Rollup merge of #66496 - petrochenkov:metapriv2, r=eddyb

rustc_metadata: Privatize more things

Continuation of https://github.com/rust-lang/rust/pull/66056.

The most notable change here is that `CrateMetadata` is moved from `cstore.rs` to `decoder.rs`.
Most of uses of `CrateMetadata` fields are in the decoder and uses of `root: CrateRoot` and other fields are so intertwined with each other that it would be hard to move a part of them into `cstore.rs` to privatize `CrateMetadata` fields, so we are going the other way round.

`cstore.rs` can probably be dismantled now, but I'll leave this to some other day.
Similarly, remaining `CrateMetadata` fields can be privatized by introducing some getter/setter methods, but not today.

r? @eddyb

6 files changed, 343 insertions, 282 deletions

diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index 6dfb2409775..a721e381b4e 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -1,21 +1,17 @@
 //! Validates all used crates and extern libraries and loads their metadata
 
-use crate::cstore::{self, CStore, MetadataBlob};
-use crate::locator::{self, CratePaths};
-use crate::rmeta::{CrateRoot, CrateDep};
-use rustc_data_structures::sync::{Lock, Once, AtomicCell};
+use crate::cstore::CStore;
+use crate::locator::{CrateLocator, CratePaths};
+use crate::rmeta::{CrateMetadata, CrateNumMap, CrateRoot, CrateDep, MetadataBlob};
 
 use rustc::hir::def_id::CrateNum;
 use rustc_data_structures::svh::Svh;
-use rustc::dep_graph::DepNodeIndex;
 use rustc::middle::cstore::DepKind;
-use rustc::mir::interpret::AllocDecodingState;
 use rustc::session::{Session, CrateDisambiguator};
 use rustc::session::config::{Sanitizer, self};
 use rustc_target::spec::{PanicStrategy, TargetTriple};
 use rustc::session::search_paths::PathKind;
 use rustc::middle::cstore::{CrateSource, ExternCrate, ExternCrateSource, MetadataLoaderDyn};
-use rustc::util::common::record_time;
 use rustc::util::nodemap::FxHashSet;
 use rustc::hir::map::Definitions;
 use rustc::hir::def_id::LOCAL_CRATE;
@@ -50,9 +46,9 @@ pub struct CrateLoader<'a> {
 
 fn dump_crates(cstore: &CStore) {
     info!("resolved crates:");
-    cstore.iter_crate_data(|_, data| {
+    cstore.iter_crate_data(|cnum, data| {
         info!("  name: {}", data.root.name);
-        info!("  cnum: {}", data.cnum);
+        info!("  cnum: {}", cnum);
         info!("  hash: {}", data.root.hash);
         info!("  reqd: {:?}", *data.dep_kind.lock());
         let CrateSource { dylib, rlib, rmeta } = data.source.clone();
@@ -68,13 +64,13 @@ enum LoadResult {
 }
 
 enum LoadError<'a> {
-    LocatorError(locator::Context<'a>),
+    LocatorError(CrateLocator<'a>),
 }
 
 impl<'a> LoadError<'a> {
     fn report(self) -> ! {
         match self {
-            LoadError::LocatorError(locate_ctxt) => locate_ctxt.report_errs(),
+            LoadError::LocatorError(locator) => locator.report_errs(),
         }
     }
 }
@@ -145,7 +141,7 @@ impl<'a> CrateLoader<'a> {
             let prev_kind = source.dylib.as_ref().or(source.rlib.as_ref())
                                   .or(source.rmeta.as_ref())
                                   .expect("No sources for crate").1;
-            if ret.is_none() && (prev_kind == kind || prev_kind == PathKind::All) {
+            if kind.matches(prev_kind) {
                 ret = Some(cnum);
             }
         });
@@ -211,15 +207,13 @@ impl<'a> CrateLoader<'a> {
         let root = if let Some(root) = root {
             root
         } else {
-            crate_paths = CratePaths { name: crate_root.name, source: source.clone() };
+            crate_paths = CratePaths::new(crate_root.name, source.clone());
             &crate_paths
         };
 
         let cnum_map = self.resolve_crate_deps(root, &crate_root, &metadata, cnum, span, dep_kind);
 
-        let dependencies: Vec<CrateNum> = cnum_map.iter().cloned().collect();
-
-        let raw_proc_macros =  crate_root.proc_macro_data.map(|_| {
+        let raw_proc_macros = if crate_root.is_proc_macro_crate() {
             let temp_root;
             let (dlsym_source, dlsym_root) = match &host_lib {
                 Some(host_lib) =>
@@ -227,55 +221,38 @@ impl<'a> CrateLoader<'a> {
                 None => (&source, &crate_root),
             };
             let dlsym_dylib = dlsym_source.dylib.as_ref().expect("no dylib for a proc-macro crate");
-            self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator, span)
-        });
-
-        let interpret_alloc_index: Vec<u32> = crate_root.interpret_alloc_index
-                                                        .decode(&metadata)
-                                                        .collect();
-        let trait_impls = crate_root
-            .impls
-            .decode((&metadata, self.sess))
-            .map(|trait_impls| (trait_impls.trait_id, trait_impls.impls))
-            .collect();
-
-        let def_path_table = record_time(&self.sess.perf_stats.decode_def_path_tables_time, || {
-            crate_root.def_path_table.decode((&metadata, self.sess))
-        });
+            Some(self.dlsym_proc_macros(&dlsym_dylib.0, dlsym_root.disambiguator, span))
+        } else {
+            None
+        };
 
-        self.cstore.set_crate_data(cnum, cstore::CrateMetadata {
-            extern_crate: Lock::new(None),
-            def_path_table,
-            trait_impls,
-            root: crate_root,
-            host_hash,
-            blob: metadata,
-            cnum_map,
+        self.cstore.set_crate_data(cnum, CrateMetadata::new(
+            self.sess,
+            metadata,
+            crate_root,
+            raw_proc_macros,
             cnum,
-            dependencies: Lock::new(dependencies),
-            source_map_import_info: Once::new(),
-            alloc_decoding_state: AllocDecodingState::new(interpret_alloc_index),
-            dep_kind: Lock::new(dep_kind),
+            cnum_map,
+            dep_kind,
             source,
             private_dep,
-            raw_proc_macros,
-            dep_node_index: AtomicCell::new(DepNodeIndex::INVALID),
-        });
+            host_hash,
+        ));
 
         cnum
     }
 
     fn load_proc_macro<'b>(
         &self,
-        locate_ctxt: &mut locator::Context<'b>,
+        locator: &mut CrateLocator<'b>,
         path_kind: PathKind,
     ) -> Option<(LoadResult, Option<Library>)>
     where
         'a: 'b,
     {
-        // Use a new locator Context so trying to load a proc macro doesn't affect the error
+        // Use a new crate locator so trying to load a proc macro doesn't affect the error
         // message we emit
-        let mut proc_macro_locator = locate_ctxt.clone();
+        let mut proc_macro_locator = locator.clone();
 
