Auto merge of #143247 - cjgillot:metadata-no-red, r=<try>

Avoid depending on forever-red DepNode when encoding metadata.

Split from #114669 for perf

r? `@petrochenkov`

Author: bors

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1600,6 +1600,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 let table = tcx.associated_types_for_impl_traits_in_associated_fn(def_id);
                 record_defaulted_array!(self.tables.associated_types_for_impl_traits_in_associated_fn[def_id] <- table);
             }
+            if let DefKind::Mod = tcx.def_kind(def_id) {
+                record!(self.tables.doc_link_resolutions[def_id] <- tcx.doc_link_resolutions(def_id));
+                record_array!(self.tables.doc_link_traits_in_scope[def_id] <- tcx.doc_link_traits_in_scope(def_id));
+            }
         }
 
         for (def_id, impls) in &tcx.crate_inherent_impls(()).0.inherent_impls {
@@ -1608,14 +1612,6 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 def_id.index
             }));
         }
-
-        for (def_id, res_map) in &tcx.resolutions(()).doc_link_resolutions {
-            record!(self.tables.doc_link_resolutions[def_id.to_def_id()] <- res_map);
-        }
-
-        for (def_id, traits) in &tcx.resolutions(()).doc_link_traits_in_scope {
-            record_array!(self.tables.doc_link_traits_in_scope[def_id.to_def_id()] <- traits);
-        }
     }
 
     #[instrument(level = "trace", skip(self))]

compiler/rustc_middle/src/query/mod.rs

@@ -204,6 +204,16 @@ rustc_queries! {
         desc { "getting the resolver for lowering" }
     }
 
+    /// Named module children from all kinds of items, including imports.
+    /// In addition to regular items this list also includes struct and variant constructors, and
+    /// items inside `extern {}` blocks because all of them introduce names into parent module.
+    ///
+    /// Module here is understood in name resolution sense - it can be a `mod` item,
+    /// or a crate root, or an enum, or a trait.
+    query module_children_local(key: LocalDefId) -> &'tcx [ModChild] {
+        desc { |tcx| "module exports for `{}`", tcx.def_path_str(key) }
+    }
+
     /// Return the span for a definition.
     ///
     /// Contrary to `def_span` below, this query returns the full absolute span of the definition.

compiler/rustc_middle/src/ty/context.rs

@@ -63,7 +63,6 @@ use crate::arena::Arena;
 use crate::dep_graph::{DepGraph, DepKindStruct};
 use crate::infer::canonical::{CanonicalParamEnvCache, CanonicalVarKind, CanonicalVarKinds};
 use crate::lint::lint_level;
-use crate::metadata::ModChild;
 use crate::middle::codegen_fn_attrs::{CodegenFnAttrs, TargetFeature};
 use crate::middle::{resolve_bound_vars, stability};
 use crate::mir::interpret::{self, Allocation, ConstAllocation};
@@ -2081,9 +2080,8 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn iter_local_def_id(self) -> impl Iterator<Item = LocalDefId> {
-        // Create a dependency to the red node to be sure we re-execute this when the amount of
-        // definitions change.
-        self.dep_graph.read_index(DepNodeIndex::FOREVER_RED_NODE);
+        // Depend on the `analysis` query to ensure compilation if finished.
+        self.ensure_ok().analysis(());
 
         let definitions = &self.untracked.definitions;
         gen {
@@ -2103,9 +2101,8 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn def_path_table(self) -> &'tcx rustc_hir::definitions::DefPathTable {
-        // Create a dependency to the crate to be sure we re-execute this when the amount of
-        // definitions change.
-        self.dep_graph.read_index(DepNodeIndex::FOREVER_RED_NODE);
+        // Depend on the `analysis` query to ensure compilation if finished.
+        self.ensure_ok().analysis(());
 
         // Freeze definitions once we start iterating on them, to prevent adding new ones
         // while iterating. If some query needs to add definitions, it should be `ensure`d above.
@@ -3372,19 +3369,6 @@ impl<'tcx> TyCtxt<'tcx> {
         self.opt_rpitit_info(def_id).is_some()
     }
 
-    /// Named module children from all kinds of items, including imports.
-    /// In addition to regular items this list also includes struct and variant constructors, and
-    /// items inside `extern {}` blocks because all of them introduce names into parent module.
-    ///
-    /// Module here is understood in name resolution sense - it can be a `mod` item,
-    /// or a crate root, or an enum, or a trait.
-    ///
-    /// This is not a query, making it a query causes perf regressions
-    /// (probably due to hashing spans in `ModChild`ren).
-    pub fn module_children_local(self, def_id: LocalDefId) -> &'tcx [ModChild] {
-        self.resolutions(()).module_children.get(&def_id).map_or(&[], |v| &v[..])
-    }
-
     pub fn resolver_for_lowering(self) -> &'tcx Steal<(ty::ResolverAstLowering, Arc<ast::Crate>)> {
         self.resolver_for_lowering_raw(()).0
     }
@@ -3436,6 +3420,8 @@ pub struct DeducedParamAttrs {
 }
 
 pub fn provide(providers: &mut Providers) {
+    providers.module_children_local =
+        |tcx, def_id| tcx.resolutions(()).module_children.get(&def_id).map_or(&[], |v| &v[..]);
     providers.maybe_unused_trait_imports =
         |tcx, ()| &tcx.resolutions(()).maybe_unused_trait_imports;
     providers.names_imported_by_glob_use = |tcx, id| {

compiler/rustc_resolve/src/late.rs

@@ -1559,12 +1559,17 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
     }
 
     fn with_mod_rib<T>(&mut self, id: NodeId, f: impl FnOnce(&mut Self) -> T) -> T {
-        let module = self.r.expect_module(self.r.local_def_id(id).to_def_id());
+        let def_id = self.r.local_def_id(id);
+        let module = self.r.expect_module(def_id.to_def_id());
         // Move down in the graph.
         let orig_module = replace(&mut self.parent_scope.module, module);
         self.with_rib(ValueNS, RibKind::Module(module), |this| {
             this.with_rib(TypeNS, RibKind::Module(module), |this| {
                 let ret = f(this);
+                // Make sure there is an entry in these maps, so metadata encoder does not need to
+                // understand in which case they are populated.
+                this.r.doc_link_resolutions.entry(def_id).or_default();
+                this.r.doc_link_traits_in_scope.entry(def_id).or_default();
                 this.parent_scope.module = orig_module;
                 ret
             })
@@ -5247,6 +5252,10 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 BuiltinLintDiag::UnusedLabel,
             );
         }
+        // Make sure there is an entry in these maps, so metadata encoder does not need to
+        // understand in which case they are populated.
+        self.doc_link_resolutions.entry(CRATE_DEF_ID).or_default();
+        self.doc_link_traits_in_scope.entry(CRATE_DEF_ID).or_default();
     }
 }