src/librustc_metadata/encoder.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use index::Index;
  12 use index_builder::{FromId, IndexBuilder, Untracked};
  13 use isolated_encoder::IsolatedEncoder;
  14 use schema::*;
  15
  16 use rustc::middle::cstore::{LinkMeta, LinkagePreference, NativeLibrary,
  17                             EncodedMetadata, ForeignModule};
  18 use rustc::hir::def::CtorKind;
  19 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefIndex, DefId, LocalDefId, LOCAL_CRATE};
  20 use rustc::hir::map::definitions::DefPathTable;
  21 use rustc::ich::Fingerprint;
  22 use rustc::middle::dependency_format::Linkage;
  23 use rustc::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel,
  24                                       metadata_symbol_name};
  25 use rustc::middle::lang_items;
  26 use rustc::mir::{self, interpret};
  27 use rustc::traits::specialization_graph;
  28 use rustc::ty::{self, Ty, TyCtxt, ReprOptions, SymbolName};
  29 use rustc::ty::codec::{self as ty_codec, TyEncoder};
  30
  31 use rustc::session::config::{self, CrateType};
  32 use rustc::util::nodemap::FxHashMap;
  33
  34 use rustc_data_structures::stable_hasher::StableHasher;
  35 use rustc_serialize::{Encodable, Encoder, SpecializedEncoder, opaque};
  36
  37 use std::hash::Hash;
  38 use std::path::Path;
  39 use rustc_data_structures::sync::Lrc;
  40 use std::u32;
  41 use syntax::ast::{self, CRATE_NODE_ID};
  42 use syntax::attr;
  43 use syntax::codemap::Spanned;
  44 use syntax::symbol::keywords;
  45 use syntax_pos::{self, hygiene, FileName, FileMap, Span};
  46
  47 use rustc::hir::{self, PatKind};
  48 use rustc::hir::itemlikevisit::ItemLikeVisitor;
  49 use rustc::hir::intravisit::{Visitor, NestedVisitorMap};
  50 use rustc::hir::intravisit;
  51
  52 pub struct EncodeContext<'a, 'tcx: 'a> {
  53     opaque: opaque::Encoder,
  54     pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
  55     link_meta: &'a LinkMeta,
  56
  57     lazy_state: LazyState,
  58     type_shorthands: FxHashMap<Ty<'tcx>, usize>,
  59     predicate_shorthands: FxHashMap<ty::Predicate<'tcx>, usize>,
  60
  61     interpret_allocs: FxHashMap<interpret::AllocId, usize>,
  62     interpret_allocs_inverse: Vec<interpret::AllocId>,
  63
  64     // This is used to speed up Span encoding.
  65     filemap_cache: Lrc<FileMap>,
  66 }
  67
  68 macro_rules! encoder_methods {
  69     ($($name:ident($ty:ty);)*) => {
  70         $(fn $name(&mut self, value: $ty) -> Result<(), Self::Error> {
  71             self.opaque.$name(value)
  72         })*
  73     }
  74 }
  75
  76 impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
  77     type Error = <opaque::Encoder as Encoder>::Error;
  78
  79     fn emit_nil(&mut self) -> Result<(), Self::Error> {
  80         Ok(())
  81     }
  82
  83     encoder_methods! {
  84         emit_usize(usize);
  85         emit_u128(u128);
  86         emit_u64(u64);
  87         emit_u32(u32);
  88         emit_u16(u16);
  89         emit_u8(u8);
  90
  91         emit_isize(isize);
  92         emit_i128(i128);
  93         emit_i64(i64);
  94         emit_i32(i32);
  95         emit_i16(i16);
  96         emit_i8(i8);
  97
  98         emit_bool(bool);
  99         emit_f64(f64);
 100         emit_f32(f32);
 101         emit_char(char);
 102         emit_str(&str);
 103     }
 104 }
 105
 106 impl<'a, 'tcx, T> SpecializedEncoder<Lazy<T>> for EncodeContext<'a, 'tcx> {
 107     fn specialized_encode(&mut self, lazy: &Lazy<T>) -> Result<(), Self::Error> {
 108         self.emit_lazy_distance(lazy.position, Lazy::<T>::min_size())
 109     }
 110 }
 111
 112 impl<'a, 'tcx, T> SpecializedEncoder<LazySeq<T>> for EncodeContext<'a, 'tcx> {
 113     fn specialized_encode(&mut self, seq: &LazySeq<T>) -> Result<(), Self::Error> {
 114         self.emit_usize(seq.len)?;
 115         if seq.len == 0 {
 116             return Ok(());
 117         }
 118         self.emit_lazy_distance(seq.position, LazySeq::<T>::min_size(seq.len))
 119     }
 120 }
 121
 122 impl<'a, 'tcx> SpecializedEncoder<CrateNum> for EncodeContext<'a, 'tcx> {
 123     #[inline]
 124     fn specialized_encode(&mut self, cnum: &CrateNum) -> Result<(), Self::Error> {
 125         self.emit_u32(cnum.as_u32())
 126     }
 127 }
 128
 129 impl<'a, 'tcx> SpecializedEncoder<DefId> for EncodeContext<'a, 'tcx> {
 130     #[inline]
 131     fn specialized_encode(&mut self, def_id: &DefId) -> Result<(), Self::Error> {
 132         let DefId {
 133             krate,
 134             index,
 135         } = *def_id;
 136
 137         krate.encode(self)?;
 138         index.encode(self)
 139     }
 140 }
 141
 142 impl<'a, 'tcx> SpecializedEncoder<DefIndex> for EncodeContext<'a, 'tcx> {
 143     #[inline]
 144     fn specialized_encode(&mut self, def_index: &DefIndex) -> Result<(), Self::Error> {
 145         self.emit_u32(def_index.as_raw_u32())
 146     }
 147 }
 148
 149 impl<'a, 'tcx> SpecializedEncoder<Span> for EncodeContext<'a, 'tcx> {
 150     fn specialized_encode(&mut self, span: &Span) -> Result<(), Self::Error> {
 151         if span.is_dummy() {
 152             return TAG_INVALID_SPAN.encode(self)
 153         }
 154
 155         let span = span.data();
 156
 157         // The Span infrastructure should make sure that this invariant holds:
 158         debug_assert!(span.lo <= span.hi);
 159
 160         if !self.filemap_cache.contains(span.lo) {
 161             let codemap = self.tcx.sess.codemap();
 162             let filemap_index = codemap.lookup_filemap_idx(span.lo);
 163             self.filemap_cache = codemap.files()[filemap_index].clone();
 164         }
 165
 166         if !self.filemap_cache.contains(span.hi) {
 167             // Unfortunately, macro expansion still sometimes generates Spans
 168             // that malformed in this way.
 169             return TAG_INVALID_SPAN.encode(self)
 170         }
 171
 172         TAG_VALID_SPAN.encode(self)?;
 173         span.lo.encode(self)?;
 174
 175         // Encode length which is usually less than span.hi and profits more
 176         // from the variable-length integer encoding that we use.
 177         let len = span.hi - span.lo;
 178         len.encode(self)
 179
 180         // Don't encode the expansion context.
 181     }
 182 }
 183
 184 impl<'a, 'tcx> SpecializedEncoder<LocalDefId> for EncodeContext<'a, 'tcx> {
 185     #[inline]
 186     fn specialized_encode(&mut self, def_id: &LocalDefId) -> Result<(), Self::Error> {
 187         self.specialized_encode(&def_id.to_def_id())
 188     }
 189 }
 190
 191 impl<'a, 'tcx> SpecializedEncoder<Ty<'tcx>> for EncodeContext<'a, 'tcx> {
 192     fn specialized_encode(&mut self, ty: &Ty<'tcx>) -> Result<(), Self::Error> {
 193         ty_codec::encode_with_shorthand(self, ty, |ecx| &mut ecx.type_shorthands)
 194     }
 195 }
 196
 197 impl<'a, 'tcx> SpecializedEncoder<interpret::AllocId> for EncodeContext<'a, 'tcx> {
 198     fn specialized_encode(&mut self, alloc_id: &interpret::AllocId) -> Result<(), Self::Error> {
 199         use std::collections::hash_map::Entry;
 200         let index = match self.interpret_allocs.entry(*alloc_id) {
 201             Entry::Occupied(e) => *e.get(),
 202             Entry::Vacant(e) => {
 203                 let idx = self.interpret_allocs_inverse.len();
 204                 self.interpret_allocs_inverse.push(*alloc_id);
 205                 e.insert(idx);
 206                 idx
 207             },
 208         };
 209
 210         index.encode(self)
 211     }
 212 }
 213
 214 impl<'a, 'tcx> SpecializedEncoder<ty::GenericPredicates<'tcx>> for EncodeContext<'a, 'tcx> {
 215     fn specialized_encode(&mut self,
 216                           predicates: &ty::GenericPredicates<'tcx>)
 217                           -> Result<(), Self::Error> {
 218         ty_codec::encode_predicates(self, predicates, |ecx| &mut ecx.predicate_shorthands)
 219     }
 220 }
 221
 222 impl<'a, 'tcx> SpecializedEncoder<Fingerprint> for EncodeContext<'a, 'tcx> {
 223     fn specialized_encode(&mut self, f: &Fingerprint) -> Result<(), Self::Error> {
 224         f.encode_opaque(&mut self.opaque)
 225     }
 226 }
 227
 228 impl<'a, 'tcx, T: Encodable> SpecializedEncoder<mir::ClearCrossCrate<T>>
 229 for EncodeContext<'a, 'tcx> {
 230     fn specialized_encode(&mut self,
 231                           _: &mir::ClearCrossCrate<T>)
 232                           -> Result<(), Self::Error> {
 233         Ok(())
 234     }
 235 }
 236
 237 impl<'a, 'tcx> TyEncoder for EncodeContext<'a, 'tcx> {
 238     fn position(&self) -> usize {
 239         self.opaque.position()
 240     }
 241 }
 242
 243 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
 244
 245     fn emit_node<F: FnOnce(&mut Self, usize) -> R, R>(&mut self, f: F) -> R {
 246         assert_eq!(self.lazy_state, LazyState::NoNode);
 247         let pos = self.position();
 248         self.lazy_state = LazyState::NodeStart(pos);
 249         let r = f(self, pos);
 250         self.lazy_state = LazyState::NoNode;
 251         r
 252     }
 253
 254     fn emit_lazy_distance(&mut self,
 255                           position: usize,
 256                           min_size: usize)
 257                           -> Result<(), <Self as Encoder>::Error> {
 258         let min_end = position + min_size;
 259         let distance = match self.lazy_state {
 260             LazyState::NoNode => bug!("emit_lazy_distance: outside of a metadata node"),
 261             LazyState::NodeStart(start) => {
 262                 assert!(min_end <= start);
 263                 start - min_end
 264             }
 265             LazyState::Previous(last_min_end) => {
 266                 assert!(
 267                     last_min_end <= position,
 268                     "make sure that the calls to `lazy*` \
 269                     are in the same order as the metadata fields",
 270                 );
 271                 position - last_min_end
 272             }
 273         };
 274         self.lazy_state = LazyState::Previous(min_end);
 275         self.emit_usize(distance)
 276     }
 277
 278     pub fn lazy<T: Encodable>(&mut self, value: &T) -> Lazy<T> {
 279         self.emit_node(|ecx, pos| {
 280             value.encode(ecx).unwrap();
 281
 282             assert!(pos + Lazy::<T>::min_size() <= ecx.position());
 283             Lazy::with_position(pos)
 284         })
 285     }
 286
 287     pub fn lazy_seq<I, T>(&mut self, iter: I) -> LazySeq<T>
 288         where I: IntoIterator<Item = T>,
 289               T: Encodable
 290     {
 291         self.emit_node(|ecx, pos| {
 292             let len = iter.into_iter().map(|value| value.encode(ecx).unwrap()).count();
 293
 294             assert!(pos + LazySeq::<T>::min_size(len) <= ecx.position());
 295             LazySeq::with_position_and_length(pos, len)
 296         })
 297     }
 298
 299     pub fn lazy_seq_ref<'b, I, T>(&mut self, iter: I) -> LazySeq<T>
 300         where I: IntoIterator<Item = &'b T>,
 301               T: 'b + Encodable
 302     {
 303         self.emit_node(|ecx, pos| {
 304             let len = iter.into_iter().map(|value| value.encode(ecx).unwrap()).count();
 305
 306             assert!(pos + LazySeq::<T>::min_size(len) <= ecx.position());
 307             LazySeq::with_position_and_length(pos, len)
 308         })
 309     }
 310
 311     // Encodes something that corresponds to a single DepNode::GlobalMetaData
 312     // and registers the Fingerprint in the `metadata_hashes` map.
