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.
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.
15 use rustc::middle::cstore::{LinkMeta, LinkagePreference, NativeLibrary};
16 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefIndex, DefId};
17 use rustc::hir::map::definitions::DefPathTable;
19 use rustc::middle::dependency_format::Linkage;
20 use rustc::middle::lang_items;
22 use rustc::traits::specialization_graph;
23 use rustc::ty::{self, Ty, TyCtxt, ReprOptions};
25 use rustc::session::config::{self, CrateTypeProcMacro};
26 use rustc::util::nodemap::{FxHashMap, NodeSet};
28 use rustc_serialize::{Encodable, Encoder, SpecializedEncoder, opaque};
31 use std::io::prelude::*;
35 use syntax::ast::{self, CRATE_NODE_ID};
36 use syntax::codemap::Spanned;
38 use syntax::symbol::Symbol;
39 use syntax_pos::{self, DUMMY_SP};
41 use rustc::hir::{self, PatKind};
42 use rustc::hir::itemlikevisit::ItemLikeVisitor;
43 use rustc::hir::intravisit::{Visitor, NestedVisitorMap};
44 use rustc::hir::intravisit;
46 use super::index_builder::{FromId, IndexBuilder, Untracked, EntryBuilder};
48 pub struct EncodeContext<'a, 'tcx: 'a> {
49 opaque: opaque::Encoder<'a>,
50 pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
51 link_meta: &'a LinkMeta,
52 cstore: &'a cstore::CStore,
53 exported_symbols: &'a NodeSet,
55 lazy_state: LazyState,
56 type_shorthands: FxHashMap<Ty<'tcx>, usize>,
57 predicate_shorthands: FxHashMap<ty::Predicate<'tcx>, usize>,
59 pub metadata_hashes: Vec<(DefIndex, ich::Fingerprint)>,
62 macro_rules! encoder_methods {
63 ($($name:ident($ty:ty);)*) => {
64 $(fn $name(&mut self, value: $ty) -> Result<(), Self::Error> {
65 self.opaque.$name(value)
70 impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
71 type Error = <opaque::Encoder<'a> as Encoder>::Error;
73 fn emit_nil(&mut self) -> Result<(), Self::Error> {
100 impl<'a, 'tcx, T> SpecializedEncoder<Lazy<T>> for EncodeContext<'a, 'tcx> {
101 fn specialized_encode(&mut self, lazy: &Lazy<T>) -> Result<(), Self::Error> {
102 self.emit_lazy_distance(lazy.position, Lazy::<T>::min_size())
106 impl<'a, 'tcx, T> SpecializedEncoder<LazySeq<T>> for EncodeContext<'a, 'tcx> {
107 fn specialized_encode(&mut self, seq: &LazySeq<T>) -> Result<(), Self::Error> {
108 self.emit_usize(seq.len)?;
112 self.emit_lazy_distance(seq.position, LazySeq::<T>::min_size(seq.len))
116 impl<'a, 'tcx> SpecializedEncoder<Ty<'tcx>> for EncodeContext<'a, 'tcx> {
117 fn specialized_encode(&mut self, ty: &Ty<'tcx>) -> Result<(), Self::Error> {
118 self.encode_with_shorthand(ty, &ty.sty, |ecx| &mut ecx.type_shorthands)
122 impl<'a, 'tcx> SpecializedEncoder<ty::GenericPredicates<'tcx>> for EncodeContext<'a, 'tcx> {
123 fn specialized_encode(&mut self,
124 predicates: &ty::GenericPredicates<'tcx>)
125 -> Result<(), Self::Error> {
126 predicates.parent.encode(self)?;
127 predicates.predicates.len().encode(self)?;
128 for predicate in &predicates.predicates {
129 self.encode_with_shorthand(predicate, predicate, |ecx| &mut ecx.predicate_shorthands)?
135 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
136 pub fn position(&self) -> usize {
137 self.opaque.position()
140 fn emit_node<F: FnOnce(&mut Self, usize) -> R, R>(&mut self, f: F) -> R {
141 assert_eq!(self.lazy_state, LazyState::NoNode);
142 let pos = self.position();
143 self.lazy_state = LazyState::NodeStart(pos);
144 let r = f(self, pos);
145 self.lazy_state = LazyState::NoNode;
149 fn emit_lazy_distance(&mut self,
152 -> Result<(), <Self as Encoder>::Error> {
153 let min_end = position + min_size;
154 let distance = match self.lazy_state {
155 LazyState::NoNode => bug!("emit_lazy_distance: outside of a metadata node"),
156 LazyState::NodeStart(start) => {
157 assert!(min_end <= start);
160 LazyState::Previous(last_min_end) => {
161 assert!(last_min_end <= position);
162 position - last_min_end
165 self.lazy_state = LazyState::Previous(min_end);
166 self.emit_usize(distance)
169 pub fn lazy<T: Encodable>(&mut self, value: &T) -> Lazy<T> {
170 self.emit_node(|ecx, pos| {
171 value.encode(ecx).unwrap();
173 assert!(pos + Lazy::<T>::min_size() <= ecx.position());
174 Lazy::with_position(pos)
178 pub fn lazy_seq<I, T>(&mut self, iter: I) -> LazySeq<T>
179 where I: IntoIterator<Item = T>,
182 self.emit_node(|ecx, pos| {
183 let len = iter.into_iter().map(|value| value.encode(ecx).unwrap()).count();
185 assert!(pos + LazySeq::<T>::min_size(len) <= ecx.position());
186 LazySeq::with_position_and_length(pos, len)
190 pub fn lazy_seq_ref<'b, I, T>(&mut self, iter: I) -> LazySeq<T>
191 where I: IntoIterator<Item = &'b T>,
194 self.emit_node(|ecx, pos| {
195 let len = iter.into_iter().map(|value| value.encode(ecx).unwrap()).count();
197 assert!(pos + LazySeq::<T>::min_size(len) <= ecx.position());
198 LazySeq::with_position_and_length(pos, len)
202 /// Encode the given value or a previously cached shorthand.