         // Try to load a proc macro
         proc_macro_locator.is_proc_macro = Some(true);
@@ -287,10 +264,10 @@ impl<'a> CrateLoader<'a> {
                 LoadResult::Previous(cnum) => return Some((LoadResult::Previous(cnum), None)),
                 LoadResult::Loaded(library) => Some(LoadResult::Loaded(library))
             };
-            locate_ctxt.hash = locate_ctxt.host_hash;
-            // Use the locate_ctxt when looking for the host proc macro crate, as that is required
+            locator.hash = locator.host_hash;
+            // Use the locator when looking for the host proc macro crate, as that is required
             // so we want it to affect the error message
-            (locate_ctxt, result)
+            (locator, result)
         } else {
             (&mut proc_macro_locator, None)
         };
@@ -350,37 +327,30 @@ impl<'a> CrateLoader<'a> {
             (LoadResult::Previous(cnum), None)
         } else {
             info!("falling back to a load");
-            let mut locate_ctxt = locator::Context {
-                sess: self.sess,
-                span,
-                crate_name: name,
+            let mut locator = CrateLocator::new(
+                self.sess,
+                self.metadata_loader,
+                name,
                 hash,
                 host_hash,
                 extra_filename,
-                filesearch: self.sess.target_filesearch(path_kind),
-                target: &self.sess.target.target,
-                triple: self.sess.opts.target_triple.clone(),
+                false, // is_host
+                path_kind,
+                span,
                 root,
-                rejected_via_hash: vec![],
-                rejected_via_triple: vec![],
-                rejected_via_kind: vec![],
-                rejected_via_version: vec![],
-                rejected_via_filename: vec![],
-                should_match_name: true,
-                is_proc_macro: Some(false),
-                metadata_loader: self.metadata_loader,
-            };
+                Some(false), // is_proc_macro
+            );
 
-            self.load(&mut locate_ctxt).map(|r| (r, None)).or_else(|| {
+            self.load(&mut locator).map(|r| (r, None)).or_else(|| {
                 dep_kind = DepKind::UnexportedMacrosOnly;
-                self.load_proc_macro(&mut locate_ctxt, path_kind)
-            }).ok_or_else(move || LoadError::LocatorError(locate_ctxt))?
+                self.load_proc_macro(&mut locator, path_kind)
+            }).ok_or_else(move || LoadError::LocatorError(locator))?
         };
 
         match result {
             (LoadResult::Previous(cnum), None) => {
                 let data = self.cstore.get_crate_data(cnum);
-                if data.root.proc_macro_data.is_some() {
+                if data.root.is_proc_macro_crate() {
                     dep_kind = DepKind::UnexportedMacrosOnly;
                 }
                 data.dep_kind.with_lock(|data_dep_kind| {
@@ -395,8 +365,8 @@ impl<'a> CrateLoader<'a> {
         }
     }
 
-    fn load(&self, locate_ctxt: &mut locator::Context<'_>) -> Option<LoadResult> {
-        let library = locate_ctxt.maybe_load_library_crate()?;
+    fn load(&self, locator: &mut CrateLocator<'_>) -> Option<LoadResult> {
+        let library = locator.maybe_load_library_crate()?;
 
         // In the case that we're loading a crate, but not matching
         // against a hash, we could load a crate which has the same hash
@@ -407,11 +377,11 @@ impl<'a> CrateLoader<'a> {
         // don't want to match a host crate against an equivalent target one
         // already loaded.
         let root = library.metadata.get_root();
-        if locate_ctxt.triple == self.sess.opts.target_triple {
+        if locator.triple == self.sess.opts.target_triple {
             let mut result = LoadResult::Loaded(library);
             self.cstore.iter_crate_data(|cnum, data| {
                 if data.root.name == root.name && root.hash == data.root.hash {
-                    assert!(locate_ctxt.hash.is_none());
+                    assert!(locator.hash.is_none());
                     info!("load success, going to previous cnum: {}", cnum);
                     result = LoadResult::Previous(cnum);
                 }
@@ -471,16 +441,16 @@ impl<'a> CrateLoader<'a> {
                           krate: CrateNum,
                           span: Span,
                           dep_kind: DepKind)
-                          -> cstore::CrateNumMap {
+                          -> CrateNumMap {
         debug!("resolving deps of external crate");
-        if crate_root.proc_macro_data.is_some() {
-            return cstore::CrateNumMap::new();
+        if crate_root.is_proc_macro_crate() {
+            return CrateNumMap::new();
         }
 
         // The map from crate numbers in the crate we're resolving to local crate numbers.
         // We map 0 and all other holes in the map to our parent crate. The "additional"
         // self-dependencies should be harmless.
-        std::iter::once(krate).chain(crate_root.crate_deps.decode(metadata).map(|dep| {
+        std::iter::once(krate).chain(crate_root.decode_crate_deps(metadata).map(|dep| {
             info!("resolving dep crate {} hash: `{}` extra filename: `{}`", dep.name, dep.hash,
                   dep.extra_filename);
             if dep.kind == DepKind::UnexportedMacrosOnly {
@@ -824,7 +794,7 @@ impl<'a> CrateLoader<'a> {
     fn inject_dependency_if(&self,
                             krate: CrateNum,
                             what: &str,
-                            needs_dep: &dyn Fn(&cstore::CrateMetadata) -> bool) {
+                            needs_dep: &dyn Fn(&CrateMetadata) -> bool) {
         // don't perform this validation if the session has errors, as one of
         // those errors may indicate a circular dependency which could cause
         // this to stack overflow.
diff --git a/src/librustc_metadata/cstore.rs b/src/librustc_metadata/cstore.rs
index 54857ce1b82..48cf0b982f2 100644
--- a/src/librustc_metadata/cstore.rs
+++ b/src/librustc_metadata/cstore.rs
@@ -1,109 +1,23 @@
 // The crate store - a central repo for information collected about external
 // crates and libraries
 
