rustc: Make the export_map of TyCtxt private

This map, like `trait_map`, is calculated in resolve, but we want to be sure to
track it for incremental compliation. Hide it behind a query to get more
refactorings later.

Author: alexcrichton

Diff for: src/librustc/dep_graph/dep_node.rs

@@ -529,6 +529,7 @@ define_dep_nodes!( <'tcx>
     [] ExternCrate(DefId),
     [] LintLevels,
     [] InScopeTraits(HirId),
+    [] ModuleExports(HirId),
 );
 
 trait DepNodeParams<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> : fmt::Debug {

Diff for: src/librustc/ty/context.rs

@@ -15,7 +15,7 @@ use errors::DiagnosticBuilder;
 use session::Session;
 use middle;
 use hir::{TraitCandidate, HirId};
-use hir::def::{Def, ExportMap};
+use hir::def::{Def, Export};
 use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use hir::map as hir_map;
 use hir::map::DefPathHash;
@@ -822,7 +822,7 @@ pub struct GlobalCtxt<'tcx> {
     trait_map: FxHashMap<HirId, Rc<Vec<TraitCandidate>>>,
 
     /// Export map produced by name resolution.
-    pub export_map: ExportMap,
+    export_map: FxHashMap<HirId, Rc<Vec<Export>>>,
 
     pub named_region_map: resolve_lifetime::NamedRegionMap,
 
@@ -1081,7 +1081,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             trait_map: resolutions.trait_map.into_iter().map(|(k, v)| {
                 (hir.node_to_hir_id(k), Rc::new(v))
             }).collect(),
-            export_map: resolutions.export_map,
+            export_map: resolutions.export_map.into_iter().map(|(k, v)| {
+                (hir.node_to_hir_id(k), Rc::new(v))
+            }).collect(),
             hir,
             def_path_hash_to_def_id,
             maps: maps::Maps::new(providers),
@@ -2006,6 +2008,13 @@ fn in_scope_traits<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: HirId)
     tcx.gcx.trait_map.get(&id).cloned()
 }
 
+fn module_exports<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: HirId)
+    -> Option<Rc<Vec<Export>>>
+{
+    tcx.gcx.export_map.get(&id).cloned()
+}
+
 pub fn provide(providers: &mut ty::maps::Providers) {
     providers.in_scope_traits = in_scope_traits;
+    providers.module_exports = module_exports;
 }

Diff for: src/librustc/ty/maps.rs

@@ -11,7 +11,7 @@
 use dep_graph::{DepConstructor, DepNode, DepNodeIndex};
 use errors::{Diagnostic, DiagnosticBuilder};
 use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
-use hir::def::Def;
+use hir::def::{Def, Export};
 use hir::{self, TraitCandidate, HirId};
 use lint;
 use middle::const_val;
@@ -555,6 +555,12 @@ impl<'tcx> QueryDescription for queries::in_scope_traits<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription for queries::module_exports<'tcx> {
+    fn describe(_tcx: TyCtxt, _: HirId) -> String {
+        format!("fetching the exported items for a module")
+    }
+}
+
 // If enabled, send a message to the profile-queries thread
 macro_rules! profq_msg {
     ($tcx:expr, $msg:expr) => {
@@ -1125,6 +1131,7 @@ define_maps! { <'tcx>
     [] lint_levels: lint_levels(CrateNum) -> Rc<lint::LintLevelMap>,
 
     [] in_scope_traits: InScopeTraits(HirId) -> Option<Rc<Vec<TraitCandidate>>>,
+    [] module_exports: ModuleExports(HirId) -> Option<Rc<Vec<Export>>>,
 }
 
 fn type_param_predicates<'tcx>((item_id, param_id): (DefId, DefId)) -> DepConstructor<'tcx> {

Diff for: src/librustc_metadata/encoder.rs

@@ -548,12 +548,13 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                                                                  &hir::Visibility)>)
                            -> Entry<'tcx> {
         let tcx = self.tcx;
+        let hir_id = tcx.hir.node_to_hir_id(id);
         let def_id = tcx.hir.local_def_id(id);
         debug!("IsolatedEncoder::encode_info_for_mod({:?})", def_id);
 
         let data = ModData {
-            reexports: match tcx.export_map.get(&id) {
-                Some(exports) if *vis == hir::Public => {
+            reexports: match tcx.module_exports(hir_id) {
+                Some(ref exports) if *vis == hir::Public => {
                     self.lazy_seq_from_slice(exports.as_slice())
                 }
                 _ => LazySeq::empty(),

Diff for: src/librustc_privacy/lib.rs

@@ -325,8 +325,9 @@ impl<'a, 'tcx> Visitor<'tcx> for EmbargoVisitor<'a, 'tcx> {
         // This code is here instead of in visit_item so that the
         // crate module gets processed as well.
         if self.prev_level.is_some() {
-            if let Some(exports) = self.tcx.export_map.get(&id) {
-                for export in exports {
+            let hir_id = self.tcx.hir.node_to_hir_id(id);
+            if let Some(exports) = self.tcx.module_exports(hir_id) {
+                for export in exports.iter() {
                     if let Some(node_id) = self.tcx.hir.as_local_node_id(export.def.def_id()) {
                         self.update(node_id, Some(AccessLevel::Exported));
                     }

Diff for: src/librustc_typeck/check/method/probe.rs

@@ -662,6 +662,9 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
     fn assemble_extension_candidates_for_traits_in_scope(&mut self,
                                                          expr_id: ast::NodeId)
                                                          -> Result<(), MethodError<'tcx>> {
+        if expr_id == ast::DUMMY_NODE_ID {
+            return Ok(())
+        }
         let mut duplicates = FxHashSet();
         let expr_hir_id = self.tcx.hir.node_to_hir_id(expr_id);
         let opt_applicable_traits = self.tcx.in_scope_traits(expr_hir_id);

Diff for: src/librustdoc/visit_ast.rs

@@ -199,8 +199,9 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
             self.visit_item(item, None, &mut om);
         }
         self.inside_public_path = orig_inside_public_path;
-        if let Some(exports) = self.cx.tcx.export_map.get(&id) {
-            for export in exports {
+        let hir_id = self.cx.tcx.hir.node_to_hir_id(id);
+        if let Some(exports) = self.cx.tcx.module_exports(hir_id) {
+            for export in exports.iter() {
                 if let Def::Macro(def_id, ..) = export.def {
                     if def_id.krate == LOCAL_CRATE || self.reexported_macros.contains(&def_id) {
                         continue // These are `krate.exported_macros`, handled in `self.visit()`.