1 // Decoding metadata from a single crate's metadata
3 use crate::creader::CrateMetadataRef;
4 use crate::rmeta::table::{FixedSizeEncoding, Table};
8 use rustc_attr as attr;
9 use rustc_data_structures::captures::Captures;
10 use rustc_data_structures::fx::FxHashMap;
11 use rustc_data_structures::svh::Svh;
12 use rustc_data_structures::sync::{Lock, LockGuard, Lrc, OnceCell};
13 use rustc_data_structures::unhash::UnhashMap;
14 use rustc_expand::base::{SyntaxExtension, SyntaxExtensionKind};
15 use rustc_expand::proc_macro::{AttrProcMacro, BangProcMacro, ProcMacroDerive};
17 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
18 use rustc_hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
19 use rustc_hir::definitions::{DefKey, DefPath, DefPathData, DefPathHash};
20 use rustc_hir::diagnostic_items::DiagnosticItems;
21 use rustc_hir::lang_items;
22 use rustc_index::vec::{Idx, IndexVec};
23 use rustc_middle::arena::ArenaAllocatable;
24 use rustc_middle::metadata::ModChild;
25 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
26 use rustc_middle::middle::stability::DeprecationEntry;
27 use rustc_middle::mir::interpret::{AllocDecodingSession, AllocDecodingState};
28 use rustc_middle::thir;
29 use rustc_middle::ty::codec::TyDecoder;
30 use rustc_middle::ty::fast_reject::SimplifiedType;
31 use rustc_middle::ty::{self, Ty, TyCtxt, Visibility};
32 use rustc_serialize::{opaque, Decodable, Decoder};
33 use rustc_session::cstore::{
34 CrateSource, ExternCrate, ForeignModule, LinkagePreference, NativeLib,
36 use rustc_session::Session;
37 use rustc_span::hygiene::{ExpnIndex, MacroKind};
38 use rustc_span::source_map::{respan, Spanned};
39 use rustc_span::symbol::{sym, Ident, Symbol};
40 use rustc_span::{self, BytePos, ExpnId, Pos, Span, SyntaxContext, DUMMY_SP};
42 use proc_macro::bridge::client::ProcMacro;
45 use std::num::NonZeroUsize;
49 pub(super) use cstore_impl::provide;
50 pub use cstore_impl::provide_extern;
51 use rustc_span::hygiene::HygieneDecodeContext;
55 /// A reference to the raw binary version of crate metadata.
56 /// A `MetadataBlob` internally is just a reference counted pointer to
57 /// the actual data, so cloning it is cheap.
59 crate struct MetadataBlob(Lrc<MetadataRef>);
61 // This is needed so we can create an OwningRef into the blob.
62 // The data behind a `MetadataBlob` has a stable address because it is
63 // contained within an Rc/Arc.
64 unsafe impl rustc_data_structures::owning_ref::StableAddress for MetadataBlob {}
66 // This is needed so we can create an OwningRef into the blob.
67 impl std::ops::Deref for MetadataBlob {
71 fn deref(&self) -> &[u8] {
76 // A map from external crate numbers (as decoded from some crate file) to
77 // local crate numbers (as generated during this session). Each external
78 // crate may refer to types in other external crates, and each has their
80 crate type CrateNumMap = IndexVec<CrateNum, CrateNum>;
82 crate struct CrateMetadata {
83 /// The primary crate data - binary metadata blob.
86 // --- Some data pre-decoded from the metadata blob, usually for performance ---
87 /// Properties of the whole crate.
88 /// NOTE(eddyb) we pass `'static` to a `'tcx` parameter because this
89 /// lifetime is only used behind `Lazy`, and therefore acts like a
90 /// universal (`for<'tcx>`), that is paired up with whichever `TyCtxt`
91 /// is being used to decode those values.
92 root: CrateRoot<'static>,
94 /// FIXME: Used only from queries and can use query cache,
95 /// so pre-decoding can probably be avoided.
96 trait_impls: FxHashMap<(u32, DefIndex), Lazy<[(DefIndex, Option<SimplifiedType>)]>>,
97 /// Proc macro descriptions for this crate, if it's a proc macro crate.
98 raw_proc_macros: Option<&'static [ProcMacro]>,
99 /// Source maps for code from the crate.
100 source_map_import_info: OnceCell<Vec<ImportedSourceFile>>,
101 /// For every definition in this crate, maps its `DefPathHash` to its `DefIndex`.
102 def_path_hash_map: DefPathHashMapRef<'static>,
103 /// Likewise for ExpnHash.
104 expn_hash_map: OnceCell<UnhashMap<ExpnHash, ExpnIndex>>,
105 /// Used for decoding interpret::AllocIds in a cached & thread-safe manner.
106 alloc_decoding_state: AllocDecodingState,
107 /// Caches decoded `DefKey`s.
108 def_key_cache: Lock<FxHashMap<DefIndex, DefKey>>,
109 /// Caches decoded `DefPathHash`es.
110 def_path_hash_cache: Lock<FxHashMap<DefIndex, DefPathHash>>,
112 // --- Other significant crate properties ---
113 /// ID of this crate, from the current compilation session's point of view.
115 /// Maps crate IDs as they are were seen from this crate's compilation sessions into
116 /// IDs as they are seen from the current compilation session.
117 cnum_map: CrateNumMap,
118 /// Same ID set as `cnum_map` plus maybe some injected crates like panic runtime.
119 dependencies: Lock<Vec<CrateNum>>,
120 /// How to link (or not link) this crate to the currently compiled crate.
121 dep_kind: Lock<CrateDepKind>,
122 /// Filesystem location of this crate.
123 source: Lrc<CrateSource>,
124 /// Whether or not this crate should be consider a private dependency
125 /// for purposes of the 'exported_private_dependencies' lint
127 /// The hash for the host proc macro. Used to support `-Z dual-proc-macro`.
128 host_hash: Option<Svh>,
130 /// Additional data used for decoding `HygieneData` (e.g. `SyntaxContext`
132 /// Note that we store a `HygieneDecodeContext` for each `CrateMetadat`. This is
133 /// because `SyntaxContext` ids are not globally unique, so we need
134 /// to track which ids we've decoded on a per-crate basis.
135 hygiene_context: HygieneDecodeContext,
137 // --- Data used only for improving diagnostics ---
138 /// Information about the `extern crate` item or path that caused this crate to be loaded.
139 /// If this is `None`, then the crate was injected (e.g., by the allocator).
140 extern_crate: Lock<Option<ExternCrate>>,
143 /// Holds information about a rustc_span::SourceFile imported from another crate.
144 /// See `imported_source_files()` for more information.
145 struct ImportedSourceFile {
146 /// This SourceFile's byte-offset within the source_map of its original crate
147 original_start_pos: rustc_span::BytePos,
148 /// The end of this SourceFile within the source_map of its original crate
149 original_end_pos: rustc_span::BytePos,
150 /// The imported SourceFile's representation within the local source_map
151 translated_source_file: Lrc<rustc_span::SourceFile>,
154 pub(super) struct DecodeContext<'a, 'tcx> {
155 opaque: opaque::Decoder<'a>,
156 cdata: Option<CrateMetadataRef<'a>>,
157 blob: &'a MetadataBlob,
158 sess: Option<&'tcx Session>,
159 tcx: Option<TyCtxt<'tcx>>,
161 // Cache the last used source_file for translating spans as an optimization.
162 last_source_file_index: usize,
164 lazy_state: LazyState,
166 // Used for decoding interpret::AllocIds in a cached & thread-safe manner.
167 alloc_decoding_session: Option<AllocDecodingSession<'a>>,
170 /// Abstract over the various ways one can create metadata decoders.