-use crate::rmeta;
-use rustc::dep_graph::DepNodeIndex;
-use rustc::hir::def_id::{CrateNum, DefIndex};
-use rustc::hir::map::definitions::DefPathTable;
-use rustc::middle::cstore::{CrateSource, DepKind, ExternCrate};
-use rustc::mir::interpret::AllocDecodingState;
+use crate::rmeta::CrateMetadata;
+
+use rustc_data_structures::sync::Lrc;
 use rustc_index::vec::IndexVec;
-use rustc::util::nodemap::FxHashMap;
-use rustc_data_structures::sync::{Lrc, Lock, MetadataRef, Once, AtomicCell};
-use rustc_data_structures::svh::Svh;
+use rustc::hir::def_id::CrateNum;
 use syntax::ast;
 use syntax::edition::Edition;
-use syntax_expand::base::SyntaxExtension;
 use syntax::expand::allocator::AllocatorKind;
-use syntax_pos;
-use proc_macro::bridge::client::ProcMacro;
+use syntax_expand::base::SyntaxExtension;
 
 pub use crate::rmeta::{provide, provide_extern};
 
-// A map from external crate numbers (as decoded from some crate file) to
-// local crate numbers (as generated during this session). Each external
-// crate may refer to types in other external crates, and each has their
-// own crate numbers.
-crate type CrateNumMap = IndexVec<CrateNum, CrateNum>;
-
-crate struct MetadataBlob(pub MetadataRef);
-
-/// Holds information about a syntax_pos::SourceFile imported from another crate.
-/// See `imported_source_files()` for more information.
-crate struct ImportedSourceFile {
-    /// This SourceFile's byte-offset within the source_map of its original crate
-    pub original_start_pos: syntax_pos::BytePos,
-    /// The end of this SourceFile within the source_map of its original crate
-    pub original_end_pos: syntax_pos::BytePos,
-    /// The imported SourceFile's representation within the local source_map
-    pub translated_source_file: Lrc<syntax_pos::SourceFile>,
-}
-
-crate struct CrateMetadata {
-    /// The primary crate data - binary metadata blob.
-    crate blob: MetadataBlob,
-
-    // --- Some data pre-decoded from the metadata blob, usually for performance ---
-
-    /// Properties of the whole crate.
-    /// NOTE(eddyb) we pass `'static` to a `'tcx` parameter because this
-    /// lifetime is only used behind `Lazy`, and therefore acts like an
-    /// universal (`for<'tcx>`), that is paired up with whichever `TyCtxt`
-    /// is being used to decode those values.
-    crate root: rmeta::CrateRoot<'static>,
-    /// For each definition in this crate, we encode a key. When the
-    /// crate is loaded, we read all the keys and put them in this
-    /// hashmap, which gives the reverse mapping. This allows us to
-    /// quickly retrace a `DefPath`, which is needed for incremental
-    /// compilation support.
-    crate def_path_table: DefPathTable,
-    /// Trait impl data.
-    /// FIXME: Used only from queries and can use query cache,
-    /// so pre-decoding can probably be avoided.
-    crate trait_impls: FxHashMap<(u32, DefIndex), rmeta::Lazy<[DefIndex]>>,
-    /// Proc macro descriptions for this crate, if it's a proc macro crate.
-    crate raw_proc_macros: Option<&'static [ProcMacro]>,
-    /// Source maps for code from the crate.
-    crate source_map_import_info: Once<Vec<ImportedSourceFile>>,
-    /// Used for decoding interpret::AllocIds in a cached & thread-safe manner.
-    crate alloc_decoding_state: AllocDecodingState,
-    /// The `DepNodeIndex` of the `DepNode` representing this upstream crate.
-    /// It is initialized on the first access in `get_crate_dep_node_index()`.
-    /// Do not access the value directly, as it might not have been initialized yet.
-    /// The field must always be initialized to `DepNodeIndex::INVALID`.
-    crate dep_node_index: AtomicCell<DepNodeIndex>,
-
-    // --- Other significant crate properties ---
-
-    /// ID of this crate, from the current compilation session's point of view.
-    crate cnum: CrateNum,
-    /// Maps crate IDs as they are were seen from this crate's compilation sessions into
-    /// IDs as they are seen from the current compilation session.
-    crate cnum_map: CrateNumMap,
-    /// Same ID set as `cnum_map` plus maybe some injected crates like panic runtime.
-    crate dependencies: Lock<Vec<CrateNum>>,
-    /// How to link (or not link) this crate to the currently compiled crate.
-    crate dep_kind: Lock<DepKind>,
-    /// Filesystem location of this crate.
-    crate source: CrateSource,
-    /// Whether or not this crate should be consider a private dependency
-    /// for purposes of the 'exported_private_dependencies' lint
-    crate private_dep: bool,
-    /// The hash for the host proc macro. Used to support `-Z dual-proc-macro`.
-    crate host_hash: Option<Svh>,
-
-    // --- Data used only for improving diagnostics ---
-
-    /// Information about the `extern crate` item or path that caused this crate to be loaded.
-    /// If this is `None`, then the crate was injected (e.g., by the allocator).
-    crate extern_crate: Lock<Option<ExternCrate>>,
-}
-
 #[derive(Clone)]
 pub struct CStore {
     metas: IndexVec<CrateNum, Option<Lrc<CrateMetadata>>>,
-    pub(crate) injected_panic_runtime: Option<CrateNum>,
-    pub(crate) allocator_kind: Option<AllocatorKind>,
+    crate injected_panic_runtime: Option<CrateNum>,
+    crate allocator_kind: Option<AllocatorKind>,
 }
 
 pub enum LoadedMacro {
diff --git a/src/librustc_metadata/locator.rs b/src/librustc_metadata/locator.rs
index 582602138e5..64230fd9e60 100644
--- a/src/librustc_metadata/locator.rs
+++ b/src/librustc_metadata/locator.rs
@@ -212,9 +212,8 @@
 //! no means all of the necessary details. Take a look at the rest of
 //! metadata::locator or metadata::creader for all the juicy details!
 