 313     pub fn tracked<'x, DATA, R>(&'x mut self,
 314                                 op: fn(&mut IsolatedEncoder<'x, 'a, 'tcx>, DATA) -> R,
 315                                 data: DATA)
 316                                 -> R {
 317         op(&mut IsolatedEncoder::new(self), data)
 318     }
 319
 320     fn encode_info_for_items(&mut self) -> Index {
 321         let krate = self.tcx.hir.krate();
 322         let mut index = IndexBuilder::new(self);
 323         let vis = Spanned { span: syntax_pos::DUMMY_SP, node: hir::VisibilityKind::Public };
 324         index.record(DefId::local(CRATE_DEF_INDEX),
 325                      IsolatedEncoder::encode_info_for_mod,
 326                      FromId(CRATE_NODE_ID, (&krate.module, &krate.attrs, &vis)));
 327         let mut visitor = EncodeVisitor { index: index };
 328         krate.visit_all_item_likes(&mut visitor.as_deep_visitor());
 329         for macro_def in &krate.exported_macros {
 330             visitor.visit_macro_def(macro_def);
 331         }
 332         visitor.index.into_items()
 333     }
 334
 335     fn encode_def_path_table(&mut self) -> Lazy<DefPathTable> {
 336         let definitions = self.tcx.hir.definitions();
 337         self.lazy(definitions.def_path_table())
 338     }
 339
 340     fn encode_codemap(&mut self) -> LazySeq<syntax_pos::FileMap> {
 341         let codemap = self.tcx.sess.codemap();
 342         let all_filemaps = codemap.files();
 343
 344         let (working_dir, working_dir_was_remapped) = self.tcx.sess.working_dir.clone();
 345
 346         let adapted = all_filemaps.iter()
 347             .filter(|filemap| {
 348                 // No need to re-export imported filemaps, as any downstream
 349                 // crate will import them from their original source.
 350                 !filemap.is_imported()
 351             })
 352             .map(|filemap| {
 353                 // When exporting FileMaps, we expand all paths to absolute
 354                 // paths because any relative paths are potentially relative to
 355                 // a wrong directory.
 356                 // However, if a path has been modified via
 357                 // `--remap-path-prefix` we assume the user has already set
 358                 // things up the way they want and don't touch the path values
 359                 // anymore.
 360                 match filemap.name {
 361                     FileName::Real(ref name) => {
 362                         if filemap.name_was_remapped ||
 363                         (name.is_relative() && working_dir_was_remapped) {
 364                             // This path of this FileMap has been modified by
 365                             // path-remapping, so we use it verbatim (and avoid cloning
 366                             // the whole map in the process).
 367                             filemap.clone()
 368                         } else {
 369                             let mut adapted = (**filemap).clone();
 370                             adapted.name = Path::new(&working_dir).join(name).into();
 371                             adapted.name_hash = {
 372                                 let mut hasher: StableHasher<u128> = StableHasher::new();
 373                                 adapted.name.hash(&mut hasher);
 374                                 hasher.finish()
 375                             };
 376                             Lrc::new(adapted)
 377                         }
 378                     },
 379                     // expanded code, not from a file
 380                     _ => filemap.clone(),
 381                 }
 382             })
 383             .collect::<Vec<_>>();
 384
 385         self.lazy_seq_ref(adapted.iter().map(|rc| &**rc))
 386     }
 387
 388     fn encode_crate_root(&mut self) -> Lazy<CrateRoot> {
 389         let mut i = self.position();
 390
 391         let crate_deps = self.tracked(IsolatedEncoder::encode_crate_deps, ());
 392         let dylib_dependency_formats = self.tracked(
 393             IsolatedEncoder::encode_dylib_dependency_formats,
 394             ());
 395         let dep_bytes = self.position() - i;
 396
 397         // Encode the lib features.
 398         i = self.position();
 399         let lib_features = self.tracked(IsolatedEncoder::encode_lib_features, ());
 400         let lib_feature_bytes = self.position() - i;
 401
 402         // Encode the language items.
 403         i = self.position();
 404         let lang_items = self.tracked(IsolatedEncoder::encode_lang_items, ());
 405         let lang_items_missing = self.tracked(
 406             IsolatedEncoder::encode_lang_items_missing,
 407             ());
 408         let lang_item_bytes = self.position() - i;
 409
 410         // Encode the native libraries used
 411         i = self.position();
 412         let native_libraries = self.tracked(
 413             IsolatedEncoder::encode_native_libraries,
 414             ());
 415         let native_lib_bytes = self.position() - i;
 416
 417         let foreign_modules = self.tracked(
 418             IsolatedEncoder::encode_foreign_modules,
 419             ());
 420
 421         // Encode codemap
 422         i = self.position();
 423         let codemap = self.encode_codemap();
 424         let codemap_bytes = self.position() - i;
 425
 426         // Encode DefPathTable
 427         i = self.position();
 428         let def_path_table = self.encode_def_path_table();
 429         let def_path_table_bytes = self.position() - i;
 430
 431         // Encode the def IDs of impls, for coherence checking.
 432         i = self.position();
 433         let impls = self.tracked(IsolatedEncoder::encode_impls, ());
 434         let impl_bytes = self.position() - i;
 435
 436         // Encode exported symbols info.
 437         i = self.position();
 438         let exported_symbols = self.tcx.exported_symbols(LOCAL_CRATE);
 439         let exported_symbols = self.tracked(
 440             IsolatedEncoder::encode_exported_symbols,
 441             &exported_symbols);
 442         let exported_symbols_bytes = self.position() - i;
 443
 444         let tcx = self.tcx;
 445
 446         // Encode the items.
