[clangd] BackgroundIndex stores shards to the closest project

[kadircet]

Summary

Changes persistance logic to store shards at the directory of closest
CDB. Previously we were storing all shards to directory of the CDB that
triggered indexing, it had its downsides.

For example, if you had two TUs coming from a different CDB but depending on the
same header foo.h, we will store the foo.h only for the first CDB, and it would
be missing for the second and we would never persist it since it was actually
present in the memory and persisted before.

This patch still stores only a single copy of a shard, but makes the directory a
function of the file name. So that the shard place will be unique even with
multiple CDBs accessing the file. This directory is determined as the first
directory containing a CDB in the file's parent directories, if no such
directory exists we make use of the home directory.

[sammccall]

LG apart from the second global CDB

clang-tools-extra/clangd/index/BackgroundIndexStorage.cpp

128 ↗

(On Diff #209860)

Why does this have its own CDB? AFAICS it can use the shared CDB, possibly indirecting through a std::function

149 ↗

(On Diff #209860)

This assertion will be hit if home_directory() fails. It shouldn't, but... maybe keep the "return nullstorage" to cover this case (and also the assert?)

[kadircet]

• Address comments

[kadircet]

clang-tools-extra/clangd/index/BackgroundIndexStorage.cpp

149 ↗

(On Diff #209860)

elog'ing instead of assertion, since this indeed happens in one of our lit-tests

clang-tools-extra/trunk/clangd/ClangdServer.cpp

if (this->Index != nullptr) {
       this->Index = Idx;
     }
   };
   if (Opts.StaticIndex)
     AddIndex(Opts.StaticIndex);
   if (Opts.BackgroundIndex) {
     BackgroundIdx = llvm::make_unique<BackgroundIndex>(
         Context::current().clone(), FSProvider, CDB,
-        BackgroundIndexStorage::createDiskBackedStorageFactory());
+        BackgroundIndexStorage::createDiskBackedStorageFactory(
+            [&CDB](llvm::StringRef File) { return CDB.getProjectInfo(File); }));
     AddIndex(BackgroundIdx.get());
   }
   if (DynamicIdx)
     AddIndex(DynamicIdx.get());
 }
 
 void ClangdServer::addDocument(PathRef File, llvm::StringRef Contents,
                                WantDiagnostics WantDiags) {

clang-tools-extra/trunk/clangd/index/Background.h

public:
   virtual llvm::Error storeShard(llvm::StringRef ShardIdentifier,
                                  IndexFileOut Shard) const = 0;
 
   // Tries to load shard with given identifier, returns nullptr if shard
   // couldn't be loaded.
   virtual std::unique_ptr<IndexFileIn>
   loadShard(llvm::StringRef ShardIdentifier) const = 0;
 
-  // The factory provides storage for each CDB.
+  // The factory provides storage for each File.
   // It keeps ownership of the storage instances, and should manage caching
   // itself. Factory must be threadsafe and never returns nullptr.
-  using Factory =
-      llvm::unique_function<BackgroundIndexStorage *(llvm::StringRef)>;
+  using Factory = llvm::unique_function<BackgroundIndexStorage *(PathRef)>;
 
   // Creates an Index Storage that saves shards into disk. Index storage uses
-  // CDBDirectory + ".clangd/index/" as the folder to save shards.
-  static Factory createDiskBackedStorageFactory();
+  // CDBDirectory + ".clangd/index/" as the folder to save shards. CDBDirectory
+  // is the first directory containing a CDB in parent directories of a file, or
+  // user's home directory if none was found, e.g. standard library headers.
+  static Factory createDiskBackedStorageFactory(
+      std::function<llvm::Optional<ProjectInfo>(PathRef)> GetProjectInfo);
 };
 
 // A priority queue of tasks which can be run on (external) worker threads.
 class BackgroundQueue {
 public:
   /// A work item on the thread pool's queue.
   struct Task {
     explicit Task(std::function<void()> Run) : Run(std::move(Run)) {}
struct ShardVersion {
     bool HadErrors = false;
   };
 