171 pub(super) trait Metadata<'a, 'tcx>: Copy {
172 fn blob(self) -> &'a MetadataBlob;
174 fn cdata(self) -> Option<CrateMetadataRef<'a>> {
177 fn sess(self) -> Option<&'tcx Session> {
180 fn tcx(self) -> Option<TyCtxt<'tcx>> {
184 fn decoder(self, pos: usize) -> DecodeContext<'a, 'tcx> {
185 let tcx = self.tcx();
187 opaque: opaque::Decoder::new(self.blob(), pos),
190 sess: self.sess().or(tcx.map(|tcx| tcx.sess)),
192 last_source_file_index: 0,
193 lazy_state: LazyState::NoNode,
194 alloc_decoding_session: self
196 .map(|cdata| cdata.cdata.alloc_decoding_state.new_decoding_session()),
201 impl<'a, 'tcx> Metadata<'a, 'tcx> for &'a MetadataBlob {
203 fn blob(self) -> &'a MetadataBlob {
208 impl<'a, 'tcx> Metadata<'a, 'tcx> for (&'a MetadataBlob, &'tcx Session) {
210 fn blob(self) -> &'a MetadataBlob {
215 fn sess(self) -> Option<&'tcx Session> {
216 let (_, sess) = self;
221 impl<'a, 'tcx> Metadata<'a, 'tcx> for CrateMetadataRef<'a> {
223 fn blob(self) -> &'a MetadataBlob {
227 fn cdata(self) -> Option<CrateMetadataRef<'a>> {
232 impl<'a, 'tcx> Metadata<'a, 'tcx> for (CrateMetadataRef<'a>, &'tcx Session) {
234 fn blob(self) -> &'a MetadataBlob {
238 fn cdata(self) -> Option<CrateMetadataRef<'a>> {
242 fn sess(self) -> Option<&'tcx Session> {
247 impl<'a, 'tcx> Metadata<'a, 'tcx> for (CrateMetadataRef<'a>, TyCtxt<'tcx>) {
249 fn blob(self) -> &'a MetadataBlob {
253 fn cdata(self) -> Option<CrateMetadataRef<'a>> {
257 fn tcx(self) -> Option<TyCtxt<'tcx>> {
262 impl<'a, 'tcx, T: Decodable<DecodeContext<'a, 'tcx>>> Lazy<T> {
263 fn decode<M: Metadata<'a, 'tcx>>(self, metadata: M) -> T {
264 let mut dcx = metadata.decoder(self.position.get());
265 dcx.lazy_state = LazyState::NodeStart(self.position);
270 impl<'a: 'x, 'tcx: 'x, 'x, T: Decodable<DecodeContext<'a, 'tcx>>> Lazy<[T]> {
271 fn decode<M: Metadata<'a, 'tcx>>(
274 ) -> impl ExactSizeIterator<Item = T> + Captures<'a> + Captures<'tcx> + 'x {
275 let mut dcx = metadata.decoder(self.position.get());
276 dcx.lazy_state = LazyState::NodeStart(self.position);
277 (0..self.meta).map(move |_| T::decode(&mut dcx))
281 trait LazyQueryDecodable<'a, 'tcx, T> {
284 cdata: CrateMetadataRef<'a>,
286 err: impl FnOnce() -> !,
290 impl<'a, 'tcx, T> LazyQueryDecodable<'a, 'tcx, T> for Option<Lazy<T>>
292 T: Decodable<DecodeContext<'a, 'tcx>>,
296 cdata: CrateMetadataRef<'a>,
298 err: impl FnOnce() -> !,
300 if let Some(l) = self { l.decode((cdata, tcx)) } else { err() }
304 impl<'a, 'tcx, T> LazyQueryDecodable<'a, 'tcx, &'tcx T> for Option<Lazy<T>>
306 T: Decodable<DecodeContext<'a, 'tcx>>,
307 T: ArenaAllocatable<'tcx>,
311 cdata: CrateMetadataRef<'a>,
313 err: impl FnOnce() -> !,
315 if let Some(l) = self { tcx.arena.alloc(l.decode((cdata, tcx))) } else { err() }
319 impl<'a, 'tcx, T> LazyQueryDecodable<'a, 'tcx, Option<T>> for Option<Lazy<T>>
321 T: Decodable<DecodeContext<'a, 'tcx>>,
325 cdata: CrateMetadataRef<'a>,
327 _err: impl FnOnce() -> !,
329 self.map(|l| l.decode((cdata, tcx)))
333 impl<'a, 'tcx, T, E> LazyQueryDecodable<'a, 'tcx, Result<Option<T>, E>> for Option<Lazy<T>>
335 T: Decodable<DecodeContext<'a, 'tcx>>,
339 cdata: CrateMetadataRef<'a>,
341 _err: impl FnOnce() -> !,
342 ) -> Result<Option<T>, E> {
343 Ok(self.map(|l| l.decode((cdata, tcx))))
347 impl<'a, 'tcx, T> LazyQueryDecodable<'a, 'tcx, &'tcx [T]> for Option<Lazy<[T], usize>>
349 T: Decodable<DecodeContext<'a, 'tcx>> + Copy,
353 cdata: CrateMetadataRef<'a>,
355 _err: impl FnOnce() -> !,
357 if let Some(l) = self { tcx.arena.alloc_from_iter(l.decode((cdata, tcx))) } else { &[] }
361 impl<'a, 'tcx> LazyQueryDecodable<'a, 'tcx, Option<DeprecationEntry>>
362 for Option<Lazy<attr::Deprecation>>
366 cdata: CrateMetadataRef<'a>,
368 _err: impl FnOnce() -> !,
369 ) -> Option<DeprecationEntry> {
370 self.map(|l| l.decode((cdata, tcx))).map(DeprecationEntry::external)
374 impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
376 fn tcx(&self) -> TyCtxt<'tcx> {
377 debug_assert!(self.tcx.is_some(), "missing TyCtxt in DecodeContext");
382 pub fn blob(&self) -> &'a MetadataBlob {
387 pub fn cdata(&self) -> CrateMetadataRef<'a> {
388 debug_assert!(self.cdata.is_some(), "missing CrateMetadata in DecodeContext");
392 fn map_encoded_cnum_to_current(&self, cnum: CrateNum) -> CrateNum {
393 if cnum == LOCAL_CRATE { self.cdata().cnum } else { self.cdata().cnum_map[cnum] }
396 fn read_lazy_with_meta<T: ?Sized + LazyMeta>(&mut self, meta: T::Meta) -> Lazy<T> {
397 let distance = self.read_usize();
398 let position = match self.lazy_state {
399 LazyState::NoNode => bug!("read_lazy_with_meta: outside of a metadata node"),
400 LazyState::NodeStart(start) => {
401 let start = start.get();
402 assert!(distance <= start);
405 LazyState::Previous(last_pos) => last_pos.get() + distance,
407 self.lazy_state = LazyState::Previous(NonZeroUsize::new(position).unwrap());
408 Lazy::from_position_and_meta(NonZeroUsize::new(position).unwrap(), meta)
412 pub fn read_raw_bytes(&mut self, len: usize) -> &'a [u8] {
413 self.opaque.read_raw_bytes(len)
417 impl<'a, 'tcx> TyDecoder<'tcx> for DecodeContext<'a, 'tcx> {
418 const CLEAR_CROSS_CRATE: bool = true;
421 fn tcx(&self) -> TyCtxt<'tcx> {
422 self.tcx.expect("missing TyCtxt in DecodeContext")
426 fn peek_byte(&self) -> u8 {
427 self.opaque.data[self.opaque.position()]
431 fn position(&self) -> usize {
432 self.opaque.position()
435 fn cached_ty_for_shorthand<F>(&mut self, shorthand: usize, or_insert_with: F) -> Ty<'tcx>
437 F: FnOnce(&mut Self) -> Ty<'tcx>,
439 let tcx = self.tcx();
441 let key = ty::CReaderCacheKey { cnum: Some(self.cdata().cnum), pos: shorthand };
443 if let Some(&ty) = tcx.ty_rcache.borrow().get(&key) {
447 let ty = or_insert_with(self);
448 tcx.ty_rcache.borrow_mut().insert(key, ty);
452 fn with_position<F, R>(&mut self, pos: usize, f: F) -> R
454 F: FnOnce(&mut Self) -> R,
456 let new_opaque = opaque::Decoder::new(self.opaque.data, pos);
457 let old_opaque = mem::replace(&mut self.opaque, new_opaque);
458 let old_state = mem::replace(&mut self.lazy_state, LazyState::NoNode);
460 self.opaque = old_opaque;
461 self.lazy_state = old_state;
465 fn decode_alloc_id(&mut self) -> rustc_middle::mir::interpret::AllocId {
466 if let Some(alloc_decoding_session) = self.alloc_decoding_session {
467 alloc_decoding_session.decode_alloc_id(self)
469 bug!("Attempting to decode interpret::AllocId without CrateMetadata")
474 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for CrateNum {
475 fn decode(d: &mut DecodeContext<'a, 'tcx>) -> CrateNum {
476 let cnum = CrateNum::from_u32(d.read_u32());
477 d.map_encoded_cnum_to_current(cnum)