-use crate::cstore::MetadataBlob;
 use crate::creader::Library;
-use crate::rmeta::{METADATA_HEADER, rustc_version};
+use crate::rmeta::{METADATA_HEADER, rustc_version, MetadataBlob};
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::svh::Svh;
@@ -249,37 +248,47 @@ use log::{debug, info, warn};
 use rustc_error_codes::*;
 
 #[derive(Clone)]
-crate struct CrateMismatch {
+struct CrateMismatch {
     path: PathBuf,
     got: String,
 }
 
 #[derive(Clone)]
-crate struct Context<'a> {
-    pub sess: &'a Session,
-    pub span: Span,
-    pub crate_name: Symbol,
+crate struct CrateLocator<'a> {
+    // Immutable per-session configuration.
+    sess: &'a Session,
+    metadata_loader: &'a dyn MetadataLoader,
+
+    // Immutable per-search configuration.
+    crate_name: Symbol,
+    exact_paths: Vec<PathBuf>,
     pub hash: Option<&'a Svh>,
     pub host_hash: Option<&'a Svh>,
-    pub extra_filename: Option<&'a str>,
-    // points to either self.sess.target.target or self.sess.host, must match triple
+    extra_filename: Option<&'a str>,
     pub target: &'a Target,
     pub triple: TargetTriple,
     pub filesearch: FileSearch<'a>,
-    pub root: Option<&'a CratePaths>,
-    pub rejected_via_hash: Vec<CrateMismatch>,
-    pub rejected_via_triple: Vec<CrateMismatch>,
-    pub rejected_via_kind: Vec<CrateMismatch>,
-    pub rejected_via_version: Vec<CrateMismatch>,
-    pub rejected_via_filename: Vec<CrateMismatch>,
-    pub should_match_name: bool,
+    span: Span,
+    root: Option<&'a CratePaths>,
     pub is_proc_macro: Option<bool>,
-    pub metadata_loader: &'a dyn MetadataLoader,
+
+    // Mutable in-progress state or output.
+    rejected_via_hash: Vec<CrateMismatch>,
+    rejected_via_triple: Vec<CrateMismatch>,
+    rejected_via_kind: Vec<CrateMismatch>,
+    rejected_via_version: Vec<CrateMismatch>,
+    rejected_via_filename: Vec<CrateMismatch>,
 }
 
 crate struct CratePaths {
-    pub name: Symbol,
-    pub source: CrateSource,
+    name: Symbol,
+    source: CrateSource,
+}
+
+impl CratePaths {
+    crate fn new(name: Symbol, source: CrateSource) -> CratePaths {
+        CratePaths { name, source }
+    }
 }
 
 #[derive(Copy, Clone, PartialEq)]
@@ -299,7 +308,58 @@ impl fmt::Display for CrateFlavor {
     }
 }
 
-impl<'a> Context<'a> {
+impl<'a> CrateLocator<'a> {
+    crate fn new(
+        sess: &'a Session,
+        metadata_loader: &'a dyn MetadataLoader,
+        crate_name: Symbol,
+        hash: Option<&'a Svh>,
+        host_hash: Option<&'a Svh>,
+        extra_filename: Option<&'a str>,
+        is_host: bool,
+        path_kind: PathKind,
+        span: Span,
+        root: Option<&'a CratePaths>,
+        is_proc_macro: Option<bool>,
+    ) -> CrateLocator<'a> {
+        CrateLocator {
+            sess,
+            metadata_loader,
+            crate_name,
+            exact_paths: if hash.is_none() {
+                sess.opts.externs.get(&crate_name.as_str()).into_iter()
+                    .flat_map(|entry| entry.locations.iter())
+                    .filter_map(|location| location.clone().map(PathBuf::from)).collect()
+            } else {
+                // SVH being specified means this is a transitive dependency,
+                // so `--extern` options do not apply.
+                Vec::new()
+            },
+            hash,
+            host_hash,
+            extra_filename,
+            target: if is_host { &sess.host } else { &sess.target.target },
+            triple: if is_host {
+                TargetTriple::from_triple(config::host_triple())
+            } else {
+                sess.opts.target_triple.clone()
+            },
+            filesearch: if is_host {
+                sess.host_filesearch(path_kind)
+            } else {
+                sess.target_filesearch(path_kind)
+            },
+            span,
+            root,
+            is_proc_macro,
+            rejected_via_hash: Vec::new(),
+            rejected_via_triple: Vec::new(),
+            rejected_via_kind: Vec::new(),
+            rejected_via_version: Vec::new(),
+            rejected_via_filename: Vec::new(),
+        }
+    }
+
     crate fn reset(&mut self) {
         self.rejected_via_hash.clear();
         self.rejected_via_triple.clear();
@@ -309,6 +369,9 @@ impl<'a> Context<'a> {
     }
 
     crate fn maybe_load_library_crate(&mut self) -> Option<Library> {
+        if !self.exact_paths.is_empty() {
+            return self.find_commandline_library();
+        }
         let mut seen_paths = FxHashSet::default();
         match self.extra_filename {
             Some(s) => self.find_library_crate(s, &mut seen_paths)
@@ -434,21 +497,6 @@ impl<'a> Context<'a> {
                           extra_prefix: &str,
                           seen_paths: &mut FxHashSet<PathBuf>)
                           -> Option<Library> {
-        // If an SVH is specified, then this is a transitive dependency that
-        // must be loaded via -L plus some filtering.
-        if self.hash.is_none() {
-            self.should_match_name = false;
-            if let Some(entry) = self.sess.opts.externs.get(&self.crate_name.as_str()) {
-                // Only use `--extern crate_name=path` here, not `--extern crate_name`.
-                if entry.locations.iter().any(|l| l.is_some()) {
-                    return self.find_commandline_library(
-                        entry.locations.iter().filter_map(|l| l.as_ref()),
-                    );
-                }
-            }
-            self.should_match_name = true;
-        }
-
         let dypair = self.dylibname();
         let staticpair = self.staticlibname();
 