   /// Given index results from a TU, only update symbols coming from files with
   /// different digests than \p ShardVersionsSnapshot. Also stores new index
   /// information on IndexStorage.
   void update(llvm::StringRef MainFile, IndexFileIn Index,
               const llvm::StringMap<ShardVersion> &ShardVersionsSnapshot,
-              BackgroundIndexStorage *IndexStorage, bool HadErrors);
+              bool HadErrors);
 
   // configuration
   const FileSystemProvider &FSProvider;
   const GlobalCompilationDatabase &CDB;
   Context BackgroundContext;
 
-  llvm::Error index(tooling::CompileCommand,
-                    BackgroundIndexStorage *IndexStorage);
+  llvm::Error index(tooling::CompileCommand);
 
   FileSymbols IndexedSymbols;
   BackgroundIndexRebuilder Rebuilder;
   llvm::StringMap<ShardVersion> ShardVersions; // Key is absolute file path.
   std::mutex ShardVersionsMu;
 
   BackgroundIndexStorage::Factory IndexStorageFactory;
   // Tries to load shards for the MainFiles and their dependencies.
-  std::vector<std::pair<tooling::CompileCommand, BackgroundIndexStorage *>>
+  std::vector<tooling::CompileCommand>
   loadProject(std::vector<std::string> MainFiles);
 
   BackgroundQueue::Task
   changedFilesTask(const std::vector<std::string> &ChangedFiles);
-  BackgroundQueue::Task indexFileTask(tooling::CompileCommand Cmd,
-                                      BackgroundIndexStorage *Storage);
+  BackgroundQueue::Task indexFileTask(tooling::CompileCommand Cmd);
 
   // from lowest to highest priority
   enum QueuePriority {
     IndexFile,
     IndexBoostedFile,
     LoadShards,
   };
   BackgroundQueue Queue;
   AsyncTaskRunner ThreadPool;
   GlobalCompilationDatabase::CommandChanged::Subscription CommandsChanged;
 };
 
 } // namespace clangd
 } // namespace clang
 
 #endif

clang-tools-extra/trunk/clangd/index/Background.cpp

BackgroundQueue::Task T([this, ChangedFiles] {
     SPAN_ATTACH(Tracer, "files", int64_t(ChangedFiles.size()));
 
     auto NeedsReIndexing = loadProject(std::move(ChangedFiles));
     // Run indexing for files that need to be updated.
     std::shuffle(NeedsReIndexing.begin(), NeedsReIndexing.end(),
                  std::mt19937(std::random_device{}()));
     std::vector<BackgroundQueue::Task> Tasks;
     Tasks.reserve(NeedsReIndexing.size());
-    for (auto &Elem : NeedsReIndexing)
-      Tasks.push_back(indexFileTask(std::move(Elem.first), Elem.second));
+    for (auto &Cmd : NeedsReIndexing)
+      Tasks.push_back(indexFileTask(std::move(Cmd)));
     Queue.append(std::move(Tasks));
   });
 
   T.QueuePri = LoadShards;
   T.ThreadPri = llvm::ThreadPriority::Default;
   return T;
 }
 
 static llvm::StringRef filenameWithoutExtension(llvm::StringRef Path) {
   Path = llvm::sys::path::filename(Path);
   return Path.drop_back(llvm::sys::path::extension(Path).size());
 }
 
 BackgroundQueue::Task
-BackgroundIndex::indexFileTask(tooling::CompileCommand Cmd,
-                               BackgroundIndexStorage *Storage) {
-  BackgroundQueue::Task T([this, Storage, Cmd] {
+BackgroundIndex::indexFileTask(tooling::CompileCommand Cmd) {
+  BackgroundQueue::Task T([this, Cmd] {
     // We can't use llvm::StringRef here since we are going to
     // move from Cmd during the call below.
     const std::string FileName = Cmd.Filename;
-    if (auto Error = index(std::move(Cmd), Storage))
+    if (auto Error = index(std::move(Cmd)))
       elog("Indexing {0} failed: {1}", FileName, std::move(Error));
   });
   T.QueuePri = IndexFile;
   T.Tag = filenameWithoutExtension(Cmd.Filename);
   return T;
 }
 
 void BackgroundIndex::boostRelated(llvm::StringRef Path) {
   namespace types = clang::driver::types;
   auto Type =
       types::lookupTypeForExtension(llvm::sys::path::extension(Path).substr(1));
   // is this a header?
   if (Type != types::TY_INVALID && types::onlyPrecompileType(Type))
     Queue.boost(filenameWithoutExtension(Path), IndexBoostedFile);
 }
 