481 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for DefIndex {
482 fn decode(d: &mut DecodeContext<'a, 'tcx>) -> DefIndex {
483 DefIndex::from_u32(d.read_u32())
487 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ExpnIndex {
488 fn decode(d: &mut DecodeContext<'a, 'tcx>) -> ExpnIndex {
489 ExpnIndex::from_u32(d.read_u32())
493 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for SyntaxContext {
494 fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> SyntaxContext {
495 let cdata = decoder.cdata();
496 let sess = decoder.sess.unwrap();
497 let cname = cdata.root.name;
498 rustc_span::hygiene::decode_syntax_context(decoder, &cdata.hygiene_context, |_, id| {
499 debug!("SpecializedDecoder<SyntaxContext>: decoding {}", id);
504 .unwrap_or_else(|| panic!("Missing SyntaxContext {:?} for crate {:?}", id, cname))
505 .decode((cdata, sess))
510 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ExpnId {
511 fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> ExpnId {
512 let local_cdata = decoder.cdata();
513 let sess = decoder.sess.unwrap();
515 let cnum = CrateNum::decode(decoder);
516 let index = u32::decode(decoder);
518 let expn_id = rustc_span::hygiene::decode_expn_id(cnum, index, |expn_id| {
519 let ExpnId { krate: cnum, local_id: index } = expn_id;
520 // Lookup local `ExpnData`s in our own crate data. Foreign `ExpnData`s
521 // are stored in the owning crate, to avoid duplication.
522 debug_assert_ne!(cnum, LOCAL_CRATE);
523 let crate_data = if cnum == local_cdata.cnum {
526 local_cdata.cstore.get_crate_data(cnum)
528 let expn_data = crate_data
531 .get(crate_data, index)
533 .decode((crate_data, sess));
534 let expn_hash = crate_data
537 .get(crate_data, index)
539 .decode((crate_data, sess));
540 (expn_data, expn_hash)
546 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Span {
547 fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> Span {
548 let ctxt = SyntaxContext::decode(decoder);
549 let tag = u8::decode(decoder);
551 if tag == TAG_PARTIAL_SPAN {
552 return DUMMY_SP.with_ctxt(ctxt);
555 debug_assert!(tag == TAG_VALID_SPAN_LOCAL || tag == TAG_VALID_SPAN_FOREIGN);
557 let lo = BytePos::decode(decoder);
558 let len = BytePos::decode(decoder);
561 let Some(sess) = decoder.sess else {
562 bug!("Cannot decode Span without Session.")
565 // There are two possibilities here:
566 // 1. This is a 'local span', which is located inside a `SourceFile`
567 // that came from this crate. In this case, we use the source map data
568 // encoded in this crate. This branch should be taken nearly all of the time.
569 // 2. This is a 'foreign span', which is located inside a `SourceFile`
570 // that came from a *different* crate (some crate upstream of the one
571 // whose metadata we're looking at). For example, consider this dependency graph:
575 // Suppose that we're currently compiling crate A, and start deserializing
576 // metadata from crate B. When we deserialize a Span from crate B's metadata,
577 // there are two posibilites:
579 // 1. The span references a file from crate B. This makes it a 'local' span,
580 // which means that we can use crate B's serialized source map information.
581 // 2. The span references a file from crate C. This makes it a 'foreign' span,
582 // which means we need to use Crate *C* (not crate B) to determine the source
583 // map information. We only record source map information for a file in the
584 // crate that 'owns' it, so deserializing a Span may require us to look at
585 // a transitive dependency.
587 // When we encode a foreign span, we adjust its 'lo' and 'high' values
588 // to be based on the *foreign* crate (e.g. crate C), not the crate
589 // we are writing metadata for (e.g. crate B). This allows us to
590 // treat the 'local' and 'foreign' cases almost identically during deserialization:
591 // we can call `imported_source_files` for the proper crate, and binary search
592 // through the returned slice using our span.
593 let imported_source_files = if tag == TAG_VALID_SPAN_LOCAL {
594 decoder.cdata().imported_source_files(sess)
596 // When we encode a proc-macro crate, all `Span`s should be encoded
597 // with `TAG_VALID_SPAN_LOCAL`
598 if decoder.cdata().root.is_proc_macro_crate() {
599 // Decode `CrateNum` as u32 - using `CrateNum::decode` will ICE
600 // since we don't have `cnum_map` populated.
601 let cnum = u32::decode(decoder);
603 "Decoding of crate {:?} tried to access proc-macro dep {:?}",
604 decoder.cdata().root.name,
608 // tag is TAG_VALID_SPAN_FOREIGN, checked by `debug_assert` above
609 let cnum = CrateNum::decode(decoder);
611 "SpecializedDecoder<Span>::specialized_decode: loading source files from cnum {:?}",
615 // Decoding 'foreign' spans should be rare enough that it's
616 // not worth it to maintain a per-CrateNum cache for `last_source_file_index`.
617 // We just set it to 0, to ensure that we don't try to access something out
618 // of bounds for our initial 'guess'
619 decoder.last_source_file_index = 0;
621 let foreign_data = decoder.cdata().cstore.get_crate_data(cnum);
622 foreign_data.imported_source_files(sess)
626 // Optimize for the case that most spans within a translated item
627 // originate from the same source_file.
628 let last_source_file = &imported_source_files[decoder.last_source_file_index];
630 if lo >= last_source_file.original_start_pos && lo <= last_source_file.original_end_pos
634 let index = imported_source_files
635 .binary_search_by_key(&lo, |source_file| source_file.original_start_pos)
636 .unwrap_or_else(|index| index - 1);
638 // Don't try to cache the index for foreign spans,
639 // as this would require a map from CrateNums to indices
640 if tag == TAG_VALID_SPAN_LOCAL {
641 decoder.last_source_file_index = index;
643 &imported_source_files[index]
647 // Make sure our binary search above is correct.
649 lo >= source_file.original_start_pos && lo <= source_file.original_end_pos,
650 "Bad binary search: lo={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
652 source_file.original_start_pos,
653 source_file.original_end_pos
656 // Make sure we correctly filtered out invalid spans during encoding
658 hi >= source_file.original_start_pos && hi <= source_file.original_end_pos,
659 "Bad binary search: hi={:?} source_file.original_start_pos={:?} source_file.original_end_pos={:?}",
661 source_file.original_start_pos,
662 source_file.original_end_pos
666 (lo + source_file.translated_source_file.start_pos) - source_file.original_start_pos;
668 (hi + source_file.translated_source_file.start_pos) - source_file.original_start_pos;
670 // Do not try to decode parent for foreign spans.
