rustc_metadata: Remove resolutions for extern crate items from CStore

Use a more traditional scheme with providing them as a resolver output

src/librustc/middle/cstore.rs

@@ -214,7 +214,6 @@ pub trait CrateStore {
     fn crate_is_private_dep_untracked(&self, cnum: CrateNum) -> bool;
     fn crate_disambiguator_untracked(&self, cnum: CrateNum) -> CrateDisambiguator;
     fn crate_hash_untracked(&self, cnum: CrateNum) -> Svh;
-    fn extern_mod_stmt_cnum_untracked(&self, emod_id: ast::NodeId) -> Option<CrateNum>;
     fn item_generics_cloned_untracked(&self, def: DefId, sess: &Session) -> ty::Generics;
     fn postorder_cnums_untracked(&self) -> Vec<CrateNum>;
 

src/librustc/ty/context.rs

@@ -43,7 +43,7 @@ use crate::ty::subst::{UserSubsts, GenericArgKind};
 use crate::ty::{BoundVar, BindingMode};
 use crate::ty::CanonicalPolyFnSig;
 use crate::util::common::ErrorReported;
-use crate::util::nodemap::{DefIdMap, DefIdSet, ItemLocalMap, ItemLocalSet};
+use crate::util::nodemap::{DefIdMap, DefIdSet, ItemLocalMap, ItemLocalSet, NodeMap};
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 use crate::util::profiling::SelfProfilerRef;
 
@@ -1051,6 +1051,9 @@ pub struct GlobalCtxt<'tcx> {
     /// Common consts, pre-interned for your convenience.
     pub consts: CommonConsts<'tcx>,
 
+    /// Resolutions of `extern crate` items produced by resolver.
+    extern_crate_map: NodeMap<CrateNum>,
+
     /// Map indicating what traits are in scope for places where this
     /// is relevant; generated by resolve.
     trait_map: FxHashMap<DefIndex,
@@ -1274,6 +1277,7 @@ impl<'tcx> TyCtxt<'tcx> {
             types: common_types,
             lifetimes: common_lifetimes,
             consts: common_consts,
+            extern_crate_map: resolutions.extern_crate_map,
             trait_map,
             export_map: resolutions.export_map.into_iter().map(|(k, v)| {
                 let exports: Vec<_> = v.into_iter().map(|e| {
@@ -2951,7 +2955,7 @@ pub fn provide(providers: &mut ty::query::Providers<'_>) {
     };
     providers.extern_mod_stmt_cnum = |tcx, id| {
         let id = tcx.hir().as_local_node_id(id).unwrap();
-        tcx.cstore.extern_mod_stmt_cnum_untracked(id)
+        tcx.extern_crate_map.get(&id).cloned()
     };
     providers.all_crate_nums = |tcx, cnum| {
         assert_eq!(cnum, LOCAL_CRATE);

src/librustc/ty/mod.rs

@@ -28,7 +28,7 @@ use crate::ty::subst::{Subst, InternalSubsts, SubstsRef};
 use crate::ty::util::{IntTypeExt, Discr};
 use crate::ty::walk::TypeWalker;
 use crate::util::captures::Captures;
-use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
+use crate::util::nodemap::{NodeMap, NodeSet, DefIdMap, FxHashMap};
 use arena::SyncDroplessArena;
 use crate::session::DataTypeKind;
 
@@ -121,6 +121,7 @@ mod sty;
 
 #[derive(Clone)]
 pub struct Resolutions {
+    pub extern_crate_map: NodeMap<CrateNum>,
     pub trait_map: TraitMap,
     pub maybe_unused_trait_imports: NodeSet,
     pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,

src/librustc_interface/passes.rs

@@ -169,6 +169,7 @@ impl ExpansionResult {
         ExpansionResult {
             defs: Steal::new(resolver.definitions),
             resolutions: Steal::new(Resolutions {
+                extern_crate_map: resolver.extern_crate_map,
                 export_map: resolver.export_map,
                 trait_map: resolver.trait_map,
                 glob_map: resolver.glob_map,
@@ -187,6 +188,7 @@ impl ExpansionResult {
         ExpansionResult {
             defs: Steal::new(resolver.definitions.clone()),
             resolutions: Steal::new(Resolutions {
+                extern_crate_map: resolver.extern_crate_map.clone(),
                 export_map: resolver.export_map.clone(),
                 trait_map: resolver.trait_map.clone(),
                 glob_map: resolver.glob_map.clone(),

