resolve: Fill effective visibilities for import def ids in a separate pass

This should result in less update calls than doing it repeatedly during the fix point iteration.

1 files changed, 28 insertions, 2 deletions

diff --git a/compiler/rustc_middle/src/middle/privacy.rs b/compiler/rustc_middle/src/middle/privacy.rs
index 11fbefefcc9..3a91522d362 100644
--- a/compiler/rustc_middle/src/middle/privacy.rs
+++ b/compiler/rustc_middle/src/middle/privacy.rs
@@ -113,8 +113,30 @@ impl EffectiveVisibilities {
         })
     }
 
-    pub fn iter(&self) -> impl Iterator<Item = (&LocalDefId, &EffectiveVisibility)> {
-        self.map.iter()
+    // FIXME: Share code with `fn update`.
+    pub fn update_eff_vis(
+        &mut self,
+        def_id: LocalDefId,
+        eff_vis: &EffectiveVisibility,
+        tree: impl DefIdTree,
+    ) {
+        use std::collections::hash_map::Entry;
+        match self.map.entry(def_id) {
+            Entry::Occupied(mut occupied) => {
+                let old_eff_vis = occupied.get_mut();
+                for l in Level::all_levels() {
+                    let vis_at_level = eff_vis.at_level(l);
+                    let old_vis_at_level = old_eff_vis.at_level_mut(l);
+                    if vis_at_level != old_vis_at_level
+                        && vis_at_level.is_at_least(*old_vis_at_level, tree)
+                    {
+                        *old_vis_at_level = *vis_at_level
+                    }
+                }
+                old_eff_vis
+            }
+            Entry::Vacant(vacant) => vacant.insert(*eff_vis),
+        };
     }
 
     pub fn set_public_at_level(
@@ -185,6 +207,10 @@ impl EffectiveVisibilities {
 }
 
 impl<Id: Eq + Hash> EffectiveVisibilities<Id> {
+    pub fn iter(&self) -> impl Iterator<Item = (&Id, &EffectiveVisibility)> {
+        self.map.iter()
+    }
+
     pub fn effective_vis(&self, id: Id) -> Option<&EffectiveVisibility> {
         self.map.get(&id)
     }