[clang-tools-extra] Implemented recursive search for findImplementations (PR #177564)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clangd

Author: None (timon-ul)

<details>
<summary>Changes</summary>

As described in [this comment](https://github.com/llvm/llvm-project/pull/177273#issuecomment-3787825323) this is a split of the PR since these changes can stand on their own.

---
Full diff: https://github.com/llvm/llvm-project/pull/177564.diff


2 Files Affected:

- (modified) clang-tools-extra/clangd/XRefs.cpp (+23-18) 
- (modified) clang-tools-extra/clangd/unittests/XRefsTests.cpp (+2-2) 


``````````diff
diff --git a/clang-tools-extra/clangd/XRefs.cpp b/clang-tools-extra/clangd/XRefs.cpp
index 8a24d19a7d129..dbc75c2868c47 100644
--- a/clang-tools-extra/clangd/XRefs.cpp
+++ b/clang-tools-extra/clangd/XRefs.cpp
@@ -306,25 +306,30 @@ std::vector<LocatedSymbol> findImplementors(llvm::DenseSet<SymbolID> IDs,
 
   RelationsRequest Req;
   Req.Predicate = Predicate;
-  Req.Subjects = std::move(IDs);
+  llvm::DenseSet<SymbolID> RecursiveSearch = std::move(IDs);
   std::vector<LocatedSymbol> Results;
-  Index->relations(Req, [&](const SymbolID &Subject, const Symbol &Object) {
-    auto DeclLoc =
-        indexToLSPLocation(Object.CanonicalDeclaration, MainFilePath);
-    if (!DeclLoc) {
-      elog("Find overrides: {0}", DeclLoc.takeError());
-      return;
-    }
-    Results.emplace_back();
-    Results.back().Name = Object.Name.str();
-    Results.back().PreferredDeclaration = *DeclLoc;
-    auto DefLoc = indexToLSPLocation(Object.Definition, MainFilePath);
-    if (!DefLoc) {
-      elog("Failed to convert location: {0}", DefLoc.takeError());
-      return;
-    }
-    Results.back().Definition = *DefLoc;
-  });
+  while (!RecursiveSearch.empty()) {
+    Req.Subjects = std::move(RecursiveSearch);
+    RecursiveSearch = {};
+    Index->relations(Req, [&](const SymbolID &Subject, const Symbol &Object) {
+      RecursiveSearch.insert(Object.ID);
+      auto DeclLoc =
+          indexToLSPLocation(Object.CanonicalDeclaration, MainFilePath);
+      if (!DeclLoc) {
+        elog("Find overrides: {0}", DeclLoc.takeError());
+        return;
+      }
+      Results.emplace_back();
+      Results.back().Name = Object.Name.str();
+      Results.back().PreferredDeclaration = *DeclLoc;
+      auto DefLoc = indexToLSPLocation(Object.Definition, MainFilePath);
+      if (!DefLoc) {
+        elog("Failed to convert location: {0}", DefLoc.takeError());
+        return;
+      }
+      Results.back().Definition = *DefLoc;
+    });
+  }
   return Results;
 }
 
diff --git a/clang-tools-extra/clangd/unittests/XRefsTests.cpp b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
index 4106c6cf7b2d0..0fd0f33500006 100644
--- a/clang-tools-extra/clangd/unittests/XRefsTests.cpp
+++ b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
@@ -1878,8 +1878,8 @@ TEST(FindImplementations, Inheritance) {
       virtual void B$2^ar();
       void Concrete();  // No implementations for concrete methods.
     };
-    struct Child2 : Child1 {
-      void $3[[Foo]]() override;
+    struct $0[[Child2]] : Child1 {
+      void $1[[$3[[Foo]]]]() override;
       void $2[[Bar]]() override;
     };
     void FromReference() {

``````````

</details>


https://github.com/llvm/llvm-project/pull/177564