203 fn encode_with_shorthand<T, U, M>(&mut self,
207 -> Result<(), <Self as Encoder>::Error>
208 where M: for<'b> Fn(&'b mut Self) -> &'b mut FxHashMap<T, usize>,
209 T: Clone + Eq + Hash,
212 let existing_shorthand = map(self).get(value).cloned();
213 if let Some(shorthand) = existing_shorthand {
214 return self.emit_usize(shorthand);
217 let start = self.position();
218 variant.encode(self)?;
219 let len = self.position() - start;
221 // The shorthand encoding uses the same usize as the
222 // discriminant, with an offset so they can't conflict.
223 let discriminant = unsafe { intrinsics::discriminant_value(variant) };
224 assert!(discriminant < SHORTHAND_OFFSET as u64);
225 let shorthand = start + SHORTHAND_OFFSET;
227 // Get the number of bits that leb128 could fit
228 // in the same space as the fully encoded type.
229 let leb128_bits = len * 7;
231 // Check that the shorthand is a not longer than the
232 // full encoding itself, i.e. it's an obvious win.
233 if leb128_bits >= 64 || (shorthand as u64) < (1 << leb128_bits) {
234 map(self).insert(value.clone(), shorthand);
241 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
242 fn encode_item_variances(&mut self, def_id: DefId) -> LazySeq<ty::Variance> {
244 self.lazy_seq_from_slice(&tcx.item_variances(def_id))
247 fn encode_item_type(&mut self, def_id: DefId) -> Lazy<Ty<'tcx>> {
249 self.lazy(&tcx.item_type(def_id))
252 /// Encode data for the given variant of the given ADT. The
253 /// index of the variant is untracked: this is ok because we
254 /// will have to lookup the adt-def by its id, and that gives us
255 /// the right to access any information in the adt-def (including,
256 /// e.g., the length of the various vectors).
257 fn encode_enum_variant_info(&mut self,
258 (enum_did, Untracked(index)): (DefId, Untracked<usize>))
261 let def = tcx.lookup_adt_def(enum_did);
262 let variant = &def.variants[index];
263 let def_id = variant.did;
265 let data = VariantData {
266 ctor_kind: variant.ctor_kind,
267 discr: variant.discr,
268 evaluated_discr: match variant.discr {
269 ty::VariantDiscr::Explicit(def_id) => {
270 ty::queries::monomorphic_const_eval::get(tcx, DUMMY_SP, def_id).ok()
272 ty::VariantDiscr::Relative(_) => None
277 let enum_id = tcx.hir.as_local_node_id(enum_did).unwrap();
278 let enum_vis = &tcx.hir.expect_item(enum_id).vis;
281 kind: EntryKind::Variant(self.lazy(&data)),
282 visibility: self.lazy(&ty::Visibility::from_hir(enum_vis, enum_id, tcx)),
283 span: self.lazy(&tcx.def_span(def_id)),
284 attributes: self.encode_attributes(&tcx.get_attrs(def_id)),
285 children: self.lazy_seq(variant.fields.iter().map(|f| {
286 assert!(f.did.is_local());
289 stability: self.encode_stability(def_id),
290 deprecation: self.encode_deprecation(def_id),
292 ty: Some(self.encode_item_type(def_id)),
293 inherent_impls: LazySeq::empty(),
294 variances: LazySeq::empty(),
295 generics: Some(self.encode_generics(def_id)),
296 predicates: Some(self.encode_predicates(def_id)),
299 mir: self.encode_mir(def_id),
303 fn encode_info_for_mod(&mut self,
304 FromId(id, (md, attrs, vis)): FromId<(&hir::Mod,
309 let def_id = tcx.hir.local_def_id(id);
312 reexports: match tcx.export_map.get(&id) {
313 Some(exports) if *vis == hir::Public => {
314 self.lazy_seq_from_slice(exports.as_slice())
316 _ => LazySeq::empty(),
321 kind: EntryKind::Mod(self.lazy(&data)),
322 visibility: self.lazy(&ty::Visibility::from_hir(vis, id, tcx)),
323 span: self.lazy(&md.inner),
324 attributes: self.encode_attributes(attrs),
325 children: self.lazy_seq(md.item_ids.iter().map(|item_id| {
326 tcx.hir.local_def_id(item_id.id).index
328 stability: self.encode_stability(def_id),
329 deprecation: self.encode_deprecation(def_id),
332 inherent_impls: LazySeq::empty(),
333 variances: LazySeq::empty(),
343 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
344 fn encode_fields(&mut self, adt_def_id: DefId) {
345 let def = self.tcx.lookup_adt_def(adt_def_id);
346 for (variant_index, variant) in def.variants.iter().enumerate() {
347 for (field_index, field) in variant.fields.iter().enumerate() {
348 self.record(field.did,
349 EntryBuilder::encode_field,
350 (adt_def_id, Untracked((variant_index, field_index))));
356 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
357 /// Encode data for the given field of the given variant of the
358 /// given ADT. The indices of the variant/field are untracked:
359 /// this is ok because we will have to lookup the adt-def by its
360 /// id, and that gives us the right to access any information in
361 /// the adt-def (including, e.g., the length of the various
363 fn encode_field(&mut self,
364 (adt_def_id, Untracked((variant_index, field_index))): (DefId,
369 let variant = &tcx.lookup_adt_def(adt_def_id).variants[variant_index];
370 let field = &variant.fields[field_index];
372 let def_id = field.did;
373 let variant_id = tcx.hir.as_local_node_id(variant.did).unwrap();
374 let variant_data = tcx.hir.expect_variant_data(variant_id);
377 kind: EntryKind::Field,
378 visibility: self.lazy(&field.vis),
379 span: self.lazy(&tcx.def_span(def_id)),
380 attributes: self.encode_attributes(&variant_data.fields()[field_index].attrs),
381 children: LazySeq::empty(),
382 stability: self.encode_stability(def_id),
383 deprecation: self.encode_deprecation(def_id),
385 ty: Some(self.encode_item_type(def_id)),
386 inherent_impls: LazySeq::empty(),
387 variances: LazySeq::empty(),
388 generics: Some(self.encode_generics(def_id)),
389 predicates: Some(self.encode_predicates(def_id)),
396 fn encode_struct_ctor(&mut self, (adt_def_id, def_id): (DefId, DefId)) -> Entry<'tcx> {
398 let variant = tcx.lookup_adt_def(adt_def_id).struct_variant();
400 let data = VariantData {
401 ctor_kind: variant.ctor_kind,
402 discr: variant.discr,
403 evaluated_discr: None,
404 struct_ctor: Some(def_id.index),
407 let struct_id = tcx.hir.as_local_node_id(adt_def_id).unwrap();
408 let struct_vis = &tcx.hir.expect_item(struct_id).vis;
409 let mut ctor_vis = ty::Visibility::from_hir(struct_vis, struct_id, tcx);
410 for field in &variant.fields {