 /// Given index results from a TU, only update symbols coming from files that
 /// are different or missing from than \p ShardVersionsSnapshot. Also stores new
 /// index information on IndexStorage.
 void BackgroundIndex::update(
     llvm::StringRef MainFile, IndexFileIn Index,
     const llvm::StringMap<ShardVersion> &ShardVersionsSnapshot,
-    BackgroundIndexStorage *IndexStorage, bool HadErrors) {
+    bool HadErrors) {
   // Partition symbols/references into files.
   struct File {
     llvm::DenseSet<const Symbol *> Symbols;
     llvm::DenseSet<const Ref *> Refs;
     llvm::DenseSet<const Relation *> Relations;
     FileDigest Digest;
   };
   llvm::StringMap<File> Files;
for (const auto &FileIt : Files) {
     auto RS = llvm::make_unique<RefSlab>(std::move(Refs).build());
     auto RelS = llvm::make_unique<RelationSlab>(std::move(Relations).build());
     auto IG = llvm::make_unique<IncludeGraph>(
         getSubGraph(URI::create(Path), Index.Sources.getValue()));
 
     // We need to store shards before updating the index, since the latter
     // consumes slabs.
     // FIXME: Also skip serializing the shard if it is already up-to-date.
-    if (IndexStorage) {
-      IndexFileOut Shard;
-      Shard.Symbols = SS.get();
-      Shard.Refs = RS.get();
-      Shard.Relations = RelS.get();
-      Shard.Sources = IG.get();
+    BackgroundIndexStorage *IndexStorage = IndexStorageFactory(Path);
 
-      // Only store command line hash for main files of the TU, since our
-      // current model keeps only one version of a header file.
-      if (Path == MainFile)
-        Shard.Cmd = Index.Cmd.getPointer();
 
-      if (auto Error = IndexStorage->storeShard(Path, Shard))
-        elog("Failed to write background-index shard for file {0}: {1}", Path,
-             std::move(Error));
-    }
 
     {
       std::lock_guard<std::mutex> Lock(ShardVersionsMu);
       auto Hash = FileIt.second.Digest;
       auto DigestIt = ShardVersions.try_emplace(Path);
       ShardVersion &SV = DigestIt.first->second;
       // Skip if file is already up to date, unless previous index was broken
       // and this one is not.
       if (!DigestIt.second && SV.Digest == Hash && SV.HadErrors && !HadErrors)
         continue;
       SV.Digest = Hash;
       SV.HadErrors = HadErrors;
 
       // This can override a newer version that is added in another thread, if
       // this thread sees the older version but finishes later. This should be
       // rare in practice.
       IndexedSymbols.update(Path, std::move(SS), std::move(RS), std::move(RelS),
                             Path == MainFile);
     }
   }
 }
 
-llvm::Error BackgroundIndex::index(tooling::CompileCommand Cmd,
-                                   BackgroundIndexStorage *IndexStorage) {
+llvm::Error BackgroundIndex::index(tooling::CompileCommand Cmd) {
   trace::Span Tracer("BackgroundIndex");
   SPAN_ATTACH(Tracer, "file", Cmd.Filename);
   auto AbsolutePath = getAbsolutePath(Cmd);
 
   auto FS = FSProvider.getFileSystem();
   auto Buf = FS->getBufferForFile(AbsolutePath);
   if (!Buf)
     return llvm::errorCodeToError(Buf.getError());
llvm::Error BackgroundIndex::index(tooling::CompileCommand Cmd) {
 
   bool HadErrors = Clang->hasDiagnostics() &&
                    Clang->getDiagnostics().hasUncompilableErrorOccurred();
   if (HadErrors) {
     log("Failed to compile {0}, index may be incomplete", AbsolutePath);
     for (auto &It : *Index.Sources)
       It.second.Flags |= IncludeGraphNode::SourceFlag::HadErrors;
   }
-  update(AbsolutePath, std::move(Index), ShardVersionsSnapshot, IndexStorage,
-         HadErrors);
+  update(AbsolutePath, std::move(Index), ShardVersionsSnapshot, HadErrors);
 