 447         i = self.position();
 448         let items = self.encode_info_for_items();
 449         let item_bytes = self.position() - i;
 450
 451         // Encode the allocation index
 452         let interpret_alloc_index = {
 453             let mut interpret_alloc_index = Vec::new();
 454             let mut n = 0;
 455             trace!("beginning to encode alloc ids");
 456             loop {
 457                 let new_n = self.interpret_allocs_inverse.len();
 458                 // if we have found new ids, serialize those, too
 459                 if n == new_n {
 460                     // otherwise, abort
 461                     break;
 462                 }
 463                 trace!("encoding {} further alloc ids", new_n - n);
 464                 for idx in n..new_n {
 465                     let id = self.interpret_allocs_inverse[idx];
 466                     let pos = self.position() as u32;
 467                     interpret_alloc_index.push(pos);
 468                     interpret::specialized_encode_alloc_id(
 469                         self,
 470                         tcx,
 471                         id,
 472                     ).unwrap();
 473                 }
 474                 n = new_n;
 475             }
 476             self.lazy_seq(interpret_alloc_index)
 477         };
 478
 479         // Index the items
 480         i = self.position();
 481         let index = items.write_index(&mut self.opaque);
 482         let index_bytes = self.position() - i;
 483
 484         let attrs = tcx.hir.krate_attrs();
 485         let link_meta = self.link_meta;
 486         let is_proc_macro = tcx.sess.crate_types.borrow().contains(&CrateType::ProcMacro);
 487         let has_default_lib_allocator = attr::contains_name(&attrs, "default_lib_allocator");
 488         let has_global_allocator = *tcx.sess.has_global_allocator.get();
 489
 490         let root = self.lazy(&CrateRoot {
 491             name: tcx.crate_name(LOCAL_CRATE),
 492             extra_filename: tcx.sess.opts.cg.extra_filename.clone(),
 493             triple: tcx.sess.opts.target_triple.clone(),
 494             hash: link_meta.crate_hash,
 495             disambiguator: tcx.sess.local_crate_disambiguator(),
 496             panic_strategy: tcx.sess.panic_strategy(),
 497             edition: hygiene::default_edition(),
 498             has_global_allocator: has_global_allocator,
 499             has_default_lib_allocator: has_default_lib_allocator,
 500             plugin_registrar_fn: tcx.sess
 501                 .plugin_registrar_fn
 502                 .get()
 503                 .map(|id| tcx.hir.local_def_id(id).index),
 504             macro_derive_registrar: if is_proc_macro {
 505                 let id = tcx.sess.derive_registrar_fn.get().unwrap();
 506                 Some(tcx.hir.local_def_id(id).index)
 507             } else {
 508                 None
 509             },
 510
 511             compiler_builtins: attr::contains_name(&attrs, "compiler_builtins"),
 512             needs_allocator: attr::contains_name(&attrs, "needs_allocator"),
 513             needs_panic_runtime: attr::contains_name(&attrs, "needs_panic_runtime"),
 514             no_builtins: attr::contains_name(&attrs, "no_builtins"),
 515             panic_runtime: attr::contains_name(&attrs, "panic_runtime"),
 516             profiler_runtime: attr::contains_name(&attrs, "profiler_runtime"),
 517             sanitizer_runtime: attr::contains_name(&attrs, "sanitizer_runtime"),
 518
 519             crate_deps,
 520             dylib_dependency_formats,
 521             lib_features,
 522             lang_items,
 523             lang_items_missing,
 524             native_libraries,
 525             foreign_modules,
 526             codemap,
 527             def_path_table,
 528             impls,
 529             exported_symbols,
 530             interpret_alloc_index,
 531             index,
 532         });
 533
 534         let total_bytes = self.position();
 535
 536         if self.tcx.sess.meta_stats() {
 537             let mut zero_bytes = 0;
 538             for e in self.opaque.data.iter() {
 539                 if *e == 0 {
 540                     zero_bytes += 1;
 541                 }
 542             }
 543
 544             println!("metadata stats:");
 545             println!("             dep bytes: {}", dep_bytes);
 546             println!("     lib feature bytes: {}", lib_feature_bytes);
 547             println!("       lang item bytes: {}", lang_item_bytes);
 548             println!("          native bytes: {}", native_lib_bytes);
 549             println!("         codemap bytes: {}", codemap_bytes);
 550             println!("            impl bytes: {}", impl_bytes);
 551             println!("    exp. symbols bytes: {}", exported_symbols_bytes);
 552             println!("  def-path table bytes: {}", def_path_table_bytes);
 553             println!("            item bytes: {}", item_bytes);
 554             println!("           index bytes: {}", index_bytes);
 555             println!("            zero bytes: {}", zero_bytes);
 556             println!("           total bytes: {}", total_bytes);
 557         }
 558
 559         root
 560     }
 561 }
 562
 563 // These are methods for encoding various things. They are meant to be used with
 564 // IndexBuilder::record() and EncodeContext::tracked(). They actually
 565 // would not have to be methods of IsolatedEncoder (free standing functions
 566 // taking IsolatedEncoder as first argument would be just fine) but by making
 567 // them methods we don't have to repeat the lengthy `<'a, 'b: 'a, 'tcx: 'b>`
 568 // clause again and again.
 569 impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
 570     fn encode_variances_of(&mut self, def_id: DefId) -> LazySeq<ty::Variance> {
 571         debug!("IsolatedEncoder::encode_variances_of({:?})", def_id);
 572         let tcx = self.tcx;
 573         self.lazy_seq_from_slice(&tcx.variances_of(def_id))
 574     }
 575
 576     fn encode_item_type(&mut self, def_id: DefId) -> Lazy<Ty<'tcx>> {
 577         let tcx = self.tcx;
 578         let ty = tcx.type_of(def_id);
 579         debug!("IsolatedEncoder::encode_item_type({:?}) => {:?}", def_id, ty);
 580         self.lazy(&ty)
 581     }
 582
 583     /// Encode data for the given variant of the given ADT. The
 584     /// index of the variant is untracked: this is ok because we
 585     /// will have to lookup the adt-def by its id, and that gives us
 586     /// the right to access any information in the adt-def (including,
 587     /// e.g., the length of the various vectors).
 588     fn encode_enum_variant_info(&mut self,
 589                                 (enum_did, Untracked(index)): (DefId, Untracked<usize>))
 590                                 -> Entry<'tcx> {
 591         let tcx = self.tcx;
 592         let def = tcx.adt_def(enum_did);
 593         let variant = &def.variants[index];
 594         let def_id = variant.did;
 595         debug!("IsolatedEncoder::encode_enum_variant_info({:?})", def_id);
 596
 597         let data = VariantData {
 598             ctor_kind: variant.ctor_kind,
 599             discr: variant.discr,
 600             struct_ctor: None,
 601             ctor_sig: if variant.ctor_kind == CtorKind::Fn {
 602                 Some(self.lazy(&tcx.fn_sig(def_id)))
 603             } else {
 604                 None
 605             }
 606         };
 607
 608         let enum_id = tcx.hir.as_local_node_id(enum_did).unwrap();
 609         let enum_vis = &tcx.hir.expect_item(enum_id).vis;
 610
 611         Entry {
 612             kind: EntryKind::Variant(self.lazy(&data)),
 613             visibility: self.lazy(&ty::Visibility::from_hir(enum_vis, enum_id, tcx)),
 614             span: self.lazy(&tcx.def_span(def_id)),
 615             attributes: self.encode_attributes(&tcx.get_attrs(def_id)),
 616             children: self.lazy_seq(variant.fields.iter().map(|f| {
 617                 assert!(f.did.is_local());
 618                 f.did.index
 619             })),
 620             stability: self.encode_stability(def_id),
 621             deprecation: self.encode_deprecation(def_id),
 622
 623             ty: Some(self.encode_item_type(def_id)),
 624             inherent_impls: LazySeq::empty(),
 625             variances: if variant.ctor_kind == CtorKind::Fn {
 626                 self.encode_variances_of(def_id)
 627             } else {
 628                 LazySeq::empty()
 629             },
 630             generics: Some(self.encode_generics(def_id)),
 631             predicates: Some(self.encode_predicates(def_id)),
 632             predicates_defined_on: None,
 633
 634             mir: self.encode_optimized_mir(def_id),
 635         }
 636     }
 637
 638     fn encode_info_for_mod(&mut self,
 639                            FromId(id, (md, attrs, vis)): FromId<(&hir::Mod,
 640                                                                  &[ast::Attribute],
 641                                                                  &hir::Visibility)>)
 642                            -> Entry<'tcx> {
 643         let tcx = self.tcx;
 644         let def_id = tcx.hir.local_def_id(id);
 645         debug!("IsolatedEncoder::encode_info_for_mod({:?})", def_id);
 646
 647         let data = ModData {
 648             reexports: match tcx.module_exports(def_id) {
 649                 Some(ref exports) => self.lazy_seq_from_slice(exports.as_slice()),
 650                 _ => LazySeq::empty(),
 651             },
 652         };
 653
 654         Entry {
 655             kind: EntryKind::Mod(self.lazy(&data)),
 656             visibility: self.lazy(&ty::Visibility::from_hir(vis, id, tcx)),
 657             span: self.lazy(&tcx.def_span(def_id)),
 658             attributes: self.encode_attributes(attrs),
 659             children: self.lazy_seq(md.item_ids.iter().map(|item_id| {
 660                 tcx.hir.local_def_id(item_id.id).index
 661             })),
 662             stability: self.encode_stability(def_id),
 663             deprecation: self.encode_deprecation(def_id),
 664
 665             ty: None,
 666             inherent_impls: LazySeq::empty(),
 667             variances: LazySeq::empty(),
 668             generics: None,
 669             predicates: None,
 670             predicates_defined_on: None,
 671
 672             mir: None
 673         }
 674     }
 675
 676     /// Encode data for the given field of the given variant of the
 677     /// given ADT. The indices of the variant/field are untracked:
 678     /// this is ok because we will have to lookup the adt-def by its
 679     /// id, and that gives us the right to access any information in
 680     /// the adt-def (including, e.g., the length of the various
 681     /// vectors).
 682     fn encode_field(&mut self,
 683                     (adt_def_id, Untracked((variant_index, field_index))): (DefId,
 684                                                                             Untracked<(usize,
 685                                                                                        usize)>))
 686                     -> Entry<'tcx> {
 687         let tcx = self.tcx;
 688         let variant = &tcx.adt_def(adt_def_id).variants[variant_index];
 689         let field = &variant.fields[field_index];
 690
 691         let def_id = field.did;
 692         debug!("IsolatedEncoder::encode_field({:?})", def_id);
 693
 694         let variant_id = tcx.hir.as_local_node_id(variant.did).unwrap();
 695         let variant_data = tcx.hir.expect_variant_data(variant_id);
 696
 697         Entry {
 698             kind: EntryKind::Field,
 699             visibility: self.lazy(&field.vis),
 700             span: self.lazy(&tcx.def_span(def_id)),
 701             attributes: self.encode_attributes(&variant_data.fields()[field_index].attrs),
 702             children: LazySeq::empty(),
 703             stability: self.encode_stability(def_id),
 704             deprecation: self.encode_deprecation(def_id),
 705
 706             ty: Some(self.encode_item_type(def_id)),
 707             inherent_impls: LazySeq::empty(),
 708             variances: LazySeq::empty(),
 709             generics: Some(self.encode_generics(def_id)),
 710             predicates: Some(self.encode_predicates(def_id)),
 711             predicates_defined_on: None,
 712
 713             mir: None,
 714         }
 715     }
 716
 717     fn encode_struct_ctor(&mut self, (adt_def_id, def_id): (DefId, DefId)) -> Entry<'tcx> {
 718         debug!("IsolatedEncoder::encode_struct_ctor({:?})", def_id);
 719         let tcx = self.tcx;
 720         let adt_def = tcx.adt_def(adt_def_id);
 721         let variant = adt_def.non_enum_variant();
 722
 723         let data = VariantData {
 724             ctor_kind: variant.ctor_kind,
 725             discr: variant.discr,
 726             struct_ctor: Some(def_id.index),
 727             ctor_sig: if variant.ctor_kind == CtorKind::Fn {
 728                 Some(self.lazy(&tcx.fn_sig(def_id)))
 729             } else {
 730                 None
 731             }
 732         };
 733
 734         let struct_id = tcx.hir.as_local_node_id(adt_def_id).unwrap();
 735         let struct_vis = &tcx.hir.expect_item(struct_id).vis;
 736         let mut ctor_vis = ty::Visibility::from_hir(struct_vis, struct_id, tcx);
 737         for field in &variant.fields {
 738             if ctor_vis.is_at_least(field.vis, tcx) {
 739                 ctor_vis = field.vis;
 740             }
 741         }
 742
 743         // If the structure is marked as non_exhaustive then lower the visibility
 744         // to within the crate.