671 Span::new(lo, hi, ctxt, None)
675 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [thir::abstract_const::Node<'tcx>] {
676 fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Self {
677 ty::codec::RefDecodable::decode(d)
681 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [(ty::Predicate<'tcx>, Span)] {
682 fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Self {
683 ty::codec::RefDecodable::decode(d)
687 impl<'a, 'tcx, T: Decodable<DecodeContext<'a, 'tcx>>> Decodable<DecodeContext<'a, 'tcx>>
690 fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> Self {
691 decoder.read_lazy_with_meta(())
695 impl<'a, 'tcx, T: Decodable<DecodeContext<'a, 'tcx>>> Decodable<DecodeContext<'a, 'tcx>>
698 fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> Self {
699 let len = decoder.read_usize();
700 if len == 0 { Lazy::empty() } else { decoder.read_lazy_with_meta(len) }
704 impl<'a, 'tcx, I: Idx, T: Decodable<DecodeContext<'a, 'tcx>>> Decodable<DecodeContext<'a, 'tcx>>
705 for Lazy<Table<I, T>>
707 Option<T>: FixedSizeEncoding,
709 fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> Self {
710 let len = decoder.read_usize();
711 decoder.read_lazy_with_meta(len)
715 implement_ty_decoder!(DecodeContext<'a, 'tcx>);
717 impl<'tcx> MetadataBlob {
718 crate fn new(metadata_ref: MetadataRef) -> MetadataBlob {
719 MetadataBlob(Lrc::new(metadata_ref))
722 crate fn is_compatible(&self) -> bool {
723 self.blob().starts_with(METADATA_HEADER)
726 crate fn get_rustc_version(&self) -> String {
727 Lazy::<String>::from_position(NonZeroUsize::new(METADATA_HEADER.len() + 4).unwrap())
731 crate fn get_root(&self) -> CrateRoot<'tcx> {
732 let slice = &self.blob()[..];
733 let offset = METADATA_HEADER.len();
734 let pos = (((slice[offset + 0] as u32) << 24)
735 | ((slice[offset + 1] as u32) << 16)
736 | ((slice[offset + 2] as u32) << 8)
737 | ((slice[offset + 3] as u32) << 0)) as usize;
738 Lazy::<CrateRoot<'tcx>>::from_position(NonZeroUsize::new(pos).unwrap()).decode(self)
741 crate fn list_crate_metadata(&self, out: &mut dyn io::Write) -> io::Result<()> {
742 let root = self.get_root();
743 writeln!(out, "Crate info:")?;
744 writeln!(out, "name {}{}", root.name, root.extra_filename)?;
745 writeln!(out, "hash {} stable_crate_id {:?}", root.hash, root.stable_crate_id)?;
746 writeln!(out, "proc_macro {:?}", root.proc_macro_data.is_some())?;
747 writeln!(out, "=External Dependencies=")?;
748 for (i, dep) in root.crate_deps.decode(self).enumerate() {
751 "{} {}{} hash {} host_hash {:?} kind {:?}",
766 crate fn is_proc_macro_crate(&self) -> bool {
767 self.proc_macro_data.is_some()
770 crate fn name(&self) -> Symbol {
774 crate fn hash(&self) -> Svh {
778 crate fn stable_crate_id(&self) -> StableCrateId {
782 crate fn triple(&self) -> &TargetTriple {
786 crate fn decode_crate_deps<'a>(
788 metadata: &'a MetadataBlob,
789 ) -> impl ExactSizeIterator<Item = CrateDep> + Captures<'a> {
790 self.crate_deps.decode(metadata)
794 impl<'a, 'tcx> CrateMetadataRef<'a> {
795 fn raw_proc_macro(self, id: DefIndex) -> &'a ProcMacro {
796 // DefIndex's in root.proc_macro_data have a one-to-one correspondence
797 // with items in 'raw_proc_macros'.
805 .position(|i| i == id)
807 &self.raw_proc_macros.unwrap()[pos]
810 fn opt_item_name(self, item_index: DefIndex) -> Option<Symbol> {
811 self.def_key(item_index).disambiguated_data.data.get_opt_name()
814 fn item_name(self, item_index: DefIndex) -> Symbol {
815 self.opt_item_name(item_index).expect("no encoded ident for item")
818 fn opt_item_ident(self, item_index: DefIndex, sess: &Session) -> Option<Ident> {
819 let name = self.opt_item_name(item_index)?;
820 let span = match self.root.tables.def_ident_span.get(self, item_index) {
821 Some(lazy_span) => lazy_span.decode((self, sess)),
823 // FIXME: this weird case of a name with no span is specific to `extern crate`
824 // items, which are supposed to be treated like `use` items and only be encoded
825 // to metadata as `Export`s, return `None` because that's what all the callers
826 // expect in this case.
827 assert_eq!(self.def_kind(item_index), DefKind::ExternCrate);
831 Some(Ident::new(name, span))
834 fn item_ident(self, item_index: DefIndex, sess: &Session) -> Ident {
835 self.opt_item_ident(item_index, sess).expect("no encoded ident for item")
838 fn maybe_kind(self, item_id: DefIndex) -> Option<EntryKind> {
839 self.root.tables.kind.get(self, item_id).map(|k| k.decode(self))
842 fn kind(self, item_id: DefIndex) -> EntryKind {
843 self.maybe_kind(item_id).unwrap_or_else(|| {
845 "CrateMetadata::kind({:?}): id not found, in crate {:?} with number {}",
853 fn def_kind(self, item_id: DefIndex) -> DefKind {
854 self.root.tables.opt_def_kind.get(self, item_id).map(|k| k.decode(self)).unwrap_or_else(
857 "CrateMetadata::def_kind({:?}): id not found, in crate {:?} with number {}",
866 fn get_span(self, index: DefIndex, sess: &Session) -> Span {
871 .unwrap_or_else(|| panic!("Missing span for {:?}", index))
872 .decode((self, sess))
875 fn load_proc_macro(self, id: DefIndex, sess: &Session) -> SyntaxExtension {
876 let (name, kind, helper_attrs) = match *self.raw_proc_macro(id) {
877 ProcMacro::CustomDerive { trait_name, attributes, client } => {
879 attributes.iter().cloned().map(Symbol::intern).collect::<Vec<_>>();
882 SyntaxExtensionKind::Derive(Box::new(ProcMacroDerive { client })),
886 ProcMacro::Attr { name, client } => {
887 (name, SyntaxExtensionKind::Attr(Box::new(AttrProcMacro { client })), Vec::new())
889 ProcMacro::Bang { name, client } => {
890 (name, SyntaxExtensionKind::Bang(Box::new(BangProcMacro { client })), Vec::new())
894 let attrs: Vec<_> = self.get_item_attrs(id, sess).collect();
895 SyntaxExtension::new(
898 self.get_span(id, sess),
901 Symbol::intern(name),
906 fn get_trait_def(self, item_id: DefIndex, sess: &Session) -> ty::TraitDef {
907 match self.kind(item_id) {
908 EntryKind::Trait(data) => {
909 let data = data.decode((self, sess));
911 self.local_def_id(item_id),
916 data.skip_array_during_method_dispatch,