   Rebuilder.indexedTU();
   return llvm::Error::success();
 }
 
 // Restores shards for \p MainFiles from index storage. Then checks staleness of
 // those shards and returns a list of TUs that needs to be indexed to update
 // staleness.
-std::vector<std::pair<tooling::CompileCommand, BackgroundIndexStorage *>>
+std::vector<tooling::CompileCommand>
 BackgroundIndex::loadProject(std::vector<std::string> MainFiles) {
-  std::vector<std::pair<tooling::CompileCommand, BackgroundIndexStorage *>>
-      NeedsReIndexing;
+  std::vector<tooling::CompileCommand> NeedsReIndexing;
 
   Rebuilder.startLoading();
   // Load shards for all of the mainfiles.
   const std::vector<LoadedShard> Result =
       loadIndexShards(MainFiles, IndexStorageFactory, CDB);
   size_t LoadedShards = 0;
   {
     // Update in-memory state.
BackgroundIndex::loadProject(std::vector<std::string> MainFiles) {
 
   for (PathRef TU : TUsToIndex) {
     auto Cmd = CDB.getCompileCommand(TU);
     if (!Cmd)
       continue;
     std::string ProjectRoot;
     if (auto PI = CDB.getProjectInfo(TU))
       ProjectRoot = std::move(PI->SourceRoot);
-    BackgroundIndexStorage *Storage = IndexStorageFactory(ProjectRoot);
-    NeedsReIndexing.emplace_back(std::move(*Cmd), Storage);
+    NeedsReIndexing.emplace_back(std::move(*Cmd));
   }
 
   return NeedsReIndexing;
 }
 
 } // namespace clangd
 } // namespace clang

clang-tools-extra/trunk/clangd/index/BackgroundIndexLoader.cpp

if (!AbsolutePath)
     return llvm::None;
   return *AbsolutePath;
 }
 
 /// A helper class to cache BackgroundIndexStorage operations and keep the
 /// inverse dependency mapping.
 class BackgroundIndexLoader {
 public:
+  BackgroundIndexLoader(BackgroundIndexStorage::Factory &IndexStorageFactory)
+      : IndexStorageFactory(IndexStorageFactory) {}
   /// Load the shards for \p MainFile and all of its dependencies.
-  void load(PathRef MainFile, BackgroundIndexStorage *Storage);
+  void load(PathRef MainFile);
 
   /// Consumes the loader and returns all shards.
   std::vector<LoadedShard> takeResult() &&;
 
 private:
   /// Returns the Shard for \p StartSourceFile from cache or loads it from \p
   /// Storage. Also returns paths for dependencies of \p StartSourceFile if it
   /// wasn't cached yet.
   std::pair<const LoadedShard &, std::vector<Path>>
-  loadShard(PathRef StartSourceFile, BackgroundIndexStorage *Storage);
+  loadShard(PathRef StartSourceFile);
 
   /// Cache for Storage lookups.
   llvm::StringMap<LoadedShard> LoadedShards;
 
   /// References are into the AbsolutePaths in LoadedShards.
   llvm::DenseMap<PathRef, PathRef> FileToTU;
+
+  BackgroundIndexStorage::Factory &IndexStorageFactory;
 };
 
 std::pair<const LoadedShard &, std::vector<Path>>
-BackgroundIndexLoader::loadShard(PathRef StartSourceFile,
-                                 BackgroundIndexStorage *Storage) {
+BackgroundIndexLoader::loadShard(PathRef StartSourceFile) {
   auto It = LoadedShards.try_emplace(StartSourceFile);
   LoadedShard &LS = It.first->getValue();
   std::vector<Path> Edges = {};
   // Return the cached shard.
   if (!It.second)
     return {LS, Edges};
 