@@ -716,15 +764,16 @@ impl<'a> Context<'a> {
         }
 
         let root = metadata.get_root();
-        if let Some(is_proc_macro) = self.is_proc_macro {
-            if root.proc_macro_data.is_some() != is_proc_macro {
+        if let Some(expected_is_proc_macro) = self.is_proc_macro {
+            let is_proc_macro = root.is_proc_macro_crate();
+            if is_proc_macro != expected_is_proc_macro {
                 info!("Rejecting via proc macro: expected {} got {}",
-                      is_proc_macro, root.proc_macro_data.is_some());
+                      expected_is_proc_macro, is_proc_macro);
                 return None;
             }
         }
 
-        if self.should_match_name {
+        if self.exact_paths.is_empty() {
             if self.crate_name != root.name {
                 info!("Rejecting via crate name");
                 return None;
@@ -771,9 +820,7 @@ impl<'a> Context<'a> {
         (t.options.staticlib_prefix.clone(), t.options.staticlib_suffix.clone())
     }
 
-    fn find_commandline_library<'b, LOCS>(&mut self, locs: LOCS) -> Option<Library>
-        where LOCS: Iterator<Item = &'b String>
-    {
+    fn find_commandline_library(&mut self) -> Option<Library> {
         // First, filter out all libraries that look suspicious. We only accept
         // files which actually exist that have the correct naming scheme for
         // rlibs/dylibs.
@@ -783,10 +830,12 @@ impl<'a> Context<'a> {
         let mut rmetas = FxHashMap::default();
         let mut dylibs = FxHashMap::default();
         {
-            let locs = locs.map(|l| PathBuf::from(l)).filter(|loc| {
+                let crate_name = self.crate_name;
+                let rejected_via_filename = &mut self.rejected_via_filename;
+                let locs = self.exact_paths.iter().filter(|loc| {
                 if !loc.exists() {
                     sess.err(&format!("extern location for {} does not exist: {}",
-                                      self.crate_name,
+                                      crate_name,
                                       loc.display()));
                     return false;
                 }
@@ -794,7 +843,7 @@ impl<'a> Context<'a> {
                     Some(file) => file,
                     None => {
                         sess.err(&format!("extern location for {} is not a file: {}",
-                                          self.crate_name,
+                                          crate_name,
                                           loc.display()));
                         return false;
                     }
@@ -809,8 +858,8 @@ impl<'a> Context<'a> {
                     }
                 }
 
-                self.rejected_via_filename.push(CrateMismatch {
-                    path: loc.clone(),
+                rejected_via_filename.push(CrateMismatch {
+                    path: (*loc).clone(),
                     got: String::new(),
                 });
 
@@ -907,7 +956,7 @@ fn get_metadata_section_imp(target: &Target,
             rustc_erase_owner!(OwningRef::new(StableDerefMmap(mmap)).map_owner_box())
         }
     };
-    let blob = MetadataBlob(raw_bytes);
+    let blob = MetadataBlob::new(raw_bytes);
     if blob.is_compatible() {
         Ok(blob)
     } else {
@@ -927,28 +976,21 @@ pub fn find_plugin_registrar(
     let host_triple = TargetTriple::from_triple(config::host_triple());
     let is_cross = target_triple != host_triple;
     let mut target_only = false;
-    let mut locate_ctxt = Context {
+    let mut locator = CrateLocator::new(
         sess,
-        span,
-        crate_name: name,
-        hash: None,
-        host_hash: None,
-        extra_filename: None,
-        filesearch: sess.host_filesearch(PathKind::Crate),
-        target: &sess.host,
-        triple: host_triple,
-        root: None,
-        rejected_via_hash: vec![],
-        rejected_via_triple: vec![],
-        rejected_via_kind: vec![],
-        rejected_via_version: vec![],
-        rejected_via_filename: vec![],
-        should_match_name: true,
-        is_proc_macro: None,
         metadata_loader,
-    };
+        name,
+        None, // hash
+        None, // host_hash
+        None, // extra_filename
+        true, // is_host
+        PathKind::Crate,
+        span,
+        None, // root
+        None, // is_proc_macro
+    );
 
-    let library = locate_ctxt.maybe_load_library_crate().or_else(|| {
+    let library = locator.maybe_load_library_crate().or_else(|| {
         if !is_cross {
             return None
         }
@@ -956,15 +998,15 @@ pub fn find_plugin_registrar(
         // try to load a plugin registrar function,
         target_only = true;
 
-        locate_ctxt.target = &sess.target.target;
-        locate_ctxt.triple = target_triple;
-        locate_ctxt.filesearch = sess.target_filesearch(PathKind::Crate);
+        locator.target = &sess.target.target;
+        locator.triple = target_triple;
+        locator.filesearch = sess.target_filesearch(PathKind::Crate);
 
-        locate_ctxt.maybe_load_library_crate()
+        locator.maybe_load_library_crate()
     });
     let library = match library {
         Some(l) => l,
-        None => locate_ctxt.report_errs(),
+        None => locator.report_errs(),
     };
 
     if target_only {
diff --git a/src/librustc_metadata/rmeta/decoder.rs b/src/librustc_metadata/rmeta/decoder.rs
index fc0a0010240..7b0cf451ff9 100644
--- a/src/librustc_metadata/rmeta/decoder.rs
+++ b/src/librustc_metadata/rmeta/decoder.rs
@@ -1,27 +1,30 @@
 // Decoding metadata from a single crate's metadata
 
-use crate::cstore::{self, CrateMetadata, MetadataBlob};
 use crate::rmeta::*;
 use crate::rmeta::table::{FixedSizeEncoding, PerDefTable};
 
 use rustc_index::vec::IndexVec;
-use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::sync::{Lrc, Lock, Once, AtomicCell};
 use rustc::hir::map::{DefKey, DefPath, DefPathData, DefPathHash};
+use rustc::hir::map::definitions::DefPathTable;
 use rustc::hir;
+use rustc::middle::cstore::{CrateSource, ExternCrate};
 use rustc::middle::cstore::{LinkagePreference, NativeLibrary, ForeignModule};
 use rustc::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use rustc::hir::def::{self, Res, DefKind, CtorOf, CtorKind};
 use rustc::hir::def_id::{CrateNum, DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
-use rustc::dep_graph::{DepNodeIndex, DepKind};
+use rustc_data_structures::svh::Svh;
+use rustc::dep_graph::{self, DepNodeIndex};
 use rustc::middle::lang_items;
 use rustc::mir::{self, interpret};
-use rustc::mir::interpret::AllocDecodingSession;
+use rustc::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc::session::Session;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::ty::codec::TyDecoder;
 use rustc::mir::{Body, Promoted};
+use rustc::util::common::record_time;
 use rustc::util::captures::Captures;
 
 use std::io;
@@ -44,7 +47,86 @@ pub use cstore_impl::{provide, provide_extern};
 
 mod cstore_impl;
 