917 data.specialization_kind,
918 self.def_path_hash(item_id),
919 data.must_implement_one_of,
922 EntryKind::TraitAlias => ty::TraitDef::new(
923 self.local_def_id(item_id),
924 hir::Unsafety::Normal,
929 ty::trait_def::TraitSpecializationKind::None,
930 self.def_path_hash(item_id),
933 _ => bug!("def-index does not refer to trait or trait alias"),
937 fn get_variant(self, kind: &EntryKind, index: DefIndex, parent_did: DefId) -> ty::VariantDef {
938 let data = match kind {
939 EntryKind::Variant(data) | EntryKind::Struct(data, _) | EntryKind::Union(data, _) => {
945 let adt_kind = match kind {
946 EntryKind::Variant(_) => ty::AdtKind::Enum,
947 EntryKind::Struct(..) => ty::AdtKind::Struct,
948 EntryKind::Union(..) => ty::AdtKind::Union,
953 if adt_kind == ty::AdtKind::Enum { Some(self.local_def_id(index)) } else { None };
954 let ctor_did = data.ctor.map(|index| self.local_def_id(index));
957 self.item_name(index),
965 .unwrap_or_else(Lazy::empty)
967 .map(|index| ty::FieldDef {
968 did: self.local_def_id(index),
969 name: self.item_name(index),
970 vis: self.get_visibility(index),
977 data.is_non_exhaustive,
981 fn get_adt_def(self, item_id: DefIndex, tcx: TyCtxt<'tcx>) -> &'tcx ty::AdtDef {
982 let kind = self.kind(item_id);
983 let did = self.local_def_id(item_id);
985 let (adt_kind, repr) = match kind {
986 EntryKind::Enum(repr) => (ty::AdtKind::Enum, repr),
987 EntryKind::Struct(_, repr) => (ty::AdtKind::Struct, repr),
988 EntryKind::Union(_, repr) => (ty::AdtKind::Union, repr),
989 _ => bug!("get_adt_def called on a non-ADT {:?}", did),
992 let variants = if let ty::AdtKind::Enum = adt_kind {
997 .unwrap_or_else(Lazy::empty)
999 .map(|index| self.get_variant(&self.kind(index), index, did))
1002 std::iter::once(self.get_variant(&kind, item_id, did)).collect()
1005 tcx.alloc_adt_def(did, adt_kind, variants, repr)
1008 fn get_generics(self, item_id: DefIndex, sess: &Session) -> ty::Generics {
1009 self.root.tables.generics_of.get(self, item_id).unwrap().decode((self, sess))
1012 fn get_visibility(self, id: DefIndex) -> ty::Visibility {
1013 self.root.tables.visibility.get(self, id).unwrap().decode(self)
1016 fn get_trait_item_def_id(self, id: DefIndex) -> Option<DefId> {
1017 self.root.tables.trait_item_def_id.get(self, id).map(|d| d.decode(self))
1020 fn get_expn_that_defined(self, id: DefIndex, sess: &Session) -> ExpnId {
1021 self.root.tables.expn_that_defined.get(self, id).unwrap().decode((self, sess))
1024 /// Iterates over all the stability attributes in the given crate.
1025 fn get_lib_features(self, tcx: TyCtxt<'tcx>) -> &'tcx [(Symbol, Option<Symbol>)] {
1026 tcx.arena.alloc_from_iter(self.root.lib_features.decode(self))
1029 /// Iterates over the language items in the given crate.
1030 fn get_lang_items(self) -> impl Iterator<Item = (DefId, usize)> + 'a {
1034 .map(move |(def_index, index)| (self.local_def_id(def_index), index))
1037 /// Iterates over the diagnostic items in the given crate.
1038 fn get_diagnostic_items(self) -> DiagnosticItems {
1039 let mut id_to_name = FxHashMap::default();
1040 let name_to_id = self
1044 .map(|(name, def_index)| {
1045 let id = self.local_def_id(def_index);
1046 id_to_name.insert(id, name);
1050 DiagnosticItems { id_to_name, name_to_id }
1053 /// Iterates over all named children of the given module,
1054 /// including both proper items and reexports.
1055 /// Module here is understood in name resolution sense - it can be a `mod` item,
1056 /// or a crate root, or an enum, or a trait.
1057 fn for_each_module_child(
1060 mut callback: impl FnMut(ModChild),
1063 if let Some(data) = &self.root.proc_macro_data {
1064 // If we are loading as a proc macro, we want to return
1065 // the view of this crate as a proc macro crate.
1066 if id == CRATE_DEF_INDEX {
1067 for def_index in data.macros.decode(self) {
1068 let raw_macro = self.raw_proc_macro(def_index);
1070 DefKind::Macro(macro_kind(raw_macro)),
1071 self.local_def_id(def_index),
1073 let ident = self.item_ident(def_index, sess);
1077 vis: ty::Visibility::Public,
1085 // Iterate over all children.
1086 if let Some(children) = self.root.tables.children.get(self, id) {
1087 for child_index in children.decode((self, sess)) {
1088 if let Some(ident) = self.opt_item_ident(child_index, sess) {
1089 let kind = self.def_kind(child_index);
1090 if matches!(kind, DefKind::Macro(..)) {
1091 // FIXME: Macros are currently encoded twice, once as items and once as
1092 // reexports. We ignore the items here and only use the reexports.
1095 let def_id = self.local_def_id(child_index);
1096 let res = Res::Def(kind, def_id);
1097 let vis = self.get_visibility(child_index);
1098 let span = self.get_span(child_index, sess);
1100 callback(ModChild { ident, res, vis, span });
1102 // For non-re-export structs and variants add their constructors to children.
1103 // Re-export lists automatically contain constructors when necessary.
1105 DefKind::Struct => {
1106 if let Some((ctor_def_id, ctor_kind)) =
1107 self.get_ctor_def_id_and_kind(child_index)
1110 Res::Def(DefKind::Ctor(CtorOf::Struct, ctor_kind), ctor_def_id);
1111 let vis = self.get_visibility(ctor_def_id.index);
1112 callback(ModChild { ident, res: ctor_res, vis, span });
1115 DefKind::Variant => {
1116 // Braced variants, unlike structs, generate unusable names in
1117 // value namespace, they are reserved for possible future use.
1118 // It's ok to use the variant's id as a ctor id since an
1119 // error will be reported on any use of such resolution anyway.
1120 let (ctor_def_id, ctor_kind) = self
1121 .get_ctor_def_id_and_kind(child_index)
1122 .unwrap_or((def_id, CtorKind::Fictive));
1124 Res::Def(DefKind::Ctor(CtorOf::Variant, ctor_kind), ctor_def_id);
1125 let mut vis = self.get_visibility(ctor_def_id.index);
1126 if ctor_def_id == def_id && vis.is_public() {
1127 // For non-exhaustive variants lower the constructor visibility to
1128 // within the crate. We only need this for fictive constructors,
1129 // for other constructors correct visibilities
1130 // were already encoded in metadata.
