the hash. We use the
477 // mapping to aid that reconstruction in the next session. While we also
478 // use it to decode `DefId`s we encoded in the cache as `DefPathHashes`,
479 // they're already registered during `DefId` encoding.
480 if dep_node.kind.can_reconstruct_query_key() {
481 let hash = DefPathHash(dep_node.hash.into());
483 // We can't simply copy the `RawDefId` from `foreign_def_path_hashes` to
484 // `latest_foreign_def_path_hashes`, since the `RawDefId` might have
485 // changed in the current compilation session (e.g. we've added/removed crates,
486 // or added/removed definitions before/after the target definition).
487 if let Some(def_id) = self.def_path_hash_to_def_id(tcx, hash) {
488 if !def_id.is_local() {
489 self.store_foreign_def_id_hash(def_id, hash);
495 /// Returns the cached query result if there is something in the cache for
496 /// the given `SerializedDepNodeIndex`; otherwise returns `None`.
497 pub fn try_load_query_result<'tcx, T>(
500 dep_node_index: SerializedDepNodeIndex,
503 T: for<'a> Decodable<CacheDecoder<'a, 'tcx>>,
505 self.load_indexed(tcx, dep_node_index, &self.query_result_index, "query result")
508 /// Stores a diagnostic emitted during computation of an anonymous query.
509 /// Since many anonymous queries can share the same `DepNode`, we aggregate
510 /// them -- as opposed to regular queries where we assume that there is a
511 /// 1:1 relationship between query-key and `DepNode`.
514 pub fn store_diagnostics_for_anon_node(
516 dep_node_index: DepNodeIndex,
517 diagnostics: ThinVec<Diagnostic>,
519 let mut current_diagnostics = self.current_diagnostics.borrow_mut();
521 let x = current_diagnostics.entry(dep_node_index).or_default();
523 x.extend(Into::<Vec<_>>::into(diagnostics));
526 fn load_indexed<'tcx, T>(
529 dep_node_index: SerializedDepNodeIndex,
530 index: &FxHashMap<SerializedDepNodeIndex, AbsoluteBytePos>,
531 debug_tag: &'static str,
534 T: for<'a> Decodable<CacheDecoder<'a, 'tcx>>,
536 let pos = index.get(&dep_node_index).cloned()?;
538 self.with_decoder(tcx, pos, |decoder| match decode_tagged(decoder, dep_node_index) {
540 Err(e) => bug!("could not decode cached {}: {}", debug_tag, e),
544 fn with_decoder<'a, 'tcx, T, F: FnOnce(&mut CacheDecoder<'sess, 'tcx>) -> T>(
547 pos: AbsoluteBytePos,
551 T: Decodable<CacheDecoder<'a, 'tcx>>,
554 self.cnum_map.get_or_init(|| Self::compute_cnum_map(tcx, &self.prev_cnums[..]));
556 let mut decoder = CacheDecoder {
558 opaque: opaque::Decoder::new(&self.serialized_data[..], pos.to_usize()),
559 source_map: self.source_map,
561 file_index_to_file: &self.file_index_to_file,
562 file_index_to_stable_id: &self.file_index_to_stable_id,
563 alloc_decoding_session: self.alloc_decoding_state.new_decoding_session(),
564 syntax_contexts: &self.syntax_contexts,
565 expn_data: &self.expn_data,
566 hygiene_context: &self.hygiene_context,
571 // This function builds mapping from previous-session-`CrateNum` to
572 // current-session-`CrateNum`. There might be `CrateNum`s from the previous
573 // `Session` that don't occur in the current one. For these, the mapping
577 prev_cnums: &[(u32, StableCrateId)],
578 ) -> IndexVec<CrateNum, Option<CrateNum>> {
579 tcx.dep_graph.with_ignore(|| {
580 let current_cnums = tcx
584 let stable_crate_id = tcx.def_path_hash(cnum.as_def_id()).stable_crate_id();
585 (stable_crate_id, cnum)
587 .collect::<FxHashMap<_, _>>();
589 let map_size = prev_cnums.iter().map(|&(cnum, ..)| cnum).max().unwrap_or(0) + 1;
590 let mut map = IndexVec::from_elem_n(None, map_size as usize);
592 for &(prev_cnum, stable_crate_id) in prev_cnums {
593 map[CrateNum::from_u32(prev_cnum)] = current_cnums.get(&stable_crate_id).cloned();
596 map[LOCAL_CRATE] = Some(LOCAL_CRATE);
601 /// Converts a `DefPathHash` to its corresponding `DefId` in the current compilation
602 /// session, if it still exists. This is used during incremental compilation to
603 /// turn a deserialized `DefPathHash` into its current `DefId`.