411 if ctor_vis.is_at_least(field.vis, tcx) {
412 ctor_vis = field.vis;
416 let repr_options = get_repr_options(&tcx, adt_def_id);
419 kind: EntryKind::Struct(self.lazy(&data), repr_options),
420 visibility: self.lazy(&ctor_vis),
421 span: self.lazy(&tcx.def_span(def_id)),
422 attributes: LazySeq::empty(),
423 children: LazySeq::empty(),
424 stability: self.encode_stability(def_id),
425 deprecation: self.encode_deprecation(def_id),
427 ty: Some(self.encode_item_type(def_id)),
428 inherent_impls: LazySeq::empty(),
429 variances: LazySeq::empty(),
430 generics: Some(self.encode_generics(def_id)),
431 predicates: Some(self.encode_predicates(def_id)),
434 mir: self.encode_mir(def_id),
438 fn encode_generics(&mut self, def_id: DefId) -> Lazy<ty::Generics> {
440 self.lazy(tcx.item_generics(def_id))
443 fn encode_predicates(&mut self, def_id: DefId) -> Lazy<ty::GenericPredicates<'tcx>> {
445 self.lazy(&tcx.item_predicates(def_id))
448 fn encode_info_for_trait_item(&mut self, def_id: DefId) -> Entry<'tcx> {
451 let node_id = tcx.hir.as_local_node_id(def_id).unwrap();
452 let ast_item = tcx.hir.expect_trait_item(node_id);
453 let trait_item = tcx.associated_item(def_id);
455 let container = match trait_item.defaultness {
456 hir::Defaultness::Default { has_value: true } =>
457 AssociatedContainer::TraitWithDefault,
458 hir::Defaultness::Default { has_value: false } =>
459 AssociatedContainer::TraitRequired,
460 hir::Defaultness::Final =>
461 span_bug!(ast_item.span, "traits cannot have final items"),
464 let kind = match trait_item.kind {
465 ty::AssociatedKind::Const => {
466 EntryKind::AssociatedConst(container, 0)
468 ty::AssociatedKind::Method => {
469 let fn_data = if let hir::TraitItemKind::Method(_, ref m) = ast_item.node {
470 let arg_names = match *m {
471 hir::TraitMethod::Required(ref names) => {
472 self.encode_fn_arg_names(names)
474 hir::TraitMethod::Provided(body) => {
475 self.encode_fn_arg_names_for_body(body)
479 constness: hir::Constness::NotConst,
485 EntryKind::Method(self.lazy(&MethodData {
487 container: container,
488 has_self: trait_item.method_has_self_argument,
491 ty::AssociatedKind::Type => EntryKind::AssociatedType(container),
496 visibility: self.lazy(&trait_item.vis),
497 span: self.lazy(&ast_item.span),
498 attributes: self.encode_attributes(&ast_item.attrs),
499 children: LazySeq::empty(),
500 stability: self.encode_stability(def_id),
501 deprecation: self.encode_deprecation(def_id),
503 ty: match trait_item.kind {
504 ty::AssociatedKind::Const |
505 ty::AssociatedKind::Method => {
506 Some(self.encode_item_type(def_id))
508 ty::AssociatedKind::Type => {
509 if trait_item.defaultness.has_value() {
510 Some(self.encode_item_type(def_id))
516 inherent_impls: LazySeq::empty(),
517 variances: LazySeq::empty(),
518 generics: Some(self.encode_generics(def_id)),
519 predicates: Some(self.encode_predicates(def_id)),
521 ast: if let hir::TraitItemKind::Const(_, Some(body)) = ast_item.node {
522 Some(self.encode_body(body))
526 mir: self.encode_mir(def_id),
530 fn encode_info_for_impl_item(&mut self, def_id: DefId) -> Entry<'tcx> {
531 let node_id = self.tcx.hir.as_local_node_id(def_id).unwrap();
532 let ast_item = self.tcx.hir.expect_impl_item(node_id);
533 let impl_item = self.tcx.associated_item(def_id);
535 let container = match impl_item.defaultness {
536 hir::Defaultness::Default { has_value: true } => AssociatedContainer::ImplDefault,
537 hir::Defaultness::Final => AssociatedContainer::ImplFinal,
538 hir::Defaultness::Default { has_value: false } =>
539 span_bug!(ast_item.span, "impl items always have values (currently)"),
542 let kind = match impl_item.kind {
543 ty::AssociatedKind::Const => {
544 EntryKind::AssociatedConst(container,
545 ty::queries::mir_const_qualif::get(self.tcx, ast_item.span, def_id))
547 ty::AssociatedKind::Method => {
548 let fn_data = if let hir::ImplItemKind::Method(ref sig, body) = ast_item.node {
550 constness: sig.constness,
551 arg_names: self.encode_fn_arg_names_for_body(body),
556 EntryKind::Method(self.lazy(&MethodData {
558 container: container,
559 has_self: impl_item.method_has_self_argument,
562 ty::AssociatedKind::Type => EntryKind::AssociatedType(container)
565 let (ast, mir) = if let hir::ImplItemKind::Const(_, body) = ast_item.node {
567 } else if let hir::ImplItemKind::Method(ref sig, body) = ast_item.node {
568 let generics = self.tcx.item_generics(def_id);
569 let types = generics.parent_types as usize + generics.types.len();
570 let needs_inline = types > 0 || attr::requests_inline(&ast_item.attrs);
571 let is_const_fn = sig.constness == hir::Constness::Const;
572 let ast = if is_const_fn { Some(body) } else { None };
573 let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
574 (ast, needs_inline || is_const_fn || always_encode_mir)
581 visibility: self.lazy(&impl_item.vis),
582 span: self.lazy(&ast_item.span),
583 attributes: self.encode_attributes(&ast_item.attrs),
584 children: LazySeq::empty(),
585 stability: self.encode_stability(def_id),
586 deprecation: self.encode_deprecation(def_id),
588 ty: Some(self.encode_item_type(def_id)),
589 inherent_impls: LazySeq::empty(),
590 variances: LazySeq::empty(),
591 generics: Some(self.encode_generics(def_id)),
592 predicates: Some(self.encode_predicates(def_id)),
594 ast: ast.map(|body| self.encode_body(body)),
595 mir: if mir { self.encode_mir(def_id) } else { None },
599 fn encode_fn_arg_names_for_body(&mut self, body_id: hir::BodyId)
600 -> LazySeq<ast::Name> {
601 let _ignore = self.tcx.dep_graph.in_ignore();
602 let body = self.tcx.hir.body(body_id);
603 self.lazy_seq(body.arguments.iter().map(|arg| {
605 PatKind::Binding(_, _, name, _) => name.node,
606 _ => Symbol::intern("")
611 fn encode_fn_arg_names(&mut self, names: &[Spanned<ast::Name>])
612 -> LazySeq<ast::Name> {
613 self.lazy_seq(names.iter().map(|name| name.node))
616 fn encode_mir(&mut self, def_id: DefId) -> Option<Lazy<mir::Mir<'tcx>>> {
617 self.tcx.maps.mir.borrow().get(&def_id).map(|mir| self.lazy(&*mir.borrow()))
620 // Encodes the inherent implementations of a structure, enumeration, or trait.
