resolve: Do not cache nearest parent mod in ModuleData

petrochenkov · petrochenkov · commit 8443ea9a1499 · 2021-09-14T00:31:54.000+03:00
diff --git a/compiler/rustc_resolve/src/build_reduced_graph.rs b/compiler/rustc_resolve/src/build_reduced_graph.rs
@@ -146,7 +146,6 @@ impl<'a> Resolver<'a> {
         let module = self.arenas.alloc_module(ModuleData::new(
             parent,
             kind,
-            def_id,
             self.cstore().module_expansion_untracked(def_id, &self.session),
             self.cstore().get_span_untracked(def_id, &self.session),
         ));
@@ -274,7 +273,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                         self.r.visibilities[&def_id.expect_local()]
                     }
                     // Otherwise, the visibility is restricted to the nearest parent `mod` item.
-                    _ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod),
+                    _ => ty::Visibility::Restricted(self.parent_scope.module.nearest_parent_mod()),
                 })
             }
             ast::VisibilityKind::Restricted { ref path, id, .. } => {
@@ -773,13 +772,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                     no_implicit_prelude: parent.no_implicit_prelude || {
                         self.r.session.contains_name(&item.attrs, sym::no_implicit_prelude)
                     },
-                    ..ModuleData::new(
-                        Some(parent),
-                        module_kind,
-                        def_id,
-                        expansion.to_expn_id(),
-                        item.span,
-                    )
+                    ..ModuleData::new(Some(parent), module_kind, expansion.to_expn_id(), item.span)
                 });
                 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
                 self.r.module_map.insert(local_def_id, module);
@@ -814,13 +807,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
 
             ItemKind::Enum(_, _) => {
                 let module_kind = ModuleKind::Def(DefKind::Enum, def_id, ident.name);
-                let module = self.r.new_module(
-                    parent,
-                    module_kind,
-                    parent.nearest_parent_mod,
-                    expansion.to_expn_id(),
-                    item.span,
-                );
+                let module =
+                    self.r.new_module(parent, module_kind, expansion.to_expn_id(), item.span);
                 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
                 self.parent_scope.module = module;
             }
@@ -889,13 +877,8 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             ItemKind::Trait(..) => {
                 // Add all the items within to a new module.
                 let module_kind = ModuleKind::Def(DefKind::Trait, def_id, ident.name);
-                let module = self.r.new_module(
-                    parent,
-                    module_kind,
-                    parent.nearest_parent_mod,
-                    expansion.to_expn_id(),
-                    item.span,
-                );
+                let module =
+                    self.r.new_module(parent, module_kind, expansion.to_expn_id(), item.span);
                 self.r.define(parent, ident, TypeNS, (module, vis, sp, expansion));
                 self.parent_scope.module = module;
             }
@@ -935,7 +918,6 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
             let module = self.r.new_module(
                 parent,
                 ModuleKind::Block(block.id),
-                parent.nearest_parent_mod,
                 expansion.to_expn_id(),
                 block.span,
             );
@@ -956,7 +938,6 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                 let module = self.r.new_module(
                     parent,
                     ModuleKind::Def(kind, def_id, ident.name),
-                    def_id,
                     expansion.to_expn_id(),
                     span,
                 );
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
@@ -1872,7 +1872,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             if this.should_report_errs() {
                 let (err, candidates) = this.smart_resolve_report_errors(path, span, source, res);
 
-                let def_id = this.parent_scope.module.nearest_parent_mod;
+                let def_id = this.parent_scope.module.nearest_parent_mod();
                 let instead = res.is_some();
                 let suggestion =
                     if res.is_none() { this.report_missing_type_error(path) } else { None };
@@ -1940,7 +1940,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
             drop(parent_err);
 
-            let def_id = this.parent_scope.module.nearest_parent_mod;
+            let def_id = this.parent_scope.module.nearest_parent_mod();
 
             if this.should_report_errs() {
                 this.r.use_injections.push(UseError {
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
@@ -505,10 +505,6 @@ pub struct ModuleData<'a> {
     /// What kind of module this is, because this may not be a `mod`.
     kind: ModuleKind,
 