-crate struct DecodeContext<'a, 'tcx> {
+crate struct MetadataBlob(MetadataRef);
+
+// A map from external crate numbers (as decoded from some crate file) to
+// local crate numbers (as generated during this session). Each external
+// crate may refer to types in other external crates, and each has their
+// own crate numbers.
+crate type CrateNumMap = IndexVec<CrateNum, CrateNum>;
+
+crate struct CrateMetadata {
+    /// The primary crate data - binary metadata blob.
+    blob: MetadataBlob,
+
+    // --- Some data pre-decoded from the metadata blob, usually for performance ---
+
+    /// Properties of the whole crate.
+    /// NOTE(eddyb) we pass `'static` to a `'tcx` parameter because this
+    /// lifetime is only used behind `Lazy`, and therefore acts like an
+    /// universal (`for<'tcx>`), that is paired up with whichever `TyCtxt`
+    /// is being used to decode those values.
+    crate root: CrateRoot<'static>,
+    /// For each definition in this crate, we encode a key. When the
+    /// crate is loaded, we read all the keys and put them in this
+    /// hashmap, which gives the reverse mapping. This allows us to
+    /// quickly retrace a `DefPath`, which is needed for incremental
+    /// compilation support.
+    def_path_table: DefPathTable,
+    /// Trait impl data.
+    /// FIXME: Used only from queries and can use query cache,
+    /// so pre-decoding can probably be avoided.
+    trait_impls: FxHashMap<(u32, DefIndex), Lazy<[DefIndex]>>,
+    /// Proc macro descriptions for this crate, if it's a proc macro crate.
+    raw_proc_macros: Option<&'static [ProcMacro]>,
+    /// Source maps for code from the crate.
+    source_map_import_info: Once<Vec<ImportedSourceFile>>,
+    /// Used for decoding interpret::AllocIds in a cached & thread-safe manner.
+    alloc_decoding_state: AllocDecodingState,
+    /// The `DepNodeIndex` of the `DepNode` representing this upstream crate.
+    /// It is initialized on the first access in `get_crate_dep_node_index()`.
+    /// Do not access the value directly, as it might not have been initialized yet.
+    /// The field must always be initialized to `DepNodeIndex::INVALID`.
+    dep_node_index: AtomicCell<DepNodeIndex>,
+
+    // --- Other significant crate properties ---
+
+    /// ID of this crate, from the current compilation session's point of view.
+    cnum: CrateNum,
+    /// Maps crate IDs as they are were seen from this crate's compilation sessions into
+    /// IDs as they are seen from the current compilation session.
+    cnum_map: CrateNumMap,
+    /// Same ID set as `cnum_map` plus maybe some injected crates like panic runtime.
+    crate dependencies: Lock<Vec<CrateNum>>,
+    /// How to link (or not link) this crate to the currently compiled crate.
+    crate dep_kind: Lock<DepKind>,
+    /// Filesystem location of this crate.
+    crate source: CrateSource,
+    /// Whether or not this crate should be consider a private dependency
+    /// for purposes of the 'exported_private_dependencies' lint
+    private_dep: bool,
+    /// The hash for the host proc macro. Used to support `-Z dual-proc-macro`.
+    host_hash: Option<Svh>,
+
+    // --- Data used only for improving diagnostics ---
+
+    /// Information about the `extern crate` item or path that caused this crate to be loaded.
+    /// If this is `None`, then the crate was injected (e.g., by the allocator).
+    crate extern_crate: Lock<Option<ExternCrate>>,
+}
+
+/// Holds information about a syntax_pos::SourceFile imported from another crate.
+/// See `imported_source_files()` for more information.
+struct ImportedSourceFile {
+    /// This SourceFile's byte-offset within the source_map of its original crate
+    original_start_pos: syntax_pos::BytePos,
+    /// The end of this SourceFile within the source_map of its original crate
+    original_end_pos: syntax_pos::BytePos,
+    /// The imported SourceFile's representation within the local source_map
+    translated_source_file: Lrc<syntax_pos::SourceFile>,
+}
+
+pub(super) struct DecodeContext<'a, 'tcx> {
     opaque: opaque::Decoder<'a>,
     cdata: Option<&'a CrateMetadata>,
     sess: Option<&'tcx Session>,
@@ -60,7 +142,7 @@ crate struct DecodeContext<'a, 'tcx> {
 }
 
 /// Abstract over the various ways one can create metadata decoders.
-crate trait Metadata<'a, 'tcx>: Copy {
+pub(super) trait Metadata<'a, 'tcx>: Copy {
     fn raw_bytes(self) -> &'a [u8];
     fn cdata(self) -> Option<&'a CrateMetadata> { None }
     fn sess(self) -> Option<&'tcx Session> { None }
@@ -136,7 +218,7 @@ impl<'a, 'tcx> Metadata<'a, 'tcx> for (&'a CrateMetadata, TyCtxt<'tcx>) {
 }
 
 impl<'a, 'tcx, T: Encodable + Decodable> Lazy<T> {
-    crate fn decode<M: Metadata<'a, 'tcx>>(self, metadata: M) -> T {
+    fn decode<M: Metadata<'a, 'tcx>>(self, metadata: M) -> T {
         let mut dcx = metadata.decoder(self.position.get());
         dcx.lazy_state = LazyState::NodeStart(self.position);
         T::decode(&mut dcx).unwrap()
@@ -144,7 +226,7 @@ impl<'a, 'tcx, T: Encodable + Decodable> Lazy<T> {
 }
 
 impl<'a: 'x, 'tcx: 'x, 'x, T: Encodable + Decodable> Lazy<[T]> {
-    crate fn decode<M: Metadata<'a, 'tcx>>(
+    fn decode<M: Metadata<'a, 'tcx>>(
         self,
         metadata: M,
     ) -> impl ExactSizeIterator<Item = T> + Captures<'a> + Captures<'tcx> + 'x {
@@ -393,7 +475,11 @@ for DecodeContext<'a, 'tcx> {
 
 implement_ty_decoder!( DecodeContext<'a, 'tcx> );
 