 745         if adt_def.is_non_exhaustive() && ctor_vis == ty::Visibility::Public {
 746             ctor_vis = ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX));
 747         }
 748
 749         let repr_options = get_repr_options(&tcx, adt_def_id);
 750
 751         Entry {
 752             kind: EntryKind::Struct(self.lazy(&data), repr_options),
 753             visibility: self.lazy(&ctor_vis),
 754             span: self.lazy(&tcx.def_span(def_id)),
 755             attributes: LazySeq::empty(),
 756             children: LazySeq::empty(),
 757             stability: self.encode_stability(def_id),
 758             deprecation: self.encode_deprecation(def_id),
 759
 760             ty: Some(self.encode_item_type(def_id)),
 761             inherent_impls: LazySeq::empty(),
 762             variances: if variant.ctor_kind == CtorKind::Fn {
 763                 self.encode_variances_of(def_id)
 764             } else {
 765                 LazySeq::empty()
 766             },
 767             generics: Some(self.encode_generics(def_id)),
 768             predicates: Some(self.encode_predicates(def_id)),
 769             predicates_defined_on: None,
 770
 771             mir: self.encode_optimized_mir(def_id),
 772         }
 773     }
 774
 775     fn encode_generics(&mut self, def_id: DefId) -> Lazy<ty::Generics> {
 776         debug!("IsolatedEncoder::encode_generics({:?})", def_id);
 777         let tcx = self.tcx;
 778         self.lazy(tcx.generics_of(def_id))
 779     }
 780
 781     fn encode_predicates(&mut self, def_id: DefId) -> Lazy<ty::GenericPredicates<'tcx>> {
 782         debug!("IsolatedEncoder::encode_predicates({:?})", def_id);
 783         let tcx = self.tcx;
 784         self.lazy(&tcx.predicates_of(def_id))
 785     }
 786
 787     fn encode_predicates_defined_on(&mut self, def_id: DefId) -> Lazy<ty::GenericPredicates<'tcx>> {
 788         debug!("IsolatedEncoder::encode_predicates_defined_on({:?})", def_id);
 789         let tcx = self.tcx;
 790         self.lazy(&tcx.predicates_defined_on(def_id))
 791     }
 792
 793     fn encode_info_for_trait_item(&mut self, def_id: DefId) -> Entry<'tcx> {
 794         debug!("IsolatedEncoder::encode_info_for_trait_item({:?})", def_id);
 795         let tcx = self.tcx;
 796
 797         let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
 798         let ast_item = tcx.hir.expect_trait_item(node_id);
 799         let trait_item = tcx.associated_item(def_id);
 800
 801         let container = match trait_item.defaultness {
 802             hir::Defaultness::Default { has_value: true } =>
 803                 AssociatedContainer::TraitWithDefault,
 804             hir::Defaultness::Default { has_value: false } =>
 805                 AssociatedContainer::TraitRequired,
 806             hir::Defaultness::Final =>
 807                 span_bug!(ast_item.span, "traits cannot have final items"),
 808         };
 809
 810         let kind = match trait_item.kind {
 811             ty::AssociatedKind::Const => {
 812                 let const_qualif =
 813                     if let hir::TraitItemKind::Const(_, Some(body)) = ast_item.node {
 814                         self.const_qualif(0, body)
 815                     } else {
 816                         ConstQualif { mir: 0, ast_promotable: false }
 817                     };
 818
 819                 let rendered =
 820                     hir::print::to_string(&self.tcx.hir, |s| s.print_trait_item(ast_item));
 821                 let rendered_const = self.lazy(&RenderedConst(rendered));
 822
 823                 EntryKind::AssociatedConst(container, const_qualif, rendered_const)
 824             }
 825             ty::AssociatedKind::Method => {
 826                 let fn_data = if let hir::TraitItemKind::Method(_, ref m) = ast_item.node {
 827                     let arg_names = match *m {
 828                         hir::TraitMethod::Required(ref names) => {
 829                             self.encode_fn_arg_names(names)
 830                         }
 831                         hir::TraitMethod::Provided(body) => {
 832                             self.encode_fn_arg_names_for_body(body)
 833                         }
 834                     };
 835                     FnData {
 836                         constness: hir::Constness::NotConst,
 837                         arg_names,
 838                         sig: self.lazy(&tcx.fn_sig(def_id)),
 839                     }
 840                 } else {
 841                     bug!()
 842                 };
 843                 EntryKind::Method(self.lazy(&MethodData {
 844                     fn_data,
 845                     container,
 846                     has_self: trait_item.method_has_self_argument,
 847                 }))
 848             }
 849             ty::AssociatedKind::Type => EntryKind::AssociatedType(container),
 850             ty::AssociatedKind::Existential =>
 851                 span_bug!(ast_item.span, "existential type in trait"),
 852         };
 853
 854         Entry {
 855             kind,
 856             visibility: self.lazy(&trait_item.vis),
 857             span: self.lazy(&ast_item.span),
 858             attributes: self.encode_attributes(&ast_item.attrs),
 859             children: LazySeq::empty(),
 860             stability: self.encode_stability(def_id),
 861             deprecation: self.encode_deprecation(def_id),
 862
 863             ty: match trait_item.kind {
 864                 ty::AssociatedKind::Const |
 865                 ty::AssociatedKind::Method => {
 866                     Some(self.encode_item_type(def_id))
 867                 }
 868                 ty::AssociatedKind::Type => {
 869                     if trait_item.defaultness.has_value() {
 870                         Some(self.encode_item_type(def_id))
 871                     } else {
 872                         None
 873                     }
 874                 }
 875                 ty::AssociatedKind::Existential => unreachable!(),
 876             },
 877             inherent_impls: LazySeq::empty(),
 878             variances: if trait_item.kind == ty::AssociatedKind::Method {
 879                 self.encode_variances_of(def_id)
 880             } else {
 881                 LazySeq::empty()
 882             },
 883             generics: Some(self.encode_generics(def_id)),
 884             predicates: Some(self.encode_predicates(def_id)),
 885             predicates_defined_on: None,
 886
 887             mir: self.encode_optimized_mir(def_id),
 888         }
 889     }
 890
 891     fn metadata_output_only(&self) -> bool {
 892         // MIR optimisation can be skipped when we're just interested in the metadata.
 893         !self.tcx.sess.opts.output_types.should_codegen()
 894     }
 895
 896     fn const_qualif(&self, mir: u8, body_id: hir::BodyId) -> ConstQualif {
 897         let body_owner_def_id = self.tcx.hir.body_owner_def_id(body_id);
 898         let ast_promotable = self.tcx.const_is_rvalue_promotable_to_static(body_owner_def_id);
 899
 900         ConstQualif { mir, ast_promotable }
 901     }
 902
 903     fn encode_info_for_impl_item(&mut self, def_id: DefId) -> Entry<'tcx> {
 904         debug!("IsolatedEncoder::encode_info_for_impl_item({:?})", def_id);
 905         let tcx = self.tcx;
 906
 907         let node_id = self.tcx.hir.as_local_node_id(def_id).unwrap();
 908         let ast_item = self.tcx.hir.expect_impl_item(node_id);
 909         let impl_item = self.tcx.associated_item(def_id);
 910
 911         let container = match impl_item.defaultness {
 912             hir::Defaultness::Default { has_value: true } => AssociatedContainer::ImplDefault,
 913             hir::Defaultness::Final => AssociatedContainer::ImplFinal,
 914             hir::Defaultness::Default { has_value: false } =>
 915                 span_bug!(ast_item.span, "impl items always have values (currently)"),
 916         };
 917
 918         let kind = match impl_item.kind {
 919             ty::AssociatedKind::Const => {
 920                 if let hir::ImplItemKind::Const(_, body_id) = ast_item.node {
 921                     let mir = self.tcx.at(ast_item.span).mir_const_qualif(def_id).0;
 922
 923                     EntryKind::AssociatedConst(container,
 924                         self.const_qualif(mir, body_id),
 925                         self.encode_rendered_const_for_body(body_id))
 926                 } else {
 927                     bug!()
 928                 }
 929             }
 930             ty::AssociatedKind::Method => {
 931                 let fn_data = if let hir::ImplItemKind::Method(ref sig, body) = ast_item.node {
 932                     FnData {
 933                         constness: sig.header.constness,
 934                         arg_names: self.encode_fn_arg_names_for_body(body),
 935                         sig: self.lazy(&tcx.fn_sig(def_id)),
 936                     }
 937                 } else {
 938                     bug!()
 939                 };
 940                 EntryKind::Method(self.lazy(&MethodData {
 941                     fn_data,
 942                     container,
 943                     has_self: impl_item.method_has_self_argument,
 944                 }))
 945             }
 946             ty::AssociatedKind::Existential => EntryKind::AssociatedExistential(container),
 947             ty::AssociatedKind::Type => EntryKind::AssociatedType(container)
 948         };
 949
 950         let mir =
 951             match ast_item.node {
 952                 hir::ImplItemKind::Const(..) => true,
 953                 hir::ImplItemKind::Method(ref sig, _) => {
 954                     let generics = self.tcx.generics_of(def_id);
 955                     let needs_inline = (generics.requires_monomorphization(self.tcx) ||
 956                                         tcx.codegen_fn_attrs(def_id).requests_inline()) &&
 957                                         !self.metadata_output_only();
 958                     let is_const_fn = sig.header.constness == hir::Constness::Const;
 959                     let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
 960                     needs_inline || is_const_fn || always_encode_mir
 961                 },
 962                 hir::ImplItemKind::Existential(..) |
 963                 hir::ImplItemKind::Type(..) => false,
 964             };
 965
 966         Entry {
 967             kind,
 968             visibility: self.lazy(&impl_item.vis),
 969             span: self.lazy(&ast_item.span),
 970             attributes: self.encode_attributes(&ast_item.attrs),
 971             children: LazySeq::empty(),
 972             stability: self.encode_stability(def_id),
 973             deprecation: self.encode_deprecation(def_id),
 974
 975             ty: Some(self.encode_item_type(def_id)),
 976             inherent_impls: LazySeq::empty(),
 977             variances: if impl_item.kind == ty::AssociatedKind::Method {
 978                 self.encode_variances_of(def_id)
 979             } else {
 980                 LazySeq::empty()
 981             },
 982             generics: Some(self.encode_generics(def_id)),
 983             predicates: Some(self.encode_predicates(def_id)),
 984             predicates_defined_on: None,
 985
 986             mir: if mir { self.encode_optimized_mir(def_id) } else { None },
 987         }
 988     }
 989
 990     fn encode_fn_arg_names_for_body(&mut self, body_id: hir::BodyId)
 991                                     -> LazySeq<ast::Name> {
 992         self.tcx.dep_graph.with_ignore(|| {
 993             let body = self.tcx.hir.body(body_id);
 994             self.lazy_seq(body.arguments.iter().map(|arg| {
 995                 match arg.pat.node {
 996                     PatKind::Binding(_, _, ident, _) => ident.name,
 997                     _ => keywords::Invalid.name(),
 998                 }
 999             }))
1000         })
1001     }
1002
1003     fn encode_fn_arg_names(&mut self, param_names: &[ast::Ident]) -> LazySeq<ast::Name> {
1004         self.lazy_seq(param_names.iter().map(|ident| ident.name))
1005     }
1006
1007     fn encode_optimized_mir(&mut self, def_id: DefId) -> Option<Lazy<mir::Mir<'tcx>>> {
1008         debug!("EntryBuilder::encode_mir({:?})", def_id);
1009         if self.tcx.mir_keys(LOCAL_CRATE).contains(&def_id) {
1010             let mir = self.tcx.optimized_mir(def_id);
1011             Some(self.lazy(&mir))
1012         } else {
1013             None
1014         }
1015     }
1016
1017     // Encodes the inherent implementations of a structure, enumeration, or trait.