-    /// The [`DefId`] of the nearest `mod` item ancestor (which may be this module).
-    /// This may be the crate root.
-    nearest_parent_mod: DefId,
-
     /// Mapping between names and their (possibly in-progress) resolutions in this module.
     /// Resolutions in modules from other crates are not populated until accessed.
     lazy_resolutions: Resolutions<'a>,
@@ -536,19 +532,16 @@ pub struct ModuleData<'a> {
 type Module<'a> = &'a ModuleData<'a>;
 
 impl<'a> ModuleData<'a> {
-    fn new(
-        parent: Option<Module<'a>>,
-        kind: ModuleKind,
-        nearest_parent_mod: DefId,
-        expansion: ExpnId,
-        span: Span,
-    ) -> Self {
+    fn new(parent: Option<Module<'a>>, kind: ModuleKind, expansion: ExpnId, span: Span) -> Self {
+        let is_foreign = match kind {
+            ModuleKind::Def(_, def_id, _) => !def_id.is_local(),
+            ModuleKind::Block(_) => false,
+        };
         ModuleData {
             parent,
             kind,
-            nearest_parent_mod,
             lazy_resolutions: Default::default(),
-            populate_on_access: Cell::new(!nearest_parent_mod.is_local()),
+            populate_on_access: Cell::new(is_foreign),
             unexpanded_invocations: Default::default(),
             no_implicit_prelude: false,
             glob_importers: RefCell::new(Vec::new()),
@@ -559,6 +552,13 @@ impl<'a> ModuleData<'a> {
         }
     }
 
+    fn nearest_parent_mod(&self) -> DefId {
+        match self.kind {
+            ModuleKind::Def(DefKind::Mod, def_id, _) => def_id,
+            _ => self.parent.expect("non-root module without parent").nearest_parent_mod(),
+        }
+    }
+
     fn for_each_child<R, F>(&'a self, resolver: &mut R, mut f: F)
     where
         R: AsMut<Resolver<'a>>,
@@ -1260,18 +1260,12 @@ impl<'a> Resolver<'a> {
         let root_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
         let graph_root = arenas.alloc_module(ModuleData {
             no_implicit_prelude: session.contains_name(&krate.attrs, sym::no_implicit_prelude),
-            ..ModuleData::new(None, root_module_kind, root_def_id, ExpnId::root(), krate.span)
+            ..ModuleData::new(None, root_module_kind, ExpnId::root(), krate.span)
         });
         let empty_module_kind = ModuleKind::Def(DefKind::Mod, root_def_id, kw::Empty);
         let empty_module = arenas.alloc_module(ModuleData {
             no_implicit_prelude: true,
-            ..ModuleData::new(
-                Some(graph_root),
-                empty_module_kind,
-                root_def_id,
-                ExpnId::root(),
-                DUMMY_SP,
-            )
+            ..ModuleData::new(Some(graph_root), empty_module_kind, ExpnId::root(), DUMMY_SP)
         });
         let mut module_map = FxHashMap::default();
         module_map.insert(root_local_def_id, graph_root);
@@ -1636,11 +1630,10 @@ impl<'a> Resolver<'a> {
         &self,
         parent: Module<'a>,
         kind: ModuleKind,
-        nearest_parent_mod: DefId,
         expn_id: ExpnId,
         span: Span,
     ) -> Module<'a> {
-        let module = ModuleData::new(Some(parent), kind, nearest_parent_mod, expn_id, span);
+        let module = ModuleData::new(Some(parent), kind, expn_id, span);
         self.arenas.alloc_module(module)
     }
 
@@ -2167,7 +2160,8 @@ impl<'a> Resolver<'a> {
                 return self.graph_root;
             }
         };
-        let module = self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod });
+        let module =
+            self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.nearest_parent_mod() });
         debug!(
             "resolve_crate_root({:?}): got module {:?} ({:?}) (ident.span = {:?})",
             ident,
@@ -2179,10 +2173,10 @@ impl<'a> Resolver<'a> {
     }
 
     fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
-        let mut module = self.get_module(module.nearest_parent_mod);
+        let mut module = self.get_module(module.nearest_parent_mod());
         while module.span.ctxt().normalize_to_macros_2_0() != *ctxt {
             let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
-            module = self.get_module(parent.nearest_parent_mod);
+            module = self.get_module(parent.nearest_parent_mod());
         }
         module
     }
@@ -2896,7 +2890,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
-        vis.is_accessible_from(module.nearest_parent_mod, self)
+        vis.is_accessible_from(module.nearest_parent_mod(), self)
     }
 
     fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
@@ -2920,7 +2914,7 @@ impl<'a> Resolver<'a> {
             self.binding_parent_modules.get(&PtrKey(modularized)),
         ) {
             (Some(macro_rules), Some(modularized)) => {
-                macro_rules.nearest_parent_mod == modularized.nearest_parent_mod
+                macro_rules.nearest_parent_mod() == modularized.nearest_parent_mod()
                     && modularized.is_ancestor_of(macro_rules)
             }
             _ => false,
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
@@ -305,7 +305,7 @@ impl<'a> ResolverExpand for Resolver<'a> {
                 fast_print_path(path),
                 res.opt_def_id(),
                 res.opt_def_id().map(|macro_def_id| {
-                    self.macro_def_scope_from_def_id(macro_def_id).nearest_parent_mod
+                    self.macro_def_scope_from_def_id(macro_def_id).nearest_parent_mod()
                 }),
             ),
             self.create_stable_hashing_context(),