1131 let mut attrs = self.get_item_attrs(def_id.index, sess);
1132 if attrs.any(|item| item.has_name(sym::non_exhaustive)) {
1133 let crate_def_id = self.local_def_id(CRATE_DEF_INDEX);
1134 vis = ty::Visibility::Restricted(crate_def_id);
1137 callback(ModChild { ident, res: ctor_res, vis, span });
1145 match self.kind(id) {
1146 EntryKind::Mod(exports) => {
1147 for exp in exports.decode((self, sess)) {
1151 EntryKind::Enum(..) | EntryKind::Trait(..) => {}
1152 _ => bug!("`for_each_module_child` is called on a non-module: {:?}", self.def_kind(id)),
1156 fn is_ctfe_mir_available(self, id: DefIndex) -> bool {
1157 self.root.tables.mir_for_ctfe.get(self, id).is_some()
1160 fn is_item_mir_available(self, id: DefIndex) -> bool {
1161 self.root.tables.optimized_mir.get(self, id).is_some()
1164 fn module_expansion(self, id: DefIndex, sess: &Session) -> ExpnId {
1165 match self.kind(id) {
1166 EntryKind::Mod(_) | EntryKind::Enum(_) | EntryKind::Trait(_) => {
1167 self.get_expn_that_defined(id, sess)
1169 _ => panic!("Expected module, found {:?}", self.local_def_id(id)),
1173 fn get_fn_has_self_parameter(self, id: DefIndex) -> bool {
1174 match self.kind(id) {
1175 EntryKind::AssocFn(data) => data.decode(self).has_self,
1180 fn get_associated_item_def_ids(self, tcx: TyCtxt<'tcx>, id: DefIndex) -> &'tcx [DefId] {
1181 if let Some(children) = self.root.tables.children.get(self, id) {
1182 tcx.arena.alloc_from_iter(
1183 children.decode((self, tcx.sess)).map(|child_index| self.local_def_id(child_index)),
1190 fn get_associated_item(self, id: DefIndex) -> ty::AssocItem {
1191 let def_key = self.def_key(id);
1192 let parent = self.local_def_id(def_key.parent.unwrap());
1193 let name = self.item_name(id);
1195 let (kind, container, has_self) = match self.kind(id) {
1196 EntryKind::AssocConst(container) => (ty::AssocKind::Const, container, false),
1197 EntryKind::AssocFn(data) => {
1198 let data = data.decode(self);
1199 (ty::AssocKind::Fn, data.container, data.has_self)
1201 EntryKind::AssocType(container) => (ty::AssocKind::Type, container, false),
1202 _ => bug!("cannot get associated-item of `{:?}`", def_key),
1208 vis: self.get_visibility(id),
1209 defaultness: container.defaultness(),
1210 def_id: self.local_def_id(id),
1211 trait_item_def_id: self.get_trait_item_def_id(id),
1212 container: container.with_def_id(parent),
1213 fn_has_self_parameter: has_self,
1217 fn get_ctor_def_id_and_kind(self, node_id: DefIndex) -> Option<(DefId, CtorKind)> {
1218 match self.kind(node_id) {
1219 EntryKind::Struct(data, _) | EntryKind::Variant(data) => {
1220 let vdata = data.decode(self);
1221 vdata.ctor.map(|index| (self.local_def_id(index), vdata.ctor_kind))
1231 ) -> impl Iterator<Item = ast::Attribute> + 'a {
1236 .unwrap_or_else(|| {
1237 // Structure and variant constructors don't have any attributes encoded for them,
1238 // but we assume that someone passing a constructor ID actually wants to look at
1239 // the attributes on the corresponding struct or variant.
1240 let def_key = self.def_key(id);
1241 assert_eq!(def_key.disambiguated_data.data, DefPathData::Ctor);
1242 let parent_id = def_key.parent.expect("no parent for a constructor");
1246 .get(self, parent_id)
1247 .expect("no encoded attributes for a structure or variant")
1249 .decode((self, sess))
1252 fn get_struct_field_names(
1256 ) -> impl Iterator<Item = Spanned<Symbol>> + 'a {
1261 .unwrap_or_else(Lazy::empty)
1263 .map(move |index| respan(self.get_span(index, sess), self.item_name(index)))
1266 fn get_struct_field_visibilities(self, id: DefIndex) -> impl Iterator<Item = Visibility> + 'a {
1271 .unwrap_or_else(Lazy::empty)
1273 .map(move |field_index| self.get_visibility(field_index))
1276 fn get_inherent_implementations_for_type(
1280 ) -> &'tcx [DefId] {
1281 tcx.arena.alloc_from_iter(
1286 .unwrap_or_else(Lazy::empty)
1288 .map(|index| self.local_def_id(index)),
1292 /// Decodes all inherent impls in the crate (for rustdoc).
1293 fn get_inherent_impls(self) -> impl Iterator<Item = (DefId, DefId)> + 'a {
1294 (0..self.root.tables.inherent_impls.size()).flat_map(move |i| {
1295 let ty_index = DefIndex::from_usize(i);
1296 let ty_def_id = self.local_def_id(ty_index);
1300 .get(self, ty_index)
1301 .unwrap_or_else(Lazy::empty)
1303 .map(move |impl_index| (ty_def_id, self.local_def_id(impl_index)))
1307 /// Decodes all traits in the crate (for rustdoc and rustc diagnostics).
1308 fn get_traits(self) -> impl Iterator<Item = DefId> + 'a {
1309 self.root.traits.decode(self).map(move |index| self.local_def_id(index))
1312 /// Decodes all trait impls in the crate (for rustdoc).
1313 fn get_trait_impls(self) -> impl Iterator<Item = (DefId, DefId, Option<SimplifiedType>)> + 'a {
1314 self.cdata.trait_impls.iter().flat_map(move |((trait_cnum_raw, trait_index), impls)| {
1315 let trait_def_id = DefId {
1316 krate: self.cnum_map[CrateNum::from_u32(*trait_cnum_raw)],
1317 index: *trait_index,
1319 impls.decode(self).map(move |(impl_index, simplified_self_ty)| {
1320 (trait_def_id, self.local_def_id(impl_index), simplified_self_ty)
1325 fn get_implementations_of_trait(
1328 trait_def_id: DefId,
1329 ) -> &'tcx [(DefId, Option<SimplifiedType>)] {
1330 if self.trait_impls.is_empty() {
1334 // Do a reverse lookup beforehand to avoid touching the crate_num
1335 // hash map in the loop below.
1336 let key = match self.reverse_translate_def_id(trait_def_id) {
1337 Some(def_id) => (def_id.krate.as_u32(), def_id.index),
1341 if let Some(impls) = self.trait_impls.get(&key) {
1342 tcx.arena.alloc_from_iter(
1345 .map(|(idx, simplified_self_ty)| (self.local_def_id(idx), simplified_self_ty)),
1352 fn get_trait_of_item(self, id: DefIndex) -> Option<DefId> {
1353 let def_key = self.def_key(id);
1354 match def_key.disambiguated_data.data {
1355 DefPathData::TypeNs(..) | DefPathData::ValueNs(..) => (),
1356 // Not an associated item
1359 def_key.parent.and_then(|parent_index| match self.kind(parent_index) {
1360 EntryKind::Trait(_) | EntryKind::TraitAlias => Some(self.local_def_id(parent_index)),
1365 fn get_native_libraries(self, sess: &'a Session) -> impl Iterator<Item = NativeLib> + 'a {
1366 self.root.native_libraries.decode((self, sess))
1369 fn get_proc_macro_quoted_span(self, index: usize, sess: &Session) -> Span {
1372 .proc_macro_quoted_spans
1374 .unwrap_or_else(|| panic!("Missing proc macro quoted span: {:?}", index))
1375 .decode((self, sess))
1378 fn get_foreign_modules(self, sess: &'a Session) -> impl Iterator<Item = ForeignModule> + '_ {
1379 self.root.foreign_modules.decode((self, sess))
1382 fn get_dylib_dependency_formats(
1385 ) -> &'tcx [(CrateNum, LinkagePreference)] {
1386 tcx.arena.alloc_from_iter(
1387 self.root.dylib_dependency_formats.decode(self).enumerate().flat_map(|(i, link)| {
1388 let cnum = CrateNum::new(i + 1);
1389 link.map(|link| (self.cnum_map[cnum], link))
1394 fn get_missing_lang_items(self, tcx: TyCtxt<'tcx>) -> &'tcx [lang_items::LangItem] {
1395 tcx.arena.alloc_from_iter(self.root.lang_items_missing.decode(self))
1398 fn exported_symbols(
1401 ) -> &'tcx [(ExportedSymbol<'tcx>, SymbolExportLevel)] {
1402 tcx.arena.alloc_from_iter(self.root.exported_symbols.decode((self, tcx)))
1405 fn get_macro(self, id: DefIndex, sess: &Session) -> MacroDef {
1406 match self.kind(id) {
1407 EntryKind::MacroDef(macro_def) => macro_def.decode((self, sess)),
1412 // This replicates some of the logic of the crate-local `is_const_fn_raw` query, because we
1413 // don't serialize constness for tuple variant and tuple struct constructors.