604 pub(crate) fn def_path_hash_to_def_id(
609 let mut cache = self.def_path_hash_to_def_id_cache.lock();
610 match cache.entry(hash) {
611 Entry::Occupied(e) => *e.get(),
612 Entry::Vacant(e) => {
613 debug!("def_path_hash_to_def_id({:?})", hash);
614 // Check if the `DefPathHash` corresponds to a definition in the current
616 if let Some(def_id) = self.local_def_path_hash_to_def_id.get(&hash).cloned() {
617 let def_id = def_id.to_def_id();
618 e.insert(Some(def_id));
621 // This `raw_def_id` represents the `DefId` of this `DefPathHash` in
622 // the *previous* compliation session. The `DefPathHash` includes the
623 // owning crate, so if the corresponding definition still exists in the
624 // current compilation session, the crate is guaranteed to be the same
625 // (otherwise, we would compute a different `DefPathHash`).
626 let raw_def_id = self.get_raw_def_id(&hash)?;
627 debug!("def_path_hash_to_def_id({:?}): raw_def_id = {:?}", hash, raw_def_id);
628 // If the owning crate no longer exists, the corresponding definition definitely
630 let krate = self.try_remap_cnum(tcx, raw_def_id.krate)?;
631 debug!("def_path_hash_to_def_id({:?}): krate = {:?}", hash, krate);
632 // If our `DefPathHash` corresponded to a definition in the local crate,
633 // we should have either found it in `local_def_path_hash_to_def_id`, or
634 // never attempted to load it in the first place. Any query result or `DepNode`
635 // that references a local `DefId` should depend on some HIR-related `DepNode`.
636 // If a local definition is removed/modified such that its old `DefPathHash`
637 // no longer has a corresponding definition, that HIR-related `DepNode` should
638 // end up red. This should prevent us from ever calling
639 // `tcx.def_path_hash_to_def_id`, since we'll end up recomputing any
641 debug_assert_ne!(krate, LOCAL_CRATE);
642 // Try to find a definition in the current session, using the previous `DefIndex`
643 // as an initial guess.
644 let opt_def_id = tcx.cstore.def_path_hash_to_def_id(krate, raw_def_id.index, hash);
645 debug!("def_path_to_def_id({:?}): opt_def_id = {:?}", hash, opt_def_id);
646 e.insert(opt_def_id);
653 //- DECODING -------------------------------------------------------------------
655 /// A decoder that can read from the incremental compilation cache. It is similar to the one
656 /// we use for crate metadata decoding in that it can rebase spans and eventually
657 /// will also handle things that contain `Ty` instances.