-impl<'tcx> MetadataBlob {
+impl MetadataBlob {
+    crate fn new(metadata_ref: MetadataRef) -> MetadataBlob {
+        MetadataBlob(metadata_ref)
+    }
+
     crate fn is_compatible(&self) -> bool {
         self.raw_bytes().starts_with(METADATA_HEADER)
     }
@@ -467,14 +553,62 @@ impl<'tcx> EntryKind<'tcx> {
     }
 }
 
+impl CrateRoot<'_> {
+    crate fn is_proc_macro_crate(&self) -> bool {
+        self.proc_macro_data.is_some()
+    }
+
+    crate fn decode_crate_deps(
+        &self,
+        metadata: &'a MetadataBlob,
+    ) -> impl ExactSizeIterator<Item = CrateDep> + Captures<'a> {
+        self.crate_deps.decode(metadata)
+    }
+}
+
 impl<'a, 'tcx> CrateMetadata {
-    fn is_proc_macro_crate(&self) -> bool {
-        self.root.proc_macro_decls_static.is_some()
+    crate fn new(
+        sess: &Session,
+        blob: MetadataBlob,
+        root: CrateRoot<'static>,
+        raw_proc_macros: Option<&'static [ProcMacro]>,
+        cnum: CrateNum,
+        cnum_map: CrateNumMap,
+        dep_kind: DepKind,
+        source: CrateSource,
+        private_dep: bool,
+        host_hash: Option<Svh>,
+    ) -> CrateMetadata {
+        let def_path_table = record_time(&sess.perf_stats.decode_def_path_tables_time, || {
+            root.def_path_table.decode((&blob, sess))
+        });
+        let trait_impls = root.impls.decode((&blob, sess))
+            .map(|trait_impls| (trait_impls.trait_id, trait_impls.impls)).collect();
+        let alloc_decoding_state =
+            AllocDecodingState::new(root.interpret_alloc_index.decode(&blob).collect());
+        let dependencies = Lock::new(cnum_map.iter().cloned().collect());
+        CrateMetadata {
+            blob,
+            root,
+            def_path_table,
+            trait_impls,
+            raw_proc_macros,
+            source_map_import_info: Once::new(),
+            alloc_decoding_state,
+            dep_node_index: AtomicCell::new(DepNodeIndex::INVALID),
+            cnum,
+            cnum_map,
+            dependencies,
+            dep_kind: Lock::new(dep_kind),
+            source,
+            private_dep,
+            host_hash,
+            extern_crate: Lock::new(None),
+        }
     }
 
     fn is_proc_macro(&self, id: DefIndex) -> bool {
-        self.is_proc_macro_crate() &&
-            self.root.proc_macro_data.unwrap().decode(self).find(|x| *x == id).is_some()
+        self.root.proc_macro_data.and_then(|data| data.decode(self).find(|x| *x == id)).is_some()
     }
 
     fn maybe_kind(&self, item_id: DefIndex) -> Option<EntryKind<'tcx>> {
@@ -757,7 +891,7 @@ impl<'a, 'tcx> CrateMetadata {
 
     /// Iterates over the language items in the given crate.
     fn get_lang_items(&self, tcx: TyCtxt<'tcx>) -> &'tcx [(DefId, usize)] {
-        if self.is_proc_macro_crate() {
+        if self.root.is_proc_macro_crate() {
             // Proc macro crates do not export any lang-items to the target.
             &[]
         } else {
@@ -773,7 +907,7 @@ impl<'a, 'tcx> CrateMetadata {
         &self,
         tcx: TyCtxt<'tcx>,
     ) -> &'tcx FxHashMap<Symbol, DefId> {
-        tcx.arena.alloc(if self.is_proc_macro_crate() {
+        tcx.arena.alloc(if self.root.is_proc_macro_crate() {
             // Proc macro crates do not export any diagnostic-items to the target.
             Default::default()
         } else {
@@ -1081,7 +1215,7 @@ impl<'a, 'tcx> CrateMetadata {
         tcx: TyCtxt<'tcx>,
         filter: Option<DefId>,
     ) -> &'tcx [DefId] {
-        if self.is_proc_macro_crate() {
+        if self.root.is_proc_macro_crate() {
             // proc-macro crates export no trait impls.
             return &[]
         }
@@ -1125,7 +1259,7 @@ impl<'a, 'tcx> CrateMetadata {
 
 
     fn get_native_libraries(&self, sess: &Session) -> Vec<NativeLibrary> {
-        if self.is_proc_macro_crate() {
+        if self.root.is_proc_macro_crate() {
             // Proc macro crates do not have any *target* native libraries.
             vec![]
         } else {
@@ -1134,7 +1268,7 @@ impl<'a, 'tcx> CrateMetadata {
     }
 
     fn get_foreign_modules(&self, tcx: TyCtxt<'tcx>) -> &'tcx [ForeignModule] {
-        if self.is_proc_macro_crate() {
+        if self.root.is_proc_macro_crate() {
             // Proc macro crates do not have any *target* foreign modules.
             &[]
         } else {
@@ -1157,7 +1291,7 @@ impl<'a, 'tcx> CrateMetadata {
     }
 
     fn get_missing_lang_items(&self, tcx: TyCtxt<'tcx>) -> &'tcx [lang_items::LangItem] {
-        if self.is_proc_macro_crate() {
+        if self.root.is_proc_macro_crate() {
             // Proc macro crates do not depend on any target weak lang-items.
             &[]
         } else {
@@ -1181,7 +1315,7 @@ impl<'a, 'tcx> CrateMetadata {
         &self,
         tcx: TyCtxt<'tcx>,
     ) -> Vec<(ExportedSymbol<'tcx>, SymbolExportLevel)> {
-        if self.is_proc_macro_crate() {
+        if self.root.is_proc_macro_crate() {
             // If this crate is a custom derive crate, then we're not even going to
             // link those in so we skip those crates.
             vec![]
@@ -1296,7 +1430,7 @@ impl<'a, 'tcx> CrateMetadata {
     fn imported_source_files(
         &'a self,
         local_source_map: &source_map::SourceMap,
-    ) -> &[cstore::ImportedSourceFile] {
+    ) -> &[ImportedSourceFile] {
         self.source_map_import_info.init_locking(|| {
             let external_source_map = self.root.source_map.decode(self);
 