1018     fn encode_inherent_implementations(&mut self, def_id: DefId) -> LazySeq<DefIndex> {
1019         debug!("IsolatedEncoder::encode_inherent_implementations({:?})", def_id);
1020         let implementations = self.tcx.inherent_impls(def_id);
1021         if implementations.is_empty() {
1022             LazySeq::empty()
1023         } else {
1024             self.lazy_seq(implementations.iter().map(|&def_id| {
1025                 assert!(def_id.is_local());
1026                 def_id.index
1027             }))
1028         }
1029     }
1030
1031     fn encode_stability(&mut self, def_id: DefId) -> Option<Lazy<attr::Stability>> {
1032         debug!("IsolatedEncoder::encode_stability({:?})", def_id);
1033         self.tcx.lookup_stability(def_id).map(|stab| self.lazy(stab))
1034     }
1035
1036     fn encode_deprecation(&mut self, def_id: DefId) -> Option<Lazy<attr::Deprecation>> {
1037         debug!("IsolatedEncoder::encode_deprecation({:?})", def_id);
1038         self.tcx.lookup_deprecation(def_id).map(|depr| self.lazy(&depr))
1039     }
1040
1041     fn encode_rendered_const_for_body(&mut self, body_id: hir::BodyId) -> Lazy<RenderedConst> {
1042         let body = self.tcx.hir.body(body_id);
1043         let rendered = hir::print::to_string(&self.tcx.hir, |s| s.print_expr(&body.value));
1044         let rendered_const = &RenderedConst(rendered);
1045         self.lazy(rendered_const)
1046     }
1047
1048     fn encode_info_for_item(&mut self, (def_id, item): (DefId, &'tcx hir::Item)) -> Entry<'tcx> {
1049         let tcx = self.tcx;
1050
1051         debug!("IsolatedEncoder::encode_info_for_item({:?})", def_id);
1052
1053         let kind = match item.node {
1054             hir::ItemKind::Static(_, hir::MutMutable, _) => EntryKind::MutStatic,
1055             hir::ItemKind::Static(_, hir::MutImmutable, _) => EntryKind::ImmStatic,
1056             hir::ItemKind::Const(_, body_id) => {
1057                 let mir = tcx.at(item.span).mir_const_qualif(def_id).0;
1058                 EntryKind::Const(
1059                     self.const_qualif(mir, body_id),
1060                     self.encode_rendered_const_for_body(body_id)
1061                 )
1062             }
1063             hir::ItemKind::Fn(_, header, .., body) => {
1064                 let data = FnData {
1065                     constness: header.constness,
1066                     arg_names: self.encode_fn_arg_names_for_body(body),
1067                     sig: self.lazy(&tcx.fn_sig(def_id)),
1068                 };
1069
1070                 EntryKind::Fn(self.lazy(&data))
1071             }
1072             hir::ItemKind::Mod(ref m) => {
1073                 return self.encode_info_for_mod(FromId(item.id, (m, &item.attrs, &item.vis)));
1074             }
1075             hir::ItemKind::ForeignMod(_) => EntryKind::ForeignMod,
1076             hir::ItemKind::GlobalAsm(..) => EntryKind::GlobalAsm,
1077             hir::ItemKind::Ty(..) => EntryKind::Type,
1078             hir::ItemKind::Existential(..) => EntryKind::Existential,
1079             hir::ItemKind::Enum(..) => EntryKind::Enum(get_repr_options(&tcx, def_id)),
1080             hir::ItemKind::Struct(ref struct_def, _) => {
1081                 let variant = tcx.adt_def(def_id).non_enum_variant();
1082
1083                 // Encode def_ids for each field and method
1084                 // for methods, write all the stuff get_trait_method
1085                 // needs to know
1086                 let struct_ctor = if !struct_def.is_struct() {
1087                     Some(tcx.hir.local_def_id(struct_def.id()).index)
1088                 } else {
1089                     None
1090                 };
1091
1092                 let repr_options = get_repr_options(&tcx, def_id);
1093
1094                 EntryKind::Struct(self.lazy(&VariantData {
1095                     ctor_kind: variant.ctor_kind,
1096                     discr: variant.discr,
1097                     struct_ctor,
1098                     ctor_sig: None,
1099                 }), repr_options)
1100             }
1101             hir::ItemKind::Union(..) => {
1102                 let variant = tcx.adt_def(def_id).non_enum_variant();
1103                 let repr_options = get_repr_options(&tcx, def_id);
1104
1105                 EntryKind::Union(self.lazy(&VariantData {
1106                     ctor_kind: variant.ctor_kind,
1107                     discr: variant.discr,
1108                     struct_ctor: None,
1109                     ctor_sig: None,
1110                 }), repr_options)
1111             }
1112             hir::ItemKind::Impl(_, polarity, defaultness, ..) => {
1113                 let trait_ref = tcx.impl_trait_ref(def_id);
1114                 let parent = if let Some(trait_ref) = trait_ref {
1115                     let trait_def = tcx.trait_def(trait_ref.def_id);
1116                     trait_def.ancestors(tcx, def_id).skip(1).next().and_then(|node| {
1117                         match node {
1118                             specialization_graph::Node::Impl(parent) => Some(parent),
1119                             _ => None,
1120                         }
1121                     })
1122                 } else {
1123                     None
1124                 };
1125
1126                 // if this is an impl of `CoerceUnsized`, create its
1127                 // "unsized info", else just store None
1128                 let coerce_unsized_info =
1129                     trait_ref.and_then(|t| {
1130                         if Some(t.def_id) == tcx.lang_items().coerce_unsized_trait() {
1131                             Some(tcx.at(item.span).coerce_unsized_info(def_id))
1132                         } else {
1133                             None
1134                         }
1135                     });
1136
1137                 let data = ImplData {
1138                     polarity,
1139                     defaultness,
1140                     parent_impl: parent,
1141                     coerce_unsized_info,
1142                     trait_ref: trait_ref.map(|trait_ref| self.lazy(&trait_ref)),
1143                 };
1144
1145                 EntryKind::Impl(self.lazy(&data))
1146             }
1147             hir::ItemKind::Trait(..) => {
1148                 let trait_def = tcx.trait_def(def_id);
1149                 let data = TraitData {
1150                     unsafety: trait_def.unsafety,
1151                     paren_sugar: trait_def.paren_sugar,
1152                     has_auto_impl: tcx.trait_is_auto(def_id),
1153                     super_predicates: self.lazy(&tcx.super_predicates_of(def_id)),
1154                 };
1155
1156                 EntryKind::Trait(self.lazy(&data))
1157             }
1158             hir::ItemKind::ExternCrate(_) |
1159             hir::ItemKind::TraitAlias(..) |
1160             hir::ItemKind::Use(..) => bug!("cannot encode info for item {:?}", item),
1161         };
1162
1163         Entry {
1164             kind,
1165             visibility: self.lazy(&ty::Visibility::from_hir(&item.vis, item.id, tcx)),
1166             span: self.lazy(&item.span),
1167             attributes: self.encode_attributes(&item.attrs),
1168             children: match item.node {
1169                 hir::ItemKind::ForeignMod(ref fm) => {
1170                     self.lazy_seq(fm.items
1171                         .iter()
1172                         .map(|foreign_item| tcx.hir.local_def_id(foreign_item.id).index))
1173                 }
1174                 hir::ItemKind::Enum(..) => {
1175                     let def = self.tcx.adt_def(def_id);
1176                     self.lazy_seq(def.variants.iter().map(|v| {
1177                         assert!(v.did.is_local());
1178                         v.did.index
1179                     }))
1180                 }
1181                 hir::ItemKind::Struct(..) |
1182                 hir::ItemKind::Union(..) => {
1183                     let def = self.tcx.adt_def(def_id);
1184                     self.lazy_seq(def.non_enum_variant().fields.iter().map(|f| {
1185                         assert!(f.did.is_local());
1186                         f.did.index
1187                     }))
1188                 }
1189                 hir::ItemKind::Impl(..) |
1190                 hir::ItemKind::Trait(..) => {
1191                     self.lazy_seq(tcx.associated_item_def_ids(def_id).iter().map(|&def_id| {
1192                         assert!(def_id.is_local());
1193                         def_id.index
1194                     }))
1195                 }
1196                 _ => LazySeq::empty(),
1197             },
1198             stability: self.encode_stability(def_id),
1199             deprecation: self.encode_deprecation(def_id),
1200
1201             ty: match item.node {
1202                 hir::ItemKind::Static(..) |
1203                 hir::ItemKind::Const(..) |
1204                 hir::ItemKind::Fn(..) |
1205                 hir::ItemKind::Ty(..) |
1206                 hir::ItemKind::Existential(..) |
1207                 hir::ItemKind::Enum(..) |
1208                 hir::ItemKind::Struct(..) |
1209                 hir::ItemKind::Union(..) |
1210                 hir::ItemKind::Impl(..) => Some(self.encode_item_type(def_id)),
1211                 _ => None,
1212             },