658 pub struct CacheDecoder<'a, 'tcx> {
660 opaque: opaque::Decoder<'a>,
661 source_map: &'a SourceMap,
662 cnum_map: &'a IndexVec<CrateNum, Option<CrateNum>>,
663 file_index_to_file: &'a Lock<FxHashMap<SourceFileIndex, Lrc<SourceFile>>>,
664 file_index_to_stable_id: &'a FxHashMap<SourceFileIndex, StableSourceFileId>,
665 alloc_decoding_session: AllocDecodingSession<'a>,
666 syntax_contexts: &'a FxHashMap<u32, AbsoluteBytePos>,
667 expn_data: &'a FxHashMap<u32, AbsoluteBytePos>,
668 hygiene_context: &'a HygieneDecodeContext,
671 impl<'a, 'tcx> CacheDecoder<'a, 'tcx> {
672 fn file_index_to_file(&self, index: SourceFileIndex) -> Lrc<SourceFile> {
674 ref file_index_to_file,
675 ref file_index_to_stable_id,
684 let stable_id = file_index_to_stable_id[&index];
686 .source_file_by_stable_id(stable_id)
687 .expect("failed to lookup `SourceFile` in new context")
693 trait DecoderWithPosition: Decoder {
694 fn position(&self) -> usize;
697 impl<'a> DecoderWithPosition for opaque::Decoder<'a> {
698 fn position(&self) -> usize {
703 impl<'a, 'tcx> DecoderWithPosition for CacheDecoder<'a, 'tcx> {
704 fn position(&self) -> usize {
705 self.opaque.position()
709 // Decodes something that was encoded with `encode_tagged()` and verify that the
710 // tag matches and the correct amount of bytes was read.
711 fn decode_tagged<D, T, V>(decoder: &mut D, expected_tag: T) -> Result<V, D::Error>
713 T: Decodable<D> + Eq + std::fmt::Debug,
715 D: DecoderWithPosition,
717 let start_pos = decoder.position();
719 let actual_tag = T::decode(decoder)?;
720 assert_eq!(actual_tag, expected_tag);
721 let value = V::decode(decoder)?;
722 let end_pos = decoder.position();
724 let expected_len: u64 = Decodable::decode(decoder)?;
725 assert_eq!((end_pos - start_pos) as u64, expected_len);
730 impl<'a, 'tcx> TyDecoder<'tcx> for CacheDecoder<'a, 'tcx> {
731 const CLEAR_CROSS_CRATE: bool = false;
734 fn tcx(&self) -> TyCtxt<'tcx> {
739 fn position(&self) -> usize {
740 self.opaque.position()
744 fn peek_byte(&self) -> u8 {
745 self.opaque.data[self.opaque.position()]
748 fn cached_ty_for_shorthand<F>(
752 ) -> Result<Ty<'tcx>, Self::Error>
754 F: FnOnce(&mut Self) -> Result<Ty<'tcx>, Self::Error>,
756 let tcx = self.tcx();
758 let cache_key = ty::CReaderCacheKey { cnum: None, pos: shorthand };
760 if let Some(&ty) = tcx.ty_rcache.borrow().get(&cache_key) {
764 let ty = or_insert_with(self)?;
765 // This may overwrite the entry, but it should overwrite with the same value.
766 tcx.ty_rcache.borrow_mut().insert_same(cache_key, ty);
770 fn with_position<F, R>(&mut self, pos: usize, f: F) -> R
772 F: FnOnce(&mut Self) -> R,
774 debug_assert!(pos < self.opaque.data.len());
776 let new_opaque = opaque::Decoder::new(self.opaque.data, pos);
777 let old_opaque = mem::replace(&mut self.opaque, new_opaque);
779 self.opaque = old_opaque;
783 fn map_encoded_cnum_to_current(&self, cnum: CrateNum) -> CrateNum {
784 self.cnum_map[cnum].unwrap_or_else(|| bug!("could not find new `CrateNum` for {:?}", cnum))
787 fn decode_alloc_id(&mut self) -> Result<interpret::AllocId, Self::Error> {
788 let alloc_decoding_session = self.alloc_decoding_session;
789 alloc_decoding_session.decode_alloc_id(self)
793 crate::implement_ty_decoder!(CacheDecoder<'a, 'tcx>);
795 // This ensures that the `Decodable<opaque::Decoder>::decode` specialization for `Vec<u8>` is used
796 // when a `CacheDecoder` is passed to `Decodable::decode`. Unfortunately, we have to manually opt
797 // into specializations this way, given how `CacheDecoder` and the decoding traits currently work.