621 fn encode_inherent_implementations(&mut self, def_id: DefId) -> LazySeq<DefIndex> {
622 match self.tcx.maps.inherent_impls.borrow().get(&def_id) {
623 None => LazySeq::empty(),
624 Some(implementations) => {
625 self.lazy_seq(implementations.iter().map(|&def_id| {
626 assert!(def_id.is_local());
633 fn encode_stability(&mut self, def_id: DefId) -> Option<Lazy<attr::Stability>> {
634 self.tcx.lookup_stability(def_id).map(|stab| self.lazy(stab))
637 fn encode_deprecation(&mut self, def_id: DefId) -> Option<Lazy<attr::Deprecation>> {
638 self.tcx.lookup_deprecation(def_id).map(|depr| self.lazy(&depr))
641 fn encode_info_for_item(&mut self, (def_id, item): (DefId, &'tcx hir::Item)) -> Entry<'tcx> {
644 debug!("encoding info for item at {}",
645 tcx.sess.codemap().span_to_string(item.span));
647 let kind = match item.node {
648 hir::ItemStatic(_, hir::MutMutable, _) => EntryKind::MutStatic,
649 hir::ItemStatic(_, hir::MutImmutable, _) => EntryKind::ImmStatic,
650 hir::ItemConst(..) => {
651 EntryKind::Const(ty::queries::mir_const_qualif::get(tcx, item.span, def_id))
653 hir::ItemFn(_, _, constness, .., body) => {
655 constness: constness,
656 arg_names: self.encode_fn_arg_names_for_body(body),
659 EntryKind::Fn(self.lazy(&data))
661 hir::ItemMod(ref m) => {
662 return self.encode_info_for_mod(FromId(item.id, (m, &item.attrs, &item.vis)));
664 hir::ItemForeignMod(_) => EntryKind::ForeignMod,
665 hir::ItemTy(..) => EntryKind::Type,
666 hir::ItemEnum(..) => EntryKind::Enum(get_repr_options(&tcx, def_id)),
667 hir::ItemStruct(ref struct_def, _) => {
668 let variant = tcx.lookup_adt_def(def_id).struct_variant();
670 // Encode def_ids for each field and method
671 // for methods, write all the stuff get_trait_method
673 let struct_ctor = if !struct_def.is_struct() {
674 Some(tcx.hir.local_def_id(struct_def.id()).index)
679 let repr_options = get_repr_options(&tcx, def_id);
681 EntryKind::Struct(self.lazy(&VariantData {
682 ctor_kind: variant.ctor_kind,
683 discr: variant.discr,
684 evaluated_discr: None,
685 struct_ctor: struct_ctor,
688 hir::ItemUnion(..) => {
689 let variant = tcx.lookup_adt_def(def_id).struct_variant();
690 let repr_options = get_repr_options(&tcx, def_id);
692 EntryKind::Union(self.lazy(&VariantData {
693 ctor_kind: variant.ctor_kind,
694 discr: variant.discr,
695 evaluated_discr: None,
699 hir::ItemDefaultImpl(..) => {
700 let data = ImplData {
701 polarity: hir::ImplPolarity::Positive,
703 coerce_unsized_info: None,
704 trait_ref: tcx.impl_trait_ref(def_id).map(|trait_ref| self.lazy(&trait_ref)),
707 EntryKind::DefaultImpl(self.lazy(&data))
709 hir::ItemImpl(_, polarity, ..) => {
710 let trait_ref = tcx.impl_trait_ref(def_id);
711 let parent = if let Some(trait_ref) = trait_ref {
712 let trait_def = tcx.lookup_trait_def(trait_ref.def_id);
713 trait_def.ancestors(def_id).skip(1).next().and_then(|node| {
715 specialization_graph::Node::Impl(parent) => Some(parent),
723 // if this is an impl of `CoerceUnsized`, create its
724 // "unsized info", else just store None
725 let coerce_unsized_info =
726 trait_ref.and_then(|t| {
727 if Some(t.def_id) == tcx.lang_items.coerce_unsized_trait() {
728 Some(ty::queries::coerce_unsized_info::get(tcx, item.span, def_id))
734 let data = ImplData {
737 coerce_unsized_info: coerce_unsized_info,
738 trait_ref: trait_ref.map(|trait_ref| self.lazy(&trait_ref)),
741 EntryKind::Impl(self.lazy(&data))
743 hir::ItemTrait(..) => {
744 let trait_def = tcx.lookup_trait_def(def_id);
745 let data = TraitData {
746 unsafety: trait_def.unsafety,
747 paren_sugar: trait_def.paren_sugar,
748 has_default_impl: tcx.trait_has_default_impl(def_id),
749 super_predicates: self.lazy(&tcx.item_super_predicates(def_id)),
752 EntryKind::Trait(self.lazy(&data))
754 hir::ItemExternCrate(_) |
755 hir::ItemUse(..) => bug!("cannot encode info for item {:?}", item),