1213             inherent_impls: self.encode_inherent_implementations(def_id),
1214             variances: match item.node {
1215                 hir::ItemKind::Enum(..) |
1216                 hir::ItemKind::Struct(..) |
1217                 hir::ItemKind::Union(..) |
1218                 hir::ItemKind::Fn(..) => self.encode_variances_of(def_id),
1219                 _ => LazySeq::empty(),
1220             },
1221             generics: match item.node {
1222                 hir::ItemKind::Static(..) |
1223                 hir::ItemKind::Const(..) |
1224                 hir::ItemKind::Fn(..) |
1225                 hir::ItemKind::Ty(..) |
1226                 hir::ItemKind::Enum(..) |
1227                 hir::ItemKind::Struct(..) |
1228                 hir::ItemKind::Union(..) |
1229                 hir::ItemKind::Impl(..) |
1230                 hir::ItemKind::Existential(..) |
1231                 hir::ItemKind::Trait(..) => Some(self.encode_generics(def_id)),
1232                 _ => None,
1233             },
1234             predicates: match item.node {
1235                 hir::ItemKind::Static(..) |
1236                 hir::ItemKind::Const(..) |
1237                 hir::ItemKind::Fn(..) |
1238                 hir::ItemKind::Ty(..) |
1239                 hir::ItemKind::Enum(..) |
1240                 hir::ItemKind::Struct(..) |
1241                 hir::ItemKind::Union(..) |
1242                 hir::ItemKind::Impl(..) |
1243                 hir::ItemKind::Existential(..) |
1244                 hir::ItemKind::Trait(..) => Some(self.encode_predicates(def_id)),
1245                 _ => None,
1246             },
1247
1248             // The only time that `predicates_defined_on` is used (on
1249             // an external item) is for traits, during chalk lowering,
1250             // so only encode it in that case as an efficiency
1251             // hack. (No reason not to expand it in the future if
1252             // necessary.)
1253             predicates_defined_on: match item.node {
1254                 hir::ItemKind::Trait(..) => Some(self.encode_predicates_defined_on(def_id)),
1255                 _ => None, // not *wrong* for other kinds of items, but not needed
1256             },
1257
1258             mir: match item.node {
1259                 hir::ItemKind::Static(..) => {
1260                     self.encode_optimized_mir(def_id)
1261                 }
1262                 hir::ItemKind::Const(..) => self.encode_optimized_mir(def_id),
1263                 hir::ItemKind::Fn(_, header, ..) => {
1264                     let generics = tcx.generics_of(def_id);
1265                     let has_types = generics.params.iter().any(|param| match param.kind {
1266                         ty::GenericParamDefKind::Type { .. } => true,
1267                         _ => false,
1268                     });
1269                     let needs_inline =
1270                         (has_types || tcx.codegen_fn_attrs(def_id).requests_inline()) &&
1271                             !self.metadata_output_only();
1272                     let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
1273                     if needs_inline
1274                         || header.constness == hir::Constness::Const
1275                         || always_encode_mir
1276                     {
1277                         self.encode_optimized_mir(def_id)
1278                     } else {
1279                         None
1280                     }
1281                 }
1282                 _ => None,
1283             },
1284         }
1285     }
1286
1287     /// Serialize the text of exported macros
1288     fn encode_info_for_macro_def(&mut self, macro_def: &hir::MacroDef) -> Entry<'tcx> {
1289         use syntax::print::pprust;
1290         let def_id = self.tcx.hir.local_def_id(macro_def.id);
1291         Entry {
1292             kind: EntryKind::MacroDef(self.lazy(&MacroDef {
1293                 body: pprust::tts_to_string(&macro_def.body.trees().collect::<Vec<_>>()),
1294                 legacy: macro_def.legacy,
1295             })),
1296             visibility: self.lazy(&ty::Visibility::Public),
1297             span: self.lazy(&macro_def.span),
1298             attributes: self.encode_attributes(&macro_def.attrs),
1299             stability: self.encode_stability(def_id),
1300             deprecation: self.encode_deprecation(def_id),
1301
1302             children: LazySeq::empty(),
1303             ty: None,
1304             inherent_impls: LazySeq::empty(),
1305             variances: LazySeq::empty(),
1306             generics: None,
1307             predicates: None,
1308             predicates_defined_on: None,
1309             mir: None,
1310         }
1311     }
1312
1313     fn encode_info_for_ty_param(&mut self,
1314                                 (def_id, Untracked(has_default)): (DefId, Untracked<bool>))
1315                                 -> Entry<'tcx> {
1316         debug!("IsolatedEncoder::encode_info_for_ty_param({:?})", def_id);
1317         let tcx = self.tcx;
1318         Entry {
1319             kind: EntryKind::Type,
1320             visibility: self.lazy(&ty::Visibility::Public),
1321             span: self.lazy(&tcx.def_span(def_id)),
1322             attributes: LazySeq::empty(),
1323             children: LazySeq::empty(),
1324             stability: None,
1325             deprecation: None,
1326
1327             ty: if has_default {
1328                 Some(self.encode_item_type(def_id))
1329             } else {
1330                 None
1331             },
1332             inherent_impls: LazySeq::empty(),
1333             variances: LazySeq::empty(),
1334             generics: None,
1335             predicates: None,
1336             predicates_defined_on: None,
1337
1338             mir: None,
1339         }
1340     }
1341
1342     fn encode_info_for_closure(&mut self, def_id: DefId) -> Entry<'tcx> {
1343         debug!("IsolatedEncoder::encode_info_for_closure({:?})", def_id);
1344         let tcx = self.tcx;
1345
1346         let tables = self.tcx.typeck_tables_of(def_id);
1347         let node_id = self.tcx.hir.as_local_node_id(def_id).unwrap();
1348         let hir_id = self.tcx.hir.node_to_hir_id(node_id);
1349         let kind = match tables.node_id_to_type(hir_id).sty {
1350             ty::TyGenerator(def_id, ..) => {
1351                 let layout = self.tcx.generator_layout(def_id);
1352                 let data = GeneratorData {
1353                     layout: layout.clone(),
1354                 };
1355                 EntryKind::Generator(self.lazy(&data))
1356             }
1357
1358             ty::TyClosure(def_id, substs) => {
1359                 let sig = substs.closure_sig(def_id, self.tcx);
1360                 let data = ClosureData { sig: self.lazy(&sig) };
1361                 EntryKind::Closure(self.lazy(&data))
1362             }
1363
1364             _ => bug!("closure that is neither generator nor closure")
1365         };
1366
1367         Entry {
1368             kind,
1369             visibility: self.lazy(&ty::Visibility::Public),
1370             span: self.lazy(&tcx.def_span(def_id)),
1371             attributes: self.encode_attributes(&tcx.get_attrs(def_id)),
1372             children: LazySeq::empty(),
1373             stability: None,
1374             deprecation: None,
1375
1376             ty: Some(self.encode_item_type(def_id)),
1377             inherent_impls: LazySeq::empty(),
1378             variances: LazySeq::empty(),
1379             generics: Some(self.encode_generics(def_id)),
1380             predicates: None,
1381             predicates_defined_on: None,
1382
1383             mir: self.encode_optimized_mir(def_id),
1384         }
1385     }
1386
1387     fn encode_info_for_anon_const(&mut self, def_id: DefId) -> Entry<'tcx> {
1388         debug!("IsolatedEncoder::encode_info_for_anon_const({:?})", def_id);
1389         let tcx = self.tcx;
1390         let id = tcx.hir.as_local_node_id(def_id).unwrap();
1391         let body_id = tcx.hir.body_owned_by(id);
1392         let const_data = self.encode_rendered_const_for_body(body_id);
1393         let mir = tcx.mir_const_qualif(def_id).0;
1394
1395         Entry {
1396             kind: EntryKind::Const(self.const_qualif(mir, body_id), const_data),
1397             visibility: self.lazy(&ty::Visibility::Public),
1398             span: self.lazy(&tcx.def_span(def_id)),
1399             attributes: LazySeq::empty(),
1400             children: LazySeq::empty(),
1401             stability: None,
1402             deprecation: None,
1403
1404             ty: Some(self.encode_item_type(def_id)),
1405             inherent_impls: LazySeq::empty(),
1406             variances: LazySeq::empty(),
1407             generics: Some(self.encode_generics(def_id)),
1408             predicates: Some(self.encode_predicates(def_id)),
1409             predicates_defined_on: None,
1410
1411             mir: self.encode_optimized_mir(def_id),
1412         }
1413     }
1414
1415     fn encode_attributes(&mut self, attrs: &[ast::Attribute]) -> LazySeq<ast::Attribute> {
1416         // NOTE: This must use lazy_seq_from_slice(), not lazy_seq() because
1417         //       we rely on the HashStable specialization for [Attribute]
1418         //       to properly filter things out.