798 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for Vec<u8> {
799 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
800 Decodable::decode(&mut d.opaque)
804 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for SyntaxContext {
805 fn decode(decoder: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
806 let syntax_contexts = decoder.syntax_contexts;
807 rustc_span::hygiene::decode_syntax_context(decoder, decoder.hygiene_context, |this, id| {
808 // This closure is invoked if we haven't already decoded the data for the `SyntaxContext` we are deserializing.
809 // We look up the position of the associated `SyntaxData` and decode it.
810 let pos = syntax_contexts.get(&id).unwrap();
811 this.with_position(pos.to_usize(), |decoder| {
812 let data: SyntaxContextData = decode_tagged(decoder, TAG_SYNTAX_CONTEXT)?;
819 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for ExpnId {
820 fn decode(decoder: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
821 let expn_data = decoder.expn_data;
822 rustc_span::hygiene::decode_expn_id(
824 ExpnDataDecodeMode::incr_comp(decoder.hygiene_context),
826 // This closure is invoked if we haven't already decoded the data for the `ExpnId` we are deserializing.
827 // We look up the position of the associated `ExpnData` and decode it.
830 .unwrap_or_else(|| panic!("Bad index {:?} (map {:?})", index, expn_data));
832 this.with_position(pos.to_usize(), |decoder| {
833 let data: ExpnData = decode_tagged(decoder, TAG_EXPN_DATA)?;
841 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for Span {
842 fn decode(decoder: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
843 let tag: u8 = Decodable::decode(decoder)?;
845 if tag == TAG_PARTIAL_SPAN {
846 let ctxt = SyntaxContext::decode(decoder)?;
847 return Ok(DUMMY_SP.with_ctxt(ctxt));
849 debug_assert_eq!(tag, TAG_FULL_SPAN);
852 let file_lo_index = SourceFileIndex::decode(decoder)?;
853 let line_lo = usize::decode(decoder)?;
854 let col_lo = BytePos::decode(decoder)?;
855 let len = BytePos::decode(decoder)?;
856 let ctxt = SyntaxContext::decode(decoder)?;
858 let file_lo = decoder.file_index_to_file(file_lo_index);
859 let lo = file_lo.lines[line_lo - 1] + col_lo;
862 Ok(Span::new(lo, hi, ctxt))
866 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for CrateNum {
867 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
868 let cnum = CrateNum::from_u32(u32::decode(d)?);
869 Ok(d.map_encoded_cnum_to_current(cnum))
873 // This impl makes sure that we get a runtime error when we try decode a
874 // `DefIndex` that is not contained in a `DefId`. Such a case would be problematic
875 // because we would not know how to transform the `DefIndex` to the current
877 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for DefIndex {
878 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<DefIndex, String> {
879 Err(d.error("trying to decode `DefIndex` outside the context of a `DefId`"))
883 // Both the `CrateNum` and the `DefIndex` of a `DefId` can change in between two
884 // compilation sessions. We use the `DefPathHash`, which is stable across
885 // sessions, to map the old `DefId` to the new one.
886 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for DefId {
887 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
888 // Load the `DefPathHash` which is was we encoded the `DefId` as.
889 let def_path_hash = DefPathHash::decode(d)?;
891 // Using the `DefPathHash`, we can lookup the new `DefId`.
892 // Subtle: We only encode a `DefId` as part of a query result.
893 // If we get to this point, then all of the query inputs were green,
894 // which means that the definition with this hash is guaranteed to
895 // still exist in the current compilation session.
900 .def_path_hash_to_def_id(d.tcx(), def_path_hash)
905 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx FxHashSet<LocalDefId> {
906 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
907 RefDecodable::decode(d)
911 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>>
912 for &'tcx IndexVec<mir::Promoted, mir::Body<'tcx>>
914 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
915 RefDecodable::decode(d)
919 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [mir::abstract_const::Node<'tcx>] {
920 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
921 RefDecodable::decode(d)
925 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [(ty::Predicate<'tcx>, Span)] {
926 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
927 RefDecodable::decode(d)
931 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [rustc_ast::InlineAsmTemplatePiece] {
932 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
933 RefDecodable::decode(d)
937 impl<'a, 'tcx> Decodable<CacheDecoder<'a, 'tcx>> for &'tcx [Span] {
938 fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
939 RefDecodable::decode(d)
943 //- ENCODING -------------------------------------------------------------------
945 pub trait OpaqueEncoder: Encoder {
946 fn position(&self) -> usize;
949 impl OpaqueEncoder for FileEncoder {
951 fn position(&self) -> usize {
952 FileEncoder::position(self)
956 /// An encoder that can write to the incremental compilation cache.