1414 fn is_const_fn_raw(self, id: DefIndex) -> bool {
1415 let constness = match self.kind(id) {
1416 EntryKind::AssocFn(data) => data.decode(self).fn_data.constness,
1417 EntryKind::Fn(data) => data.decode(self).constness,
1418 EntryKind::ForeignFn(data) => data.decode(self).constness,
1419 EntryKind::Variant(..) | EntryKind::Struct(..) => hir::Constness::Const,
1420 _ => hir::Constness::NotConst,
1422 constness == hir::Constness::Const
1425 fn is_foreign_item(self, id: DefIndex) -> bool {
1426 match self.kind(id) {
1427 EntryKind::ForeignImmStatic | EntryKind::ForeignMutStatic | EntryKind::ForeignFn(_) => {
1434 fn static_mutability(self, id: DefIndex) -> Option<hir::Mutability> {
1435 match self.kind(id) {
1436 EntryKind::ImmStatic | EntryKind::ForeignImmStatic => Some(hir::Mutability::Not),
1437 EntryKind::MutStatic | EntryKind::ForeignMutStatic => Some(hir::Mutability::Mut),
1442 fn generator_kind(self, id: DefIndex) -> Option<hir::GeneratorKind> {
1443 match self.kind(id) {
1444 EntryKind::Generator(data) => Some(data),
1450 fn def_key(self, index: DefIndex) -> DefKey {
1455 .or_insert_with(|| self.root.tables.def_keys.get(self, index).unwrap().decode(self))
1458 // Returns the path leading to the thing with this `id`.
1459 fn def_path(self, id: DefIndex) -> DefPath {
1460 debug!("def_path(cnum={:?}, id={:?})", self.cnum, id);
1461 DefPath::make(self.cnum, id, |parent| self.def_key(parent))
1464 fn def_path_hash_unlocked(
1467 def_path_hashes: &mut FxHashMap<DefIndex, DefPathHash>,
1469 *def_path_hashes.entry(index).or_insert_with(|| {
1470 self.root.tables.def_path_hashes.get(self, index).unwrap().decode(self)
1475 fn def_path_hash(self, index: DefIndex) -> DefPathHash {
1476 let mut def_path_hashes = self.def_path_hash_cache.lock();
1477 self.def_path_hash_unlocked(index, &mut def_path_hashes)
1481 fn def_path_hash_to_def_index(self, hash: DefPathHash) -> DefIndex {
1482 self.def_path_hash_map.def_path_hash_to_def_index(&hash)
1485 fn expn_hash_to_expn_id(self, sess: &Session, index_guess: u32, hash: ExpnHash) -> ExpnId {
1486 debug_assert_eq!(ExpnId::from_hash(hash), None);
1487 let index_guess = ExpnIndex::from_u32(index_guess);
1488 let old_hash = self.root.expn_hashes.get(self, index_guess).map(|lazy| lazy.decode(self));
1490 let index = if old_hash == Some(hash) {
1491 // Fast path: the expn and its index is unchanged from the
1492 // previous compilation session. There is no need to decode anything
1496 // Slow path: We need to find out the new `DefIndex` of the provided
1497 // `DefPathHash`, if its still exists. This requires decoding every `DefPathHash`
1498 // stored in this crate.
1499 let map = self.cdata.expn_hash_map.get_or_init(|| {
1500 let end_id = self.root.expn_hashes.size() as u32;
1502 UnhashMap::with_capacity_and_hasher(end_id as usize, Default::default());
1503 for i in 0..end_id {
1504 let i = ExpnIndex::from_u32(i);
1505 if let Some(hash) = self.root.expn_hashes.get(self, i) {
1506 map.insert(hash.decode(self), i);
1514 let data = self.root.expn_data.get(self, index).unwrap().decode((self, sess));
1515 rustc_span::hygiene::register_expn_id(self.cnum, index, data, hash)
1518 /// Imports the source_map from an external crate into the source_map of the crate
1519 /// currently being compiled (the "local crate").
1521 /// The import algorithm works analogous to how AST items are inlined from an
1522 /// external crate's metadata:
1523 /// For every SourceFile in the external source_map an 'inline' copy is created in the
1524 /// local source_map. The correspondence relation between external and local
1525 /// SourceFiles is recorded in the `ImportedSourceFile` objects returned from this
1526 /// function. When an item from an external crate is later inlined into this
1527 /// crate, this correspondence information is used to translate the span
1528 /// information of the inlined item so that it refers the correct positions in
1529 /// the local source_map (see `<decoder::DecodeContext as SpecializedDecoder<Span>>`).
1531 /// The import algorithm in the function below will reuse SourceFiles already
1532 /// existing in the local source_map. For example, even if the SourceFile of some
1533 /// source file of libstd gets imported many times, there will only ever be
1534 /// one SourceFile object for the corresponding file in the local source_map.
1536 /// Note that imported SourceFiles do not actually contain the source code of the
1537 /// file they represent, just information about length, line breaks, and
1538 /// multibyte characters. This information is enough to generate valid debuginfo
1539 /// for items inlined from other crates.
1541 /// Proc macro crates don't currently export spans, so this function does not have
1542 /// to work for them.
1543 fn imported_source_files(self, sess: &Session) -> &'a [ImportedSourceFile] {
1544 // Translate the virtual `/rustc/$hash` prefix back to a real directory
1545 // that should hold actual sources, where possible.
1547 // NOTE: if you update this, you might need to also update bootstrap's code for generating
1548 // the `rust-src` component in `Src::run` in `src/bootstrap/dist.rs`.
1549 let virtual_rust_source_base_dir = option_env!("CFG_VIRTUAL_RUST_SOURCE_BASE_DIR")
1552 // Only spend time on further checks if we have what to translate *to*.
1553 sess.opts.real_rust_source_base_dir.is_some()
1555 .filter(|virtual_dir| {
1556 // Don't translate away `/rustc/$hash` if we're still remapping to it,
1557 // since that means we're still building `std`/`rustc` that need it,
1558 // and we don't want the real path to leak into codegen/debuginfo.
1559 !sess.opts.remap_path_prefix.iter().any(|(_from, to)| to == virtual_dir)
1561 let try_to_translate_virtual_to_real = |name: &mut rustc_span::FileName| {
1563 "try_to_translate_virtual_to_real(name={:?}): \
1564 virtual_rust_source_base_dir={:?}, real_rust_source_base_dir={:?}",
1565 name, virtual_rust_source_base_dir, sess.opts.real_rust_source_base_dir,
1568 if let Some(virtual_dir) = virtual_rust_source_base_dir {
1569 if let Some(real_dir) = &sess.opts.real_rust_source_base_dir {
1570 if let rustc_span::FileName::Real(old_name) = name {
1571 if let rustc_span::RealFileName::Remapped { local_path: _, virtual_name } =
1574 if let Ok(rest) = virtual_name.strip_prefix(virtual_dir) {
1575 let virtual_name = virtual_name.clone();
1577 // The std library crates are in
1578 // `$sysroot/lib/rustlib/src/rust/library`, whereas other crates
1579 // may be in `$sysroot/lib/rustlib/src/rust/` directly. So we
1580 // detect crates from the std libs and handle them specially.