1419         self.lazy_seq_from_slice(attrs)
1420     }
1421
1422     fn encode_native_libraries(&mut self, _: ()) -> LazySeq<NativeLibrary> {
1423         let used_libraries = self.tcx.native_libraries(LOCAL_CRATE);
1424         self.lazy_seq(used_libraries.iter().cloned())
1425     }
1426
1427     fn encode_foreign_modules(&mut self, _: ()) -> LazySeq<ForeignModule> {
1428         let foreign_modules = self.tcx.foreign_modules(LOCAL_CRATE);
1429         self.lazy_seq(foreign_modules.iter().cloned())
1430     }
1431
1432     fn encode_crate_deps(&mut self, _: ()) -> LazySeq<CrateDep> {
1433         let crates = self.tcx.crates();
1434
1435         let mut deps = crates
1436             .iter()
1437             .map(|&cnum| {
1438                 let dep = CrateDep {
1439                     name: self.tcx.original_crate_name(cnum),
1440                     hash: self.tcx.crate_hash(cnum),
1441                     kind: self.tcx.dep_kind(cnum),
1442                     extra_filename: self.tcx.extra_filename(cnum),
1443                 };
1444                 (cnum, dep)
1445             })
1446             .collect::<Vec<_>>();
1447
1448         deps.sort_by_key(|&(cnum, _)| cnum);
1449
1450         {
1451             // Sanity-check the crate numbers
1452             let mut expected_cnum = 1;
1453             for &(n, _) in &deps {
1454                 assert_eq!(n, CrateNum::new(expected_cnum));
1455                 expected_cnum += 1;
1456             }
1457         }
1458
1459         // We're just going to write a list of crate 'name-hash-version's, with
1460         // the assumption that they are numbered 1 to n.
1461         // FIXME (#2166): This is not nearly enough to support correct versioning
1462         // but is enough to get transitive crate dependencies working.
1463         self.lazy_seq_ref(deps.iter().map(|&(_, ref dep)| dep))
1464     }
1465
1466     fn encode_lib_features(&mut self, _: ()) -> LazySeq<(ast::Name, Option<ast::Name>)> {
1467         let tcx = self.tcx;
1468         let lib_features = tcx.lib_features();
1469         self.lazy_seq(lib_features.to_vec())
1470     }
1471
1472     fn encode_lang_items(&mut self, _: ()) -> LazySeq<(DefIndex, usize)> {
1473         let tcx = self.tcx;
1474         let lang_items = tcx.lang_items();
1475         let lang_items = lang_items.items().iter();
1476         self.lazy_seq(lang_items.enumerate().filter_map(|(i, &opt_def_id)| {
1477             if let Some(def_id) = opt_def_id {
1478                 if def_id.is_local() {
1479                     return Some((def_id.index, i));
1480                 }
1481             }
1482             None
1483         }))
1484     }
1485
1486     fn encode_lang_items_missing(&mut self, _: ()) -> LazySeq<lang_items::LangItem> {
1487         let tcx = self.tcx;
1488         self.lazy_seq_ref(&tcx.lang_items().missing)
1489     }
1490
1491     /// Encodes an index, mapping each trait to its (local) implementations.
1492     fn encode_impls(&mut self, _: ()) -> LazySeq<TraitImpls> {
1493         debug!("IsolatedEncoder::encode_impls()");
1494         let tcx = self.tcx;
1495         let mut visitor = ImplVisitor {
1496             tcx,
1497             impls: FxHashMap(),
1498         };
1499         tcx.hir.krate().visit_all_item_likes(&mut visitor);
1500
1501         let mut all_impls: Vec<_> = visitor.impls.into_iter().collect();
1502
1503         // Bring everything into deterministic order for hashing
1504         all_impls.sort_by_cached_key(|&(trait_def_id, _)| {
1505             tcx.def_path_hash(trait_def_id)
1506         });
1507
1508         let all_impls: Vec<_> = all_impls
1509             .into_iter()
1510             .map(|(trait_def_id, mut impls)| {
1511                 // Bring everything into deterministic order for hashing
1512                 impls.sort_by_cached_key(|&def_index| {
1513                     tcx.hir.definitions().def_path_hash(def_index)
1514                 });
1515
1516                 TraitImpls {
1517                     trait_id: (trait_def_id.krate.as_u32(), trait_def_id.index),
1518                     impls: self.lazy_seq_from_slice(&impls[..]),
1519                 }
1520             })
1521             .collect();
1522
1523         self.lazy_seq_from_slice(&all_impls[..])
1524     }
1525
1526     // Encodes all symbols exported from this crate into the metadata.
1527     //
1528     // This pass is seeded off the reachability list calculated in the
1529     // middle::reachable module but filters out items that either don't have a
1530     // symbol associated with them (they weren't translated) or if they're an FFI
1531     // definition (as that's not defined in this crate).
1532     fn encode_exported_symbols(&mut self,
1533                                exported_symbols: &[(ExportedSymbol, SymbolExportLevel)])
1534                                -> EncodedExportedSymbols {
1535         // The metadata symbol name is special. It should not show up in
1536         // downstream crates.
1537         let metadata_symbol_name = SymbolName::new(&metadata_symbol_name(self.tcx));
1538
1539         let lazy_seq = self.lazy_seq(exported_symbols
1540             .iter()
1541             .filter(|&&(ref exported_symbol, _)| {
1542                 match *exported_symbol {
1543                     ExportedSymbol::NoDefId(symbol_name) => {
1544                         symbol_name != metadata_symbol_name
1545                     },
1546                     _ => true,
1547                 }
1548             })
1549             .cloned());
1550
1551         EncodedExportedSymbols {
1552             len: lazy_seq.len,
1553             position: lazy_seq.position,
1554         }
1555     }
1556
1557     fn encode_dylib_dependency_formats(&mut self, _: ()) -> LazySeq<Option<LinkagePreference>> {
1558         match self.tcx.sess.dependency_formats.borrow().get(&config::CrateType::Dylib) {
1559             Some(arr) => {
1560                 self.lazy_seq(arr.iter().map(|slot| {
1561                     match *slot {
1562                         Linkage::NotLinked |
1563                         Linkage::IncludedFromDylib => None,
1564
1565                         Linkage::Dynamic => Some(LinkagePreference::RequireDynamic),
1566                         Linkage::Static => Some(LinkagePreference::RequireStatic),
1567                     }
1568                 }))
1569             }
1570             None => LazySeq::empty(),
1571         }
1572     }
1573
1574     fn encode_info_for_foreign_item(&mut self,
1575                                     (def_id, nitem): (DefId, &hir::ForeignItem))
1576                                     -> Entry<'tcx> {
1577         let tcx = self.tcx;
1578
1579         debug!("IsolatedEncoder::encode_info_for_foreign_item({:?})", def_id);
1580
1581         let kind = match nitem.node {
1582             hir::ForeignItemKind::Fn(_, ref names, _) => {
1583                 let data = FnData {
1584                     constness: hir::Constness::NotConst,
1585                     arg_names: self.encode_fn_arg_names(names),
1586                     sig: self.lazy(&tcx.fn_sig(def_id)),
1587                 };
1588                 EntryKind::ForeignFn(self.lazy(&data))
1589             }
1590             hir::ForeignItemKind::Static(_, true) => EntryKind::ForeignMutStatic,
1591             hir::ForeignItemKind::Static(_, false) => EntryKind::ForeignImmStatic,
1592             hir::ForeignItemKind::Type => EntryKind::ForeignType,
1593         };
1594
1595         Entry {
1596             kind,
1597             visibility: self.lazy(&ty::Visibility::from_hir(&nitem.vis, nitem.id, tcx)),
1598             span: self.lazy(&nitem.span),
1599             attributes: self.encode_attributes(&nitem.attrs),
1600             children: LazySeq::empty(),
1601             stability: self.encode_stability(def_id),
1602             deprecation: self.encode_deprecation(def_id),
1603
1604             ty: Some(self.encode_item_type(def_id)),
1605             inherent_impls: LazySeq::empty(),
1606             variances: match nitem.node {
1607                 hir::ForeignItemKind::Fn(..) => self.encode_variances_of(def_id),
1608                 _ => LazySeq::empty(),
1609             },
1610             generics: Some(self.encode_generics(def_id)),
1611             predicates: Some(self.encode_predicates(def_id)),
1612             predicates_defined_on: None,
1613
1614             mir: None,
1615         }
1616     }
1617 }
1618
1619 struct EncodeVisitor<'a, 'b: 'a, 'tcx: 'b> {
1620     index: IndexBuilder<'a, 'b, 'tcx>,
1621 }
1622
1623 impl<'a, 'b, 'tcx> Visitor<'tcx> for EncodeVisitor<'a, 'b, 'tcx> {
1624     fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
1625         NestedVisitorMap::OnlyBodies(&self.index.tcx.hir)
1626     }
1627     fn visit_expr(&mut self, ex: &'tcx hir::Expr) {
1628         intravisit::walk_expr(self, ex);
1629         self.index.encode_info_for_expr(ex);
1630     }
1631     fn visit_item(&mut self, item: &'tcx hir::Item) {
1632         intravisit::walk_item(self, item);
1633         let def_id = self.index.tcx.hir.local_def_id(item.id);
1634         match item.node {
1635             hir::ItemKind::ExternCrate(_) |
1636             hir::ItemKind::Use(..) => (), // ignore these
1637             _ => self.index.record(def_id, IsolatedEncoder::encode_info_for_item, (def_id, item)),
1638         }
1639         self.index.encode_addl_info_for_item(item);
1640     }
1641     fn visit_foreign_item(&mut self, ni: &'tcx hir::ForeignItem) {
1642         intravisit::walk_foreign_item(self, ni);
1643         let def_id = self.index.tcx.hir.local_def_id(ni.id);
1644         self.index.record(def_id,
1645                           IsolatedEncoder::encode_info_for_foreign_item,
1646                           (def_id, ni));
1647     }
1648     fn visit_variant(&mut self,
1649                      v: &'tcx hir::Variant,
1650                      g: &'tcx hir::Generics,
1651                      id: ast::NodeId) {
1652         intravisit::walk_variant(self, v, g, id);
1653
1654         if let Some(ref discr) = v.node.disr_expr {