957 pub struct CacheEncoder<'a, 'tcx, E: OpaqueEncoder> {
960 type_shorthands: FxHashMap<Ty<'tcx>, usize>,
961 predicate_shorthands: FxHashMap<ty::PredicateKind<'tcx>, usize>,
962 interpret_allocs: FxIndexSet<interpret::AllocId>,
963 source_map: CachingSourceMapView<'tcx>,
964 file_to_file_index: FxHashMap<*const SourceFile, SourceFileIndex>,
965 hygiene_context: &'a HygieneEncodeContext,
966 latest_foreign_def_path_hashes: UnhashMap<DefPathHash, RawDefId>,
969 impl<'a, 'tcx, E> CacheEncoder<'a, 'tcx, E>
971 E: 'a + OpaqueEncoder,
973 fn source_file_index(&mut self, source_file: Lrc<SourceFile>) -> SourceFileIndex {
974 self.file_to_file_index[&(&*source_file as *const SourceFile)]
977 /// Encode something with additional information that allows to do some
978 /// sanity checks when decoding the data again. This method will first
979 /// encode the specified tag, then the given value, then the number of
980 /// bytes taken up by tag and value. On decoding, we can then verify that
981 /// we get the expected tag and read the expected number of bytes.
982 fn encode_tagged<T: Encodable<Self>, V: Encodable<Self>>(
986 ) -> Result<(), E::Error> {
987 let start_pos = self.position();
992 let end_pos = self.position();
993 ((end_pos - start_pos) as u64).encode(self)
997 impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for SyntaxContext
999 E: 'a + OpaqueEncoder,
1001 fn encode(&self, s: &mut CacheEncoder<'a, 'tcx, E>) -> Result<(), E::Error> {
1002 rustc_span::hygiene::raw_encode_syntax_context(*self, s.hygiene_context, s)
1006 impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for ExpnId
1008 E: 'a + OpaqueEncoder,
1010 fn encode(&self, s: &mut CacheEncoder<'a, 'tcx, E>) -> Result<(), E::Error> {
1011 rustc_span::hygiene::raw_encode_expn_id(
1014 ExpnDataEncodeMode::IncrComp,
1020 impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for Span
1022 E: 'a + OpaqueEncoder,
1024 fn encode(&self, s: &mut CacheEncoder<'a, 'tcx, E>) -> Result<(), E::Error> {
1025 let span_data = self.data();
1026 if self.is_dummy() {
1027 TAG_PARTIAL_SPAN.encode(s)?;
1028 return span_data.ctxt.encode(s);
1031 let pos = s.source_map.byte_pos_to_line_and_col(span_data.lo);
1032 let partial_span = match &pos {
1033 Some((file_lo, _, _)) => !file_lo.contains(span_data.hi),
1038 TAG_PARTIAL_SPAN.encode(s)?;
1039 return span_data.ctxt.encode(s);
1042 let (file_lo, line_lo, col_lo) = pos.unwrap();
1044 let len = span_data.hi - span_data.lo;
1046 let source_file_index = s.source_file_index(file_lo);
1048 TAG_FULL_SPAN.encode(s)?;
1049 source_file_index.encode(s)?;
1053 span_data.ctxt.encode(s)
1057 impl<'a, 'tcx, E> TyEncoder<'tcx> for CacheEncoder<'a, 'tcx, E>
1059 E: 'a + OpaqueEncoder,
1061 const CLEAR_CROSS_CRATE: bool = false;
1063 fn position(&self) -> usize {
1064 self.encoder.position()
1066 fn type_shorthands(&mut self) -> &mut FxHashMap<Ty<'tcx>, usize> {
1067 &mut self.type_shorthands
1069 fn predicate_shorthands(&mut self) -> &mut FxHashMap<ty::PredicateKind<'tcx>, usize> {
1070 &mut self.predicate_shorthands
1072 fn encode_alloc_id(&mut self, alloc_id: &interpret::AllocId) -> Result<(), Self::Error> {
1073 let (index, _) = self.interpret_allocs.insert_full(*alloc_id);
1079 impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for DefId
1081 E: 'a + OpaqueEncoder,
1083 fn encode(&self, s: &mut CacheEncoder<'a, 'tcx, E>) -> Result<(), E::Error> {
1084 let def_path_hash = s.tcx.def_path_hash(*self);
1085 // Store additional information when we encode a foreign `DefId`,
1086 // so that we can map its `DefPathHash` back to a `DefId` in the next
1087 // compilation session.