src/librustc_metadata/creader.rs

@@ -1004,7 +1004,6 @@ impl<'a> CrateLoader<'a> {
                     },
                     &mut FxHashSet::default(),
                 );
-                self.cstore.add_extern_mod_stmt_cnum(item.id, cnum);
                 cnum
             }
             _ => bug!(),

src/librustc_metadata/cstore.rs

@@ -8,7 +8,7 @@ use rustc::hir::map::definitions::DefPathTable;
 use rustc::middle::cstore::{CrateSource, DepKind, ExternCrate, MetadataLoader};
 use rustc::mir::interpret::AllocDecodingState;
 use rustc_index::vec::IndexVec;
-use rustc::util::nodemap::{FxHashMap, NodeMap};
+use rustc::util::nodemap::FxHashMap;
 use rustc_data_structures::sync::{Lrc, RwLock, Lock, MetadataRef, AtomicCell};
 use syntax::ast;
 use syntax::ext::base::SyntaxExtension;
@@ -96,8 +96,6 @@ pub struct CrateMetadata {
 
 pub struct CStore {
     metas: RwLock<IndexVec<CrateNum, Option<Lrc<CrateMetadata>>>>,
-    /// Map from NodeId's of local extern crate statements to crate numbers
-    extern_mod_crate_map: Lock<NodeMap<CrateNum>>,
     crate metadata_loader: Box<dyn MetadataLoader + Sync>,
 }
 
@@ -114,7 +112,6 @@ impl CStore {
             // corresponding `CrateNum`. This first entry will always remain
             // `None`.
             metas: RwLock::new(IndexVec::from_elem_n(None, 1)),
-            extern_mod_crate_map: Default::default(),
             metadata_loader,
         }
     }
@@ -178,12 +175,4 @@ impl CStore {
         }
         return ordering
     }
-
-    crate fn add_extern_mod_stmt_cnum(&self, emod_id: ast::NodeId, cnum: CrateNum) {
-        self.extern_mod_crate_map.borrow_mut().insert(emod_id, cnum);
-    }
-
-    crate fn do_extern_mod_stmt_cnum(&self, emod_id: ast::NodeId) -> Option<CrateNum> {
-        self.extern_mod_crate_map.borrow().get(&emod_id).cloned()
-    }
 }

src/librustc_metadata/cstore_impl.rs

@@ -538,11 +538,6 @@ impl CrateStore for cstore::CStore {
         result
     }
 
-    fn extern_mod_stmt_cnum_untracked(&self, emod_id: ast::NodeId) -> Option<CrateNum>
-    {
-        self.do_extern_mod_stmt_cnum(emod_id)
-    }
-
     fn postorder_cnums_untracked(&self) -> Vec<CrateNum> {
         self.do_postorder_cnums_untracked()
     }

src/librustc_resolve/build_reduced_graph.rs

@@ -617,6 +617,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     let crate_id = self.r.crate_loader.process_extern_crate(
                         item, &self.r.definitions
                     );
+                    self.r.extern_crate_map.insert(item.id, crate_id);
                     self.r.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX })
                 };
 

src/librustc_resolve/lib.rs

@@ -26,7 +26,7 @@ use rustc::session::Session;
 use rustc::lint;
 use rustc::hir::def::{self, DefKind, PartialRes, CtorKind, CtorOf, NonMacroAttrKind, ExportMap};
 use rustc::hir::def::Namespace::*;
-use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
+use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, CrateNum, DefId};
 use rustc::hir::{TraitMap, GlobMap};
 use rustc::ty::{self, DefIdTree};
 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
@@ -855,6 +855,8 @@ pub struct Resolver<'a> {
     /// Resolutions for labels (node IDs of their corresponding blocks or loops).
     label_res_map: NodeMap<NodeId>,
 
+    /// `CrateNum` resolutions of `extern crate` items.
+    pub extern_crate_map: NodeMap<CrateNum>,
     pub export_map: ExportMap<NodeId>,
     pub trait_map: TraitMap,
 
@@ -1155,6 +1157,7 @@ impl<'a> Resolver<'a> {
             partial_res_map: Default::default(),
             import_res_map: Default::default(),
             label_res_map: Default::default(),
+            extern_crate_map: Default::default(),
             export_map: FxHashMap::default(),
             trait_map: Default::default(),
             empty_module,