760 visibility: self.lazy(&ty::Visibility::from_hir(&item.vis, item.id, tcx)),
761 span: self.lazy(&item.span),
762 attributes: self.encode_attributes(&item.attrs),
763 children: match item.node {
764 hir::ItemForeignMod(ref fm) => {
765 self.lazy_seq(fm.items
767 .map(|foreign_item| tcx.hir.local_def_id(foreign_item.id).index))
769 hir::ItemEnum(..) => {
770 let def = self.tcx.lookup_adt_def(def_id);
771 self.lazy_seq(def.variants.iter().map(|v| {
772 assert!(v.did.is_local());
776 hir::ItemStruct(..) |
777 hir::ItemUnion(..) => {
778 let def = self.tcx.lookup_adt_def(def_id);
779 self.lazy_seq(def.struct_variant().fields.iter().map(|f| {
780 assert!(f.did.is_local());
785 hir::ItemTrait(..) => {
786 self.lazy_seq(tcx.associated_item_def_ids(def_id).iter().map(|&def_id| {
787 assert!(def_id.is_local());
791 _ => LazySeq::empty(),
793 stability: self.encode_stability(def_id),
794 deprecation: self.encode_deprecation(def_id),
796 ty: match item.node {
797 hir::ItemStatic(..) |
802 hir::ItemStruct(..) |
804 hir::ItemImpl(..) => Some(self.encode_item_type(def_id)),
807 inherent_impls: self.encode_inherent_implementations(def_id),
808 variances: match item.node {
810 hir::ItemStruct(..) |
812 hir::ItemTrait(..) => self.encode_item_variances(def_id),
813 _ => LazySeq::empty(),
815 generics: match item.node {
816 hir::ItemStatic(..) |
821 hir::ItemStruct(..) |
824 hir::ItemTrait(..) => Some(self.encode_generics(def_id)),
827 predicates: match item.node {
828 hir::ItemStatic(..) |
833 hir::ItemStruct(..) |
836 hir::ItemTrait(..) => Some(self.encode_predicates(def_id)),
840 ast: match item.node {
841 hir::ItemConst(_, body) |
842 hir::ItemFn(_, _, hir::Constness::Const, _, _, body) => {
843 Some(self.encode_body(body))
847 mir: match item.node {
848 hir::ItemStatic(..) if self.tcx.sess.opts.debugging_opts.always_encode_mir => {
849 self.encode_mir(def_id)
851 hir::ItemConst(..) => self.encode_mir(def_id),
852 hir::ItemFn(_, _, constness, _, ref generics, _) => {
853 let tps_len = generics.ty_params.len();
854 let needs_inline = tps_len > 0 || attr::requests_inline(&item.attrs);
855 let always_encode_mir = self.tcx.sess.opts.debugging_opts.always_encode_mir;
856 if needs_inline || constness == hir::Constness::Const || always_encode_mir {
857 self.encode_mir(def_id)
867 /// Serialize the text of exported macros
868 fn encode_info_for_macro_def(&mut self, macro_def: &hir::MacroDef) -> Entry<'tcx> {
869 use syntax::print::pprust;
871 kind: EntryKind::MacroDef(self.lazy(&MacroDef {
872 body: pprust::tts_to_string(¯o_def.body.trees().collect::<Vec<_>>()),
874 visibility: self.lazy(&ty::Visibility::Public),
875 span: self.lazy(¯o_def.span),
877 attributes: self.encode_attributes(¯o_def.attrs),
878 children: LazySeq::empty(),
882 inherent_impls: LazySeq::empty(),
883 variances: LazySeq::empty(),
892 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
893 /// In some cases, along with the item itself, we also
894 /// encode some sub-items. Usually we want some info from the item
895 /// so it's easier to do that here then to wait until we would encounter
896 /// normally in the visitor walk.
897 fn encode_addl_info_for_item(&mut self, item: &hir::Item) {
898 let def_id = self.tcx.hir.local_def_id(item.id);
900 hir::ItemStatic(..) |
904 hir::ItemForeignMod(..) |
905 hir::ItemExternCrate(..) |
907 hir::ItemDefaultImpl(..) |
909 // no sub-item recording needed in these cases
911 hir::ItemEnum(..) => {
912 self.encode_fields(def_id);
914 let def = self.tcx.lookup_adt_def(def_id);
915 for (i, variant) in def.variants.iter().enumerate() {
916 self.record(variant.did,
917 EntryBuilder::encode_enum_variant_info,
918 (def_id, Untracked(i)));
921 hir::ItemStruct(ref struct_def, _) => {
922 self.encode_fields(def_id);
924 // If the struct has a constructor, encode it.
