1 files changed, 26 insertions, 0 deletions
diff --git a/clang-tools-extra/clangd/index/Merge.cpp b/clang-tools-extra/clangd/index/Merge.cpp
index aecca38..625b1c6 100644
--- a/clang-tools-extra/clangd/index/Merge.cpp
+++ b/clang-tools-extra/clangd/index/Merge.cpp
@@ -221,6 +221,32 @@ void MergedIndex::relations(
   });
 }
 
+void MergedIndex::reverseRelations(
+    const RelationsRequest &Req,
+    llvm::function_ref<void(const SymbolID &, const Symbol &)> Callback) const {
+  uint32_t Remaining = Req.Limit.value_or(std::numeric_limits<uint32_t>::max());
+  // Return results from both indexes but avoid duplicates.
+  // We might return stale relations from the static index;
+  // we don't currently have a good way of identifying them.
+  llvm::DenseSet<std::pair<SymbolID, SymbolID>> SeenRelations;
+  Dynamic->reverseRelations(
+      Req, [&](const SymbolID &Subject, const Symbol &Object) {
+        Callback(Subject, Object);
+        SeenRelations.insert(std::make_pair(Subject, Object.ID));
+        --Remaining;
+      });
+  if (Remaining == 0)
+    return;
+  Static->reverseRelations(
+      Req, [&](const SymbolID &Subject, const Symbol &Object) {
+        if (Remaining > 0 &&
+            !SeenRelations.count(std::make_pair(Subject, Object.ID))) {
+          --Remaining;
+          Callback(Subject, Object);
+        }
+      });
+}
+
 // Returns true if \p L is (strictly) preferred to \p R (e.g. by file paths). If
 // neither is preferred, this returns false.
 static bool prefer(const SymbolLocation &L, const SymbolLocation &R) {