1655             let def_id = self.index.tcx.hir.local_def_id(discr.id);
1656             self.index.record(def_id, IsolatedEncoder::encode_info_for_anon_const, def_id);
1657         }
1658     }
1659     fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
1660         intravisit::walk_generics(self, generics);
1661         self.index.encode_info_for_generics(generics);
1662     }
1663     fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
1664         intravisit::walk_ty(self, ty);
1665         self.index.encode_info_for_ty(ty);
1666     }
1667     fn visit_macro_def(&mut self, macro_def: &'tcx hir::MacroDef) {
1668         let def_id = self.index.tcx.hir.local_def_id(macro_def.id);
1669         self.index.record(def_id, IsolatedEncoder::encode_info_for_macro_def, macro_def);
1670     }
1671 }
1672
1673 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
1674     fn encode_fields(&mut self, adt_def_id: DefId) {
1675         let def = self.tcx.adt_def(adt_def_id);
1676         for (variant_index, variant) in def.variants.iter().enumerate() {
1677             for (field_index, field) in variant.fields.iter().enumerate() {
1678                 self.record(field.did,
1679                             IsolatedEncoder::encode_field,
1680                             (adt_def_id, Untracked((variant_index, field_index))));
1681             }
1682         }
1683     }
1684
1685     fn encode_info_for_generics(&mut self, generics: &hir::Generics) {
1686         generics.params.iter().for_each(|param| match param.kind {
1687             hir::GenericParamKind::Lifetime { .. } => {}
1688             hir::GenericParamKind::Type { ref default, .. } => {
1689                 let def_id = self.tcx.hir.local_def_id(param.id);
1690                 let has_default = Untracked(default.is_some());
1691                 let encode_info = IsolatedEncoder::encode_info_for_ty_param;
1692                 self.record(def_id, encode_info, (def_id, has_default));
1693             }
1694         });
1695     }
1696
1697     fn encode_info_for_ty(&mut self, ty: &hir::Ty) {
1698         match ty.node {
1699             hir::TyKind::Array(_, ref length) => {
1700                 let def_id = self.tcx.hir.local_def_id(length.id);
1701                 self.record(def_id, IsolatedEncoder::encode_info_for_anon_const, def_id);
1702             }
1703             _ => {}
1704         }
1705     }
1706
1707     fn encode_info_for_expr(&mut self, expr: &hir::Expr) {
1708         match expr.node {
1709             hir::ExprKind::Closure(..) => {
1710                 let def_id = self.tcx.hir.local_def_id(expr.id);
1711                 self.record(def_id, IsolatedEncoder::encode_info_for_closure, def_id);
1712             }
1713             _ => {}
1714         }
1715     }
1716
1717     /// In some cases, along with the item itself, we also
1718     /// encode some sub-items. Usually we want some info from the item
1719     /// so it's easier to do that here then to wait until we would encounter
1720     /// normally in the visitor walk.
1721     fn encode_addl_info_for_item(&mut self, item: &hir::Item) {
1722         let def_id = self.tcx.hir.local_def_id(item.id);
1723         match item.node {
1724             hir::ItemKind::Static(..) |
1725             hir::ItemKind::Const(..) |
1726             hir::ItemKind::Fn(..) |
1727             hir::ItemKind::Mod(..) |
1728             hir::ItemKind::ForeignMod(..) |
1729             hir::ItemKind::GlobalAsm(..) |
1730             hir::ItemKind::ExternCrate(..) |
1731             hir::ItemKind::Use(..) |
1732             hir::ItemKind::Ty(..) |
1733             hir::ItemKind::Existential(..) |
1734             hir::ItemKind::TraitAlias(..) => {
1735                 // no sub-item recording needed in these cases
1736             }
1737             hir::ItemKind::Enum(..) => {
1738                 self.encode_fields(def_id);
1739
1740                 let def = self.tcx.adt_def(def_id);
1741                 for (i, variant) in def.variants.iter().enumerate() {
1742                     self.record(variant.did,
1743                                 IsolatedEncoder::encode_enum_variant_info,
1744                                 (def_id, Untracked(i)));
1745                 }
1746             }
1747             hir::ItemKind::Struct(ref struct_def, _) => {
1748                 self.encode_fields(def_id);
1749
1750                 // If the struct has a constructor, encode it.
1751                 if !struct_def.is_struct() {
1752                     let ctor_def_id = self.tcx.hir.local_def_id(struct_def.id());
1753                     self.record(ctor_def_id,
1754                                 IsolatedEncoder::encode_struct_ctor,
1755                                 (def_id, ctor_def_id));
1756                 }
1757             }
1758             hir::ItemKind::Union(..) => {
1759                 self.encode_fields(def_id);
1760             }
1761             hir::ItemKind::Impl(..) => {
1762                 for &trait_item_def_id in self.tcx.associated_item_def_ids(def_id).iter() {
1763                     self.record(trait_item_def_id,
1764                                 IsolatedEncoder::encode_info_for_impl_item,
1765                                 trait_item_def_id);
1766                 }
1767             }
1768             hir::ItemKind::Trait(..) => {
1769                 for &item_def_id in self.tcx.associated_item_def_ids(def_id).iter() {
1770                     self.record(item_def_id,
1771                                 IsolatedEncoder::encode_info_for_trait_item,
1772                                 item_def_id);
1773                 }
1774             }
1775         }
1776     }
1777 }
1778
1779 struct ImplVisitor<'a, 'tcx: 'a> {
1780     tcx: TyCtxt<'a, 'tcx, 'tcx>,
1781     impls: FxHashMap<DefId, Vec<DefIndex>>,
1782 }
1783
1784 impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for ImplVisitor<'a, 'tcx> {
1785     fn visit_item(&mut self, item: &hir::Item) {
1786         if let hir::ItemKind::Impl(..) = item.node {
1787             let impl_id = self.tcx.hir.local_def_id(item.id);
1788             if let Some(trait_ref) = self.tcx.impl_trait_ref(impl_id) {
1789                 self.impls
1790                     .entry(trait_ref.def_id)
1791                     .or_insert(vec![])
1792                     .push(impl_id.index);
1793             }
1794         }
1795     }
1796
1797     fn visit_trait_item(&mut self, _trait_item: &'v hir::TraitItem) {}
1798
1799     fn visit_impl_item(&mut self, _impl_item: &'v hir::ImplItem) {
1800         // handled in `visit_item` above
1801     }
1802 }
1803
1804 // NOTE(eddyb) The following comment was preserved for posterity, even
1805 // though it's no longer relevant as EBML (which uses nested & tagged
1806 // "documents") was replaced with a scheme that can't go out of bounds.
1807 //
1808 // And here we run into yet another obscure archive bug: in which metadata
1809 // loaded from archives may have trailing garbage bytes. Awhile back one of
1810 // our tests was failing sporadically on the macOS 64-bit builders (both nopt
1811 // and opt) by having ebml generate an out-of-bounds panic when looking at
1812 // metadata.
1813 //
1814 // Upon investigation it turned out that the metadata file inside of an rlib
1815 // (and ar archive) was being corrupted. Some compilations would generate a
1816 // metadata file which would end in a few extra bytes, while other
1817 // compilations would not have these extra bytes appended to the end. These
1818 // extra bytes were interpreted by ebml as an extra tag, so they ended up
1819 // being interpreted causing the out-of-bounds.
1820 //
1821 // The root cause of why these extra bytes were appearing was never
1822 // discovered, and in the meantime the solution we're employing is to insert
1823 // the length of the metadata to the start of the metadata. Later on this
1824 // will allow us to slice the metadata to the precise length that we just
1825 // generated regardless of trailing bytes that end up in it.
1826
1827 pub fn encode_metadata<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1828                                  link_meta: &LinkMeta)
1829                                  -> EncodedMetadata
1830 {
1831     let mut encoder = opaque::Encoder::new(vec![]);
1832     encoder.emit_raw_bytes(METADATA_HEADER);
1833
1834     // Will be filled with the root position after encoding everything.
1835     encoder.emit_raw_bytes(&[0, 0, 0, 0]);
1836
1837     let (root, mut result) = {
1838         let mut ecx = EncodeContext {
1839             opaque: encoder,
1840             tcx,
1841             link_meta,
1842             lazy_state: LazyState::NoNode,
1843             type_shorthands: Default::default(),
1844             predicate_shorthands: Default::default(),
1845             filemap_cache: tcx.sess.codemap().files()[0].clone(),
1846             interpret_allocs: Default::default(),
1847             interpret_allocs_inverse: Default::default(),
1848         };
1849
1850         // Encode the rustc version string in a predictable location.
1851         rustc_version().encode(&mut ecx).unwrap();
1852
1853         // Encode all the entries and extra information in the crate,
1854         // culminating in the `CrateRoot` which points to all of it.
1855         let root = ecx.encode_crate_root();
1856         (root, ecx.opaque.into_inner())
1857     };
1858
1859     // Encode the root position.
1860     let header = METADATA_HEADER.len();
1861     let pos = root.position;
1862     result[header + 0] = (pos >> 24) as u8;
1863     result[header + 1] = (pos >> 16) as u8;
1864     result[header + 2] = (pos >> 8) as u8;
1865     result[header + 3] = (pos >> 0) as u8;
1866
1867     EncodedMetadata { raw_data: result }
1868 }
1869
1870 pub fn get_repr_options<'a, 'tcx, 'gcx>(tcx: &TyCtxt<'a, 'tcx, 'gcx>, did: DefId) -> ReprOptions {
1871     let ty = tcx.type_of(did);
1872     match ty.sty {
1873         ty::TyAdt(ref def, _) => return def.repr,
1874         _ => bug!("{} is not an ADT", ty),
1875     }
1876 }