1088 if !self.is_local() {
1089 s.latest_foreign_def_path_hashes.insert(
1091 RawDefId { krate: self.krate.as_u32(), index: self.index.as_u32() },
1094 def_path_hash.encode(s)
1098 impl<'a, 'tcx, E> Encodable<CacheEncoder<'a, 'tcx, E>> for DefIndex
1100 E: 'a + OpaqueEncoder,
1102 fn encode(&self, _: &mut CacheEncoder<'a, 'tcx, E>) -> Result<(), E::Error> {
1103 bug!("encoding `DefIndex` without context");
1107 macro_rules! encoder_methods {
1108 ($($name:ident($ty:ty);)*) => {
1110 $(fn $name(&mut self, value: $ty) -> Result<(), Self::Error> {
1111 self.encoder.$name(value)
1116 impl<'a, 'tcx, E> Encoder for CacheEncoder<'a, 'tcx, E>
1118 E: 'a + OpaqueEncoder,
1120 type Error = E::Error;
1123 fn emit_unit(&mut self) -> Result<(), Self::Error> {
1147 emit_raw_bytes(&[u8]);
1151 // This ensures that the `Encodable<opaque::FileEncoder>::encode` specialization for byte slices
1152 // is used when a `CacheEncoder` having an `opaque::FileEncoder` is passed to `Encodable::encode`.
1153 // Unfortunately, we have to manually opt into specializations this way, given how `CacheEncoder`
1154 // and the encoding traits currently work.
1155 impl<'a, 'tcx> Encodable<CacheEncoder<'a, 'tcx, FileEncoder>> for [u8] {
1156 fn encode(&self, e: &mut CacheEncoder<'a, 'tcx, FileEncoder>) -> FileEncodeResult {
1157 self.encode(e.encoder)
1161 pub fn encode_query_results<'a, 'tcx, CTX, Q>(
1163 encoder: &mut CacheEncoder<'a, 'tcx, FileEncoder>,
1164 query_result_index: &mut EncodedQueryResultIndex,
1165 ) -> FileEncodeResult
1167 CTX: QueryContext + 'tcx,
1168 Q: super::QueryDescription<CTX> + super::QueryAccessors<CTX>,
1169 Q::Value: Encodable<CacheEncoder<'a, 'tcx, FileEncoder>>,
1174 .extra_verbose_generic_activity("encode_query_results_for", std::any::type_name::<Q>());
1176 assert!(Q::query_state(tcx).all_inactive());
1177 let cache = Q::query_cache(tcx);
1178 let mut res = Ok(());
1179 cache.iter_results(&mut |key, value, dep_node| {
1183 if Q::cache_on_disk(tcx, &key, Some(value)) {
1184 let dep_node = SerializedDepNodeIndex::new(dep_node.index());
1186 // Record position of the cache entry.
1187 query_result_index.push((dep_node, AbsoluteBytePos::new(encoder.encoder.position())));
1189 // Encode the type check tables with the `SerializedDepNodeIndex`
1191 match encoder.encode_tagged(dep_node, value) {