925 if !struct_def.is_struct() {
926 let ctor_def_id = self.tcx.hir.local_def_id(struct_def.id());
927 self.record(ctor_def_id,
928 EntryBuilder::encode_struct_ctor,
929 (def_id, ctor_def_id));
932 hir::ItemUnion(..) => {
933 self.encode_fields(def_id);
935 hir::ItemImpl(..) => {
936 for &trait_item_def_id in self.tcx.associated_item_def_ids(def_id).iter() {
937 self.record(trait_item_def_id,
938 EntryBuilder::encode_info_for_impl_item,
942 hir::ItemTrait(..) => {
943 for &item_def_id in self.tcx.associated_item_def_ids(def_id).iter() {
944 self.record(item_def_id,
945 EntryBuilder::encode_info_for_trait_item,
953 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
954 fn encode_info_for_foreign_item(&mut self,
955 (def_id, nitem): (DefId, &hir::ForeignItem))
959 debug!("writing foreign item {}", tcx.node_path_str(nitem.id));
961 let kind = match nitem.node {
962 hir::ForeignItemFn(_, ref names, _) => {
964 constness: hir::Constness::NotConst,
965 arg_names: self.encode_fn_arg_names(names),
967 EntryKind::ForeignFn(self.lazy(&data))
969 hir::ForeignItemStatic(_, true) => EntryKind::ForeignMutStatic,
970 hir::ForeignItemStatic(_, false) => EntryKind::ForeignImmStatic,
975 visibility: self.lazy(&ty::Visibility::from_hir(&nitem.vis, nitem.id, tcx)),
976 span: self.lazy(&nitem.span),
977 attributes: self.encode_attributes(&nitem.attrs),
978 children: LazySeq::empty(),
979 stability: self.encode_stability(def_id),
980 deprecation: self.encode_deprecation(def_id),
982 ty: Some(self.encode_item_type(def_id)),
983 inherent_impls: LazySeq::empty(),
984 variances: LazySeq::empty(),
985 generics: Some(self.encode_generics(def_id)),
986 predicates: Some(self.encode_predicates(def_id)),
994 struct EncodeVisitor<'a, 'b: 'a, 'tcx: 'b> {
995 index: IndexBuilder<'a, 'b, 'tcx>,
998 impl<'a, 'b, 'tcx> Visitor<'tcx> for EncodeVisitor<'a, 'b, 'tcx> {
999 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
1000 NestedVisitorMap::OnlyBodies(&self.index.tcx.hir)
1002 fn visit_expr(&mut self, ex: &'tcx hir::Expr) {
1003 intravisit::walk_expr(self, ex);
1004 self.index.encode_info_for_expr(ex);
1006 fn visit_item(&mut self, item: &'tcx hir::Item) {
1007 intravisit::walk_item(self, item);
1008 let def_id = self.index.tcx.hir.local_def_id(item.id);
1010 hir::ItemExternCrate(_) |
1011 hir::ItemUse(..) => (), // ignore these
1012 _ => self.index.record(def_id, EntryBuilder::encode_info_for_item, (def_id, item)),
1014 self.index.encode_addl_info_for_item(item);
1016 fn visit_foreign_item(&mut self, ni: &'tcx hir::ForeignItem) {
1017 intravisit::walk_foreign_item(self, ni);
1018 let def_id = self.index.tcx.hir.local_def_id(ni.id);
1019 self.index.record(def_id,
1020 EntryBuilder::encode_info_for_foreign_item,
1023 fn visit_generics(&mut self, generics: &'tcx hir::Generics) {
1024 intravisit::walk_generics(self, generics);
1025 self.index.encode_info_for_generics(generics);
1027 fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
1028 intravisit::walk_ty(self, ty);
1029 self.index.encode_info_for_ty(ty);
1031 fn visit_macro_def(&mut self, macro_def: &'tcx hir::MacroDef) {
1032 let def_id = self.index.tcx.hir.local_def_id(macro_def.id);
1033 self.index.record(def_id, EntryBuilder::encode_info_for_macro_def, macro_def);
1037 impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
1038 fn encode_info_for_generics(&mut self, generics: &hir::Generics) {
1039 for ty_param in &generics.ty_params {
1040 let def_id = self.tcx.hir.local_def_id(ty_param.id);
1041 let has_default = Untracked(ty_param.default.is_some());
1042 self.record(def_id, EntryBuilder::encode_info_for_ty_param, (def_id, has_default));
1046 fn encode_info_for_ty(&mut self, ty: &hir::Ty) {
1047 if let hir::TyImplTrait(_) = ty.node {
1048 let def_id = self.tcx.hir.local_def_id(ty.id);
1049 self.record(def_id, EntryBuilder::encode_info_for_anon_ty, def_id);
1053 fn encode_info_for_expr(&mut self, expr: &hir::Expr) {
1055 hir::ExprClosure(..) => {
1056 let def_id = self.tcx.hir.local_def_id(expr.id);
1057 self.record(def_id, EntryBuilder::encode_info_for_closure, def_id);
1064 impl<'a, 'b: 'a, 'tcx: 'b> EntryBuilder<'a, 'b, 'tcx> {
1065 fn encode_info_for_ty_param(&mut self,
1066 (def_id, Untracked(has_default)): (DefId, Untracked<bool>))
1070 kind: EntryKind::Type,
1071 visibility: self.lazy(&ty::Visibility::Public),
1072 span: self.lazy(&tcx.def_span(def_id)),
1073 attributes: LazySeq::empty(),
1074 children: LazySeq::empty(),
1078 ty: if has_default {
1079 Some(self.encode_item_type(def_id))
1083 inherent_impls: LazySeq::empty(),
1084 variances: LazySeq::empty(),
1093 fn encode_info_for_anon_ty(&mut self, def_id: DefId) -> Entry<'tcx> {
1096 kind: EntryKind::Type,
1097 visibility: self.lazy(&ty::Visibility::Public),
1098 span: self.lazy(&tcx.def_span(def_id)),
1099 attributes: LazySeq::empty(),
1100 children: LazySeq::empty(),
1104 ty: Some(self.encode_item_type(def_id)),
1105 inherent_impls: LazySeq::empty(),
1106 variances: LazySeq::empty(),
1107 generics: Some(self.encode_generics(def_id)),
1108 predicates: Some(self.encode_predicates(def_id)),
1115 fn encode_info_for_closure(&mut self, def_id: DefId) -> Entry<'tcx> {
1118 let data = ClosureData {
1119 kind: tcx.closure_kind(def_id),
1120 ty: self.lazy(&tcx.closure_type(def_id)),
1124 kind: EntryKind::Closure(self.lazy(&data)),
1125 visibility: self.lazy(&ty::Visibility::Public),
1126 span: self.lazy(&tcx.def_span(def_id)),
1127 attributes: self.encode_attributes(&tcx.get_attrs(def_id)),
1128 children: LazySeq::empty(),
1132 ty: Some(self.encode_item_type(def_id)),
1133 inherent_impls: LazySeq::empty(),
1134 variances: LazySeq::empty(),
1135 generics: Some(self.encode_generics(def_id)),
1139 mir: self.encode_mir(def_id),
1143 fn encode_attributes(&mut self, attrs: &[ast::Attribute]) -> LazySeq<ast::Attribute> {
1144 self.lazy_seq_from_slice(attrs)
1148 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
1149 fn encode_info_for_items(&mut self) -> Index {
1150 let krate = self.tcx.hir.krate();
1151 let mut index = IndexBuilder::new(self);
1152 index.record(DefId::local(CRATE_DEF_INDEX),
1153 EntryBuilder::encode_info_for_mod,
1154 FromId(CRATE_NODE_ID, (&krate.module, &krate.attrs, &hir::Public)));
1155 let mut visitor = EncodeVisitor { index: index };
1156 krate.visit_all_item_likes(&mut visitor.as_deep_visitor());
1157 for macro_def in &krate.exported_macros {
1158 visitor.visit_macro_def(macro_def);
1160 visitor.index.into_items()
1163 fn encode_crate_deps(&mut self) -> LazySeq<CrateDep> {
1164 fn get_ordered_deps(cstore: &cstore::CStore) -> Vec<(CrateNum, Rc<cstore::CrateMetadata>)> {
1165 // Pull the cnums and name,vers,hash out of cstore
1166 let mut deps = Vec::new();
1167 cstore.iter_crate_data(|cnum, val| {
1168 deps.push((cnum, val.clone()));
1172 deps.sort_by(|kv1, kv2| kv1.0.cmp(&kv2.0));
1174 // Sanity-check the crate numbers
1175 let mut expected_cnum = 1;
1176 for &(n, _) in &deps {
1177 assert_eq!(n, CrateNum::new(expected_cnum));
1184 // We're just going to write a list of crate 'name-hash-version's, with
1185 // the assumption that they are numbered 1 to n.