1581 const STD_LIBS: &[&str] = &[
1591 "profiler_builtins",
1593 "rustc-std-workspace-core",
1594 "rustc-std-workspace-alloc",
1595 "rustc-std-workspace-std",
1598 let is_std_lib = STD_LIBS.iter().any(|l| rest.starts_with(l));
1600 let new_path = if is_std_lib {
1601 real_dir.join("library").join(rest)
1607 "try_to_translate_virtual_to_real: `{}` -> `{}`",
1608 virtual_name.display(),
1611 let new_name = rustc_span::RealFileName::Remapped {
1612 local_path: Some(new_path),
1615 *old_name = new_name;
1623 self.cdata.source_map_import_info.get_or_init(|| {
1624 let external_source_map = self.root.source_map.decode(self);
1627 .map(|source_file_to_import| {
1628 // We can't reuse an existing SourceFile, so allocate a new one
1629 // containing the information we need.
1630 let rustc_span::SourceFile {
1636 mut multibyte_chars,
1637 mut non_narrow_chars,
1641 } = source_file_to_import;
1643 // If this file is under $sysroot/lib/rustlib/src/ but has not been remapped
1644 // during rust bootstrapping by `remap-debuginfo = true`, and the user
1645 // wish to simulate that behaviour by -Z simulate-remapped-rust-src-base,
1646 // then we change `name` to a similar state as if the rust was bootstrapped
1647 // with `remap-debuginfo = true`.
1648 // This is useful for testing so that tests about the effects of
1649 // `try_to_translate_virtual_to_real` don't have to worry about how the
1650 // compiler is bootstrapped.
1651 if let Some(virtual_dir) =
1652 &sess.opts.debugging_opts.simulate_remapped_rust_src_base
1654 if let Some(real_dir) = &sess.opts.real_rust_source_base_dir {
1655 if let rustc_span::FileName::Real(ref mut old_name) = name {
1656 if let rustc_span::RealFileName::LocalPath(local) = old_name {
1657 if let Ok(rest) = local.strip_prefix(real_dir) {
1658 *old_name = rustc_span::RealFileName::Remapped {
1660 virtual_name: virtual_dir.join(rest),
1668 // If this file's path has been remapped to `/rustc/$hash`,
1669 // we might be able to reverse that (also see comments above,
1670 // on `try_to_translate_virtual_to_real`).
1671 try_to_translate_virtual_to_real(&mut name);
1673 let source_length = (end_pos - start_pos).to_usize();
1675 // Translate line-start positions and multibyte character
1676 // position into frame of reference local to file.
1677 // `SourceMap::new_imported_source_file()` will then translate those
1678 // coordinates to their new global frame of reference when the
1679 // offset of the SourceFile is known.
1680 for pos in &mut lines {
1681 *pos = *pos - start_pos;
1683 for mbc in &mut multibyte_chars {
1684 mbc.pos = mbc.pos - start_pos;
1686 for swc in &mut non_narrow_chars {
1687 *swc = *swc - start_pos;
1689 for np in &mut normalized_pos {
1690 np.pos = np.pos - start_pos;
1693 let local_version = sess.source_map().new_imported_source_file(
1707 "CrateMetaData::imported_source_files alloc \
1708 source_file {:?} original (start_pos {:?} end_pos {:?}) \
1709 translated (start_pos {:?} end_pos {:?})",
1713 local_version.start_pos,
1714 local_version.end_pos
1717 ImportedSourceFile {
1718 original_start_pos: start_pos,
1719 original_end_pos: end_pos,
1720 translated_source_file: local_version,
1728 impl CrateMetadata {
1732 root: CrateRoot<'static>,
1733 raw_proc_macros: Option<&'static [ProcMacro]>,
1735 cnum_map: CrateNumMap,
1736 dep_kind: CrateDepKind,
1737 source: CrateSource,
1739 host_hash: Option<Svh>,
1740 ) -> CrateMetadata {
1741 let trait_impls = root
1743 .decode((&blob, sess))
1744 .map(|trait_impls| (trait_impls.trait_id, trait_impls.impls))
1746 let alloc_decoding_state =
1747 AllocDecodingState::new(root.interpret_alloc_index.decode(&blob).collect());
1748 let dependencies = Lock::new(cnum_map.iter().cloned().collect());
1750 // Pre-decode the DefPathHash->DefIndex table. This is a cheap operation
1751 // that does not copy any data. It just does some data verification.
1752 let def_path_hash_map = root.def_path_hash_map.decode(&blob);
1759 source_map_import_info: OnceCell::new(),
1761 expn_hash_map: Default::default(),
1762 alloc_decoding_state,
1766 dep_kind: Lock::new(dep_kind),
1767 source: Lrc::new(source),
1770 extern_crate: Lock::new(None),
1771 hygiene_context: Default::default(),
1772 def_key_cache: Default::default(),
1773 def_path_hash_cache: Default::default(),
1777 crate fn dependencies(&self) -> LockGuard<'_, Vec<CrateNum>> {
1778 self.dependencies.borrow()
1781 crate fn add_dependency(&self, cnum: CrateNum) {
1782 self.dependencies.borrow_mut().push(cnum);
1785 crate fn update_extern_crate(&self, new_extern_crate: ExternCrate) -> bool {
1786 let mut extern_crate = self.extern_crate.borrow_mut();
1787 let update = Some(new_extern_crate.rank()) > extern_crate.as_ref().map(ExternCrate::rank);
1789 *extern_crate = Some(new_extern_crate);
1794 crate fn source(&self) -> &CrateSource {
1798 crate fn dep_kind(&self) -> CrateDepKind {
1799 *self.dep_kind.lock()
1802 crate fn update_dep_kind(&self, f: impl FnOnce(CrateDepKind) -> CrateDepKind) {
1803 self.dep_kind.with_lock(|dep_kind| *dep_kind = f(*dep_kind))
1806 crate fn panic_strategy(&self) -> PanicStrategy {
1807 self.root.panic_strategy
1810 crate fn needs_panic_runtime(&self) -> bool {
1811 self.root.needs_panic_runtime
1814 crate fn is_panic_runtime(&self) -> bool {
1815 self.root.panic_runtime
1818 crate fn is_profiler_runtime(&self) -> bool {
1819 self.root.profiler_runtime
1822 crate fn needs_allocator(&self) -> bool {
1823 self.root.needs_allocator
1826 crate fn has_global_allocator(&self) -> bool {
1827 self.root.has_global_allocator
1830 crate fn has_default_lib_allocator(&self) -> bool {
1831 self.root.has_default_lib_allocator
1834 crate fn is_proc_macro_crate(&self) -> bool {
1835 self.root.is_proc_macro_crate()
1838 crate fn name(&self) -> Symbol {
1842 crate fn stable_crate_id(&self) -> StableCrateId {
1843 self.root.stable_crate_id
1846 crate fn hash(&self) -> Svh {
1850 fn num_def_ids(&self) -> usize {
1851 self.root.tables.def_keys.size()
1854 fn local_def_id(&self, index: DefIndex) -> DefId {
1855 DefId { krate: self.cnum, index }
1858 // Translate a DefId from the current compilation environment to a DefId
1859 // for an external crate.
1860 fn reverse_translate_def_id(&self, did: DefId) -> Option<DefId> {
1861 for (local, &global) in self.cnum_map.iter_enumerated() {
1862 if global == did.krate {
1863 return Some(DefId { krate: local, index: did.index });
1871 // Cannot be implemented on 'ProcMacro', as libproc_macro
1872 // does not depend on librustc_ast
1873 fn macro_kind(raw: &ProcMacro) -> MacroKind {
1875 ProcMacro::CustomDerive { .. } => MacroKind::Derive,
1876 ProcMacro::Attr { .. } => MacroKind::Attr,
1877 ProcMacro::Bang { .. } => MacroKind::Bang,