@@ -1351,7 +1485,7 @@ impl<'a, 'tcx> CrateMetadata {
                        local_version.name, start_pos, end_pos,
                        local_version.start_pos, local_version.end_pos);
 
-                cstore::ImportedSourceFile {
+                ImportedSourceFile {
                     original_start_pos: start_pos,
                     original_end_pos: end_pos,
                     translated_source_file: local_version,
@@ -1374,7 +1508,7 @@ impl<'a, 'tcx> CrateMetadata {
             // would always write the same value.
 
             let def_path_hash = self.def_path_hash(CRATE_DEF_INDEX);
-            let dep_node = def_path_hash.to_dep_node(DepKind::CrateMetadata);
+            let dep_node = def_path_hash.to_dep_node(dep_graph::DepKind::CrateMetadata);
 
             dep_node_index = tcx.dep_graph.dep_node_index_of(&dep_node);
             assert!(dep_node_index != DepNodeIndex::INVALID);
diff --git a/src/librustc_metadata/rmeta/decoder/cstore_impl.rs b/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
index a6cb3864ca7..abb0ceb4ff4 100644
--- a/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
+++ b/src/librustc_metadata/rmeta/decoder/cstore_impl.rs
@@ -52,7 +52,7 @@ macro_rules! provide {
                 assert!(!$def_id.is_local());
 
                 let $cdata = $tcx.crate_data_as_any($def_id.krate);
-                let $cdata = $cdata.downcast_ref::<cstore::CrateMetadata>()
+                let $cdata = $cdata.downcast_ref::<rmeta::CrateMetadata>()
                     .expect("CrateStore created data is not a CrateMetadata");
 
                 if $tcx.dep_graph.is_fully_enabled() {
@@ -410,7 +410,7 @@ impl cstore::CStore {
         let _prof_timer = sess.prof.generic_activity("metadata_load_macro");
 
         let data = self.get_crate_data(id.krate);
-        if data.is_proc_macro_crate() {
+        if data.root.is_proc_macro_crate() {
             return LoadedMacro::ProcMacro(data.load_proc_macro(id.index, sess));
         }
 
diff --git a/src/librustc_metadata/rmeta/mod.rs b/src/librustc_metadata/rmeta/mod.rs
index 850ee5afbc8..23c0204ee25 100644
--- a/src/librustc_metadata/rmeta/mod.rs
+++ b/src/librustc_metadata/rmeta/mod.rs
@@ -14,6 +14,7 @@ use rustc::ty::{self, Ty, ReprOptions};
 use rustc_target::spec::{PanicStrategy, TargetTriple};
 use rustc_index::vec::IndexVec;
 use rustc_data_structures::svh::Svh;
+use rustc_data_structures::sync::MetadataRef;
 use rustc_serialize::Encodable;
 use syntax::{ast, attr};
 use syntax::edition::Edition;
@@ -24,6 +25,7 @@ use std::marker::PhantomData;
 use std::num::NonZeroUsize;
 
 pub use decoder::{provide, provide_extern};
+crate use decoder::{CrateMetadata, CrateNumMap, MetadataBlob};
 
 mod decoder;
 mod encoder;
@@ -49,7 +51,7 @@ crate const METADATA_HEADER: &[u8; 8] =
 
 /// Additional metadata for a `Lazy<T>` where `T` may not be `Sized`,
 /// e.g. for `Lazy<[T]>`, this is the length (count of `T` values).
-crate trait LazyMeta {
+trait LazyMeta {
     type Meta: Copy + 'static;
 
     /// Returns the minimum encoded size.
@@ -103,7 +105,7 @@ impl<T: Encodable> LazyMeta for [T] {
 #[must_use]
 // FIXME(#59875) the `Meta` parameter only exists to dodge
 // invariance wrt `T` (coming from the `meta: T::Meta` field).
-crate struct Lazy<T, Meta = <T as LazyMeta>::Meta>
+struct Lazy<T, Meta = <T as LazyMeta>::Meta>
     where T: ?Sized + LazyMeta<Meta = Meta>,
           Meta: 'static + Copy,
 {
@@ -186,7 +188,7 @@ crate struct CrateRoot<'tcx> {
     proc_macro_decls_static: Option<DefIndex>,
     proc_macro_stability: Option<attr::Stability>,
 
-    pub crate_deps: Lazy<[CrateDep]>,
+    crate_deps: Lazy<[CrateDep]>,
     dylib_dependency_formats: Lazy<[Option<LinkagePreference>]>,
     lib_features: Lazy<[(Symbol, Option<Symbol>)]>,
     lang_items: Lazy<[(DefIndex, usize)]>,
@@ -195,16 +197,15 @@ crate struct CrateRoot<'tcx> {
     native_libraries: Lazy<[NativeLibrary]>,
     foreign_modules: Lazy<[ForeignModule]>,
     source_map: Lazy<[syntax_pos::SourceFile]>,
-    pub def_path_table: Lazy<hir::map::definitions::DefPathTable>,
-    pub impls: Lazy<[TraitImpls]>,
+    def_path_table: Lazy<hir::map::definitions::DefPathTable>,
+    impls: Lazy<[TraitImpls]>,
     exported_symbols: Lazy!([(ExportedSymbol<'tcx>, SymbolExportLevel)]),
-    pub interpret_alloc_index: Lazy<[u32]>,
+    interpret_alloc_index: Lazy<[u32]>,
 
     per_def: LazyPerDefTables<'tcx>,
 
-    /// The DefIndex's of any proc macros delcared by
-    /// this crate
-    pub proc_macro_data: Option<Lazy<[DefIndex]>>,
+    /// The DefIndex's of any proc macros delcared by this crate.
+    proc_macro_data: Option<Lazy<[DefIndex]>>,
 
     compiler_builtins: bool,
     pub needs_allocator: bool,
@@ -227,8 +228,8 @@ crate struct CrateDep {
 
 #[derive(RustcEncodable, RustcDecodable)]
 crate struct TraitImpls {
-    pub trait_id: (u32, DefIndex),
-    pub impls: Lazy<[DefIndex]>,
+    trait_id: (u32, DefIndex),
+    impls: Lazy<[DefIndex]>,
 }
 
 #[derive(RustcEncodable, RustcDecodable)]