1186 // FIXME (#2166): This is not nearly enough to support correct versioning
1187 // but is enough to get transitive crate dependencies working.
1188 let deps = get_ordered_deps(self.cstore);
1189 self.lazy_seq(deps.iter().map(|&(_, ref dep)| {
1193 kind: dep.dep_kind.get(),
1198 fn encode_lang_items(&mut self) -> (LazySeq<(DefIndex, usize)>, LazySeq<lang_items::LangItem>) {
1200 let lang_items = tcx.lang_items.items().iter();
1201 (self.lazy_seq(lang_items.enumerate().filter_map(|(i, &opt_def_id)| {
1202 if let Some(def_id) = opt_def_id {
1203 if def_id.is_local() {
1204 return Some((def_id.index, i));
1209 self.lazy_seq_ref(&tcx.lang_items.missing))
1212 fn encode_native_libraries(&mut self) -> LazySeq<NativeLibrary> {
1213 let used_libraries = self.tcx.sess.cstore.used_libraries();
1214 self.lazy_seq(used_libraries)
1217 fn encode_codemap(&mut self) -> LazySeq<syntax_pos::FileMap> {
1218 let codemap = self.tcx.sess.codemap();
1219 let all_filemaps = codemap.files.borrow();
1220 self.lazy_seq_ref(all_filemaps.iter()
1222 // No need to re-export imported filemaps, as any downstream
1223 // crate will import them from their original source.
1224 !filemap.is_imported()
1226 .map(|filemap| &**filemap))
1229 fn encode_def_path_table(&mut self) -> Lazy<DefPathTable> {
1230 let definitions = self.tcx.hir.definitions();
1231 self.lazy(definitions.def_path_table())
1235 struct ImplVisitor<'a, 'tcx: 'a> {
1236 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1237 impls: FxHashMap<DefId, Vec<DefIndex>>,
1240 impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for ImplVisitor<'a, 'tcx> {
1241 fn visit_item(&mut self, item: &hir::Item) {
1242 if let hir::ItemImpl(..) = item.node {
1243 let impl_id = self.tcx.hir.local_def_id(item.id);
1244 if let Some(trait_ref) = self.tcx.impl_trait_ref(impl_id) {
1246 .entry(trait_ref.def_id)
1248 .push(impl_id.index);
1253 fn visit_trait_item(&mut self, _trait_item: &'v hir::TraitItem) {}
1255 fn visit_impl_item(&mut self, _impl_item: &'v hir::ImplItem) {
1256 // handled in `visit_item` above
1260 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
1261 /// Encodes an index, mapping each trait to its (local) implementations.
1262 fn encode_impls(&mut self) -> LazySeq<TraitImpls> {
1263 let mut visitor = ImplVisitor {
1267 self.tcx.hir.krate().visit_all_item_likes(&mut visitor);
1269 let all_impls: Vec<_> = visitor.impls
1271 .map(|(trait_def_id, impls)| {
1273 trait_id: (trait_def_id.krate.as_u32(), trait_def_id.index),
1274 impls: self.lazy_seq(impls),
1279 self.lazy_seq(all_impls)
1282 // Encodes all symbols exported from this crate into the metadata.
1284 // This pass is seeded off the reachability list calculated in the
1285 // middle::reachable module but filters out items that either don't have a
1286 // symbol associated with them (they weren't translated) or if they're an FFI
1287 // definition (as that's not defined in this crate).
1288 fn encode_exported_symbols(&mut self) -> LazySeq<DefIndex> {
1289 let exported_symbols = self.exported_symbols;
1291 self.lazy_seq(exported_symbols.iter().map(|&id| tcx.hir.local_def_id(id).index))
1294 fn encode_dylib_dependency_formats(&mut self) -> LazySeq<Option<LinkagePreference>> {
1295 match self.tcx.sess.dependency_formats.borrow().get(&config::CrateTypeDylib) {
1297 self.lazy_seq(arr.iter().map(|slot| {
1299 Linkage::NotLinked |
1300 Linkage::IncludedFromDylib => None,
1302 Linkage::Dynamic => Some(LinkagePreference::RequireDynamic),
1303 Linkage::Static => Some(LinkagePreference::RequireStatic),
1307 None => LazySeq::empty(),
1312 impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
1313 fn encode_crate_root(&mut self) -> Lazy<CrateRoot> {
1314 let mut i = self.position();
1315 let crate_deps = self.encode_crate_deps();
1316 let dylib_dependency_formats = self.encode_dylib_dependency_formats();
1317 let dep_bytes = self.position() - i;
1319 // Encode the language items.
1320 i = self.position();
1321 let (lang_items, lang_items_missing) = self.encode_lang_items();
1322 let lang_item_bytes = self.position() - i;
1324 // Encode the native libraries used
1325 i = self.position();
1326 let native_libraries = self.encode_native_libraries();
1327 let native_lib_bytes = self.position() - i;
1330 i = self.position();
1331 let codemap = self.encode_codemap();
1332 let codemap_bytes = self.position() - i;
1334 // Encode DefPathTable
1335 i = self.position();
1336 let def_path_table = self.encode_def_path_table();
1337 let def_path_table_bytes = self.position() - i;
1339 // Encode the def IDs of impls, for coherence checking.
1340 i = self.position();
1341 let impls = self.encode_impls();
1342 let impl_bytes = self.position() - i;
1344 // Encode exported symbols info.
1345 i = self.position();
1346 let exported_symbols = self.encode_exported_symbols();
1347 let exported_symbols_bytes = self.position() - i;
1349 // Encode and index the items.
1350 i = self.position();
1351 let items = self.encode_info_for_items();
1352 let item_bytes = self.position() - i;
1354 i = self.position();
1355 let index = items.write_index(&mut self.opaque.cursor);
1356 let index_bytes = self.position() - i;
1359 let link_meta = self.link_meta;
1360 let is_proc_macro = tcx.sess.crate_types.borrow().contains(&CrateTypeProcMacro);
1361 let root = self.lazy(&CrateRoot {
1362 name: link_meta.crate_name,
1363 triple: tcx.sess.opts.target_triple.clone(),
1364 hash: link_meta.crate_hash,
1365 disambiguator: tcx.sess.local_crate_disambiguator(),
1366 panic_strategy: tcx.sess.panic_strategy(),
1367 plugin_registrar_fn: tcx.sess
1368 .plugin_registrar_fn
1370 .map(|id| tcx.hir.local_def_id(id).index),
1371 macro_derive_registrar: if is_proc_macro {
1372 let id = tcx.sess.derive_registrar_fn.get().unwrap();
1373 Some(tcx.hir.local_def_id(id).index)
1378 crate_deps: crate_deps,
1379 dylib_dependency_formats: dylib_dependency_formats,
1380 lang_items: lang_items,
1381 lang_items_missing: lang_items_missing,
1382 native_libraries: native_libraries,
1384 def_path_table: def_path_table,
1386 exported_symbols: exported_symbols,
1390 let total_bytes = self.position();
1392 if self.tcx.sess.meta_stats() {
1393 let mut zero_bytes = 0;
1394 for e in self.opaque.cursor.get_ref() {
1400 println!("metadata stats:");
1401 println!(" dep bytes: {}", dep_bytes);
1402 println!(" lang item bytes: {}", lang_item_bytes);
1403 println!(" native bytes: {}", native_lib_bytes);
1404 println!(" codemap bytes: {}", codemap_bytes);
1405 println!(" impl bytes: {}", impl_bytes);
1406 println!(" exp. symbols bytes: {}", exported_symbols_bytes);
1407 println!(" def-path table bytes: {}", def_path_table_bytes);
1408 println!(" item bytes: {}", item_bytes);
1409 println!(" index bytes: {}", index_bytes);
1410 println!(" zero bytes: {}", zero_bytes);
1411 println!(" total bytes: {}", total_bytes);
1418 // NOTE(eddyb) The following comment was preserved for posterity, even
1419 // though it's no longer relevant as EBML (which uses nested & tagged
1420 // "documents") was replaced with a scheme that can't go out of bounds.
1422 // And here we run into yet another obscure archive bug: in which metadata
1423 // loaded from archives may have trailing garbage bytes. Awhile back one of
1424 // our tests was failing sporadically on the macOS 64-bit builders (both nopt
1425 // and opt) by having ebml generate an out-of-bounds panic when looking at
1428 // Upon investigation it turned out that the metadata file inside of an rlib
1429 // (and ar archive) was being corrupted. Some compilations would generate a
1430 // metadata file which would end in a few extra bytes, while other
1431 // compilations would not have these extra bytes appended to the end. These
1432 // extra bytes were interpreted by ebml as an extra tag, so they ended up
1433 // being interpreted causing the out-of-bounds.
1435 // The root cause of why these extra bytes were appearing was never
1436 // discovered, and in the meantime the solution we're employing is to insert
1437 // the length of the metadata to the start of the metadata. Later on this
1438 // will allow us to slice the metadata to the precise length that we just
1439 // generated regardless of trailing bytes that end up in it.
1441 pub fn encode_metadata<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1442 cstore: &cstore::CStore,
1443 link_meta: &LinkMeta,
1444 exported_symbols: &NodeSet)
1446 let mut cursor = Cursor::new(vec![]);
1447 cursor.write_all(METADATA_HEADER).unwrap();
1449 // Will be filed with the root position after encoding everything.
1450 cursor.write_all(&[0, 0, 0, 0]).unwrap();
1453 let mut ecx = EncodeContext {
1454 opaque: opaque::Encoder::new(&mut cursor),
1456 link_meta: link_meta,
1458 exported_symbols: exported_symbols,
1459 lazy_state: LazyState::NoNode,
1460 type_shorthands: Default::default(),
1461 predicate_shorthands: Default::default(),
1462 metadata_hashes: Vec::new(),
1465 // Encode the rustc version string in a predictable location.
1466 rustc_version().encode(&mut ecx).unwrap();
1468 // Encode all the entries and extra information in the crate,
1469 // culminating in the `CrateRoot` which points to all of it.
1470 ecx.encode_crate_root()
1472 let mut result = cursor.into_inner();
1474 // Encode the root position.
1475 let header = METADATA_HEADER.len();
1476 let pos = root.position;
1477 result[header + 0] = (pos >> 24) as u8;
1478 result[header + 1] = (pos >> 16) as u8;
1479 result[header + 2] = (pos >> 8) as u8;
1480 result[header + 3] = (pos >> 0) as u8;
1485 pub fn get_repr_options<'a, 'tcx, 'gcx>(tcx: &TyCtxt<'a, 'tcx, 'gcx>, did: DefId) -> ReprOptions {
1486 let ty = tcx.item_type(did);
1488 ty::TyAdt(ref def, _) => return def.repr,
1489 _ => bug!("{} is not an ADT", ty),