   LS.AbsolutePath = StartSourceFile.str();
+  BackgroundIndexStorage *Storage = IndexStorageFactory(LS.AbsolutePath);
   auto Shard = Storage->loadShard(StartSourceFile);
   if (!Shard || !Shard->Sources) {
     vlog("Failed to load shard: {0}", StartSourceFile);
     return {LS, Edges};
   }
 
   LS.Shard = std::move(Shard);
   for (const auto &It : *LS.Shard->Sources) {
for (const auto &It : *LS.Shard->Sources) {
     LS.Digest = IGN.Digest;
     LS.CountReferences = IGN.Flags & IncludeGraphNode::SourceFlag::IsTU;
     LS.HadErrors = IGN.Flags & IncludeGraphNode::SourceFlag::HadErrors;
   }
   assert(LS.Digest != FileDigest{{0}} && "Digest is empty?");
   return {LS, Edges};
 }
 
-void BackgroundIndexLoader::load(PathRef MainFile,
-                                 BackgroundIndexStorage *Storage) {
+void BackgroundIndexLoader::load(PathRef MainFile) {
   llvm::StringSet<> InQueue;
   // Following containers points to strings inside InQueue.
   std::queue<PathRef> ToVisit;
   InQueue.insert(MainFile);
   ToVisit.push(MainFile);
 
   while (!ToVisit.empty()) {
     PathRef SourceFile = ToVisit.front();
     ToVisit.pop();
 
-    auto ShardAndEdges = loadShard(SourceFile, Storage);
+    auto ShardAndEdges = loadShard(SourceFile);
     FileToTU[ShardAndEdges.first.AbsolutePath] = MainFile;
     for (PathRef Edge : ShardAndEdges.second) {
       auto It = InQueue.insert(Edge);
       if (It.second)
         ToVisit.push(It.first->getKey());
     }
   }
 }
std::vector<LoadedShard> BackgroundIndexLoader::takeResult() && {
   return Result;
 }
 } // namespace
 
 std::vector<LoadedShard>
 loadIndexShards(llvm::ArrayRef<Path> MainFiles,
                 BackgroundIndexStorage::Factory &IndexStorageFactory,
                 const GlobalCompilationDatabase &CDB) {
-  BackgroundIndexLoader Loader;
+  BackgroundIndexLoader Loader(IndexStorageFactory);
   for (llvm::StringRef MainFile : MainFiles) {
     assert(llvm::sys::path::is_absolute(MainFile));
-
-    std::string ProjectRoot;
-    if (auto PI = CDB.getProjectInfo(MainFile))
-      ProjectRoot = std::move(PI->SourceRoot);
-    BackgroundIndexStorage *Storage = IndexStorageFactory(ProjectRoot);
-    Loader.load(MainFile, Storage);
+    Loader.load(MainFile);
   }
   return std::move(Loader).takeResult();
 }
 
 } // namespace clangd
 } // namespace clang

clang-tools-extra/trunk/clangd/index/BackgroundIndexStorage.cpp

 //== BackgroundIndexStorage.cpp - Provide caching support to BackgroundIndex ==/
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
+#include "GlobalCompilationDatabase.h"
 #include "Logger.h"
+#include "Path.h"
 #include "index/Background.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/ScopeExit.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
+#include <functional>
 
 namespace clang {
 namespace clangd {
 namespace {
 
 std::string getShardPathFromFilePath(llvm::StringRef ShardRoot,
                                      llvm::StringRef FilePath) {
   llvm::SmallString<128> ShardRootSS(ShardRoot);
vlog("Couldn't find project for {0}, indexing in-memory only",
          ShardIdentifier);
     return llvm::Error::success();
   }
 };
 
 // Creates and owns IndexStorages for multiple CDBs.
 class DiskBackedIndexStorageManager {
 public:
-  DiskBackedIndexStorageManager()
-      : IndexStorageMapMu(llvm::make_unique<std::mutex>()) {}
+  DiskBackedIndexStorageManager(
+      std::function<llvm::Optional<ProjectInfo>(PathRef)> GetProjectInfo)
+      : IndexStorageMapMu(llvm::make_unique<std::mutex>()),
+        GetProjectInfo(std::move(GetProjectInfo)) {
+    llvm::SmallString<128> HomeDir;
+    llvm::sys::path::home_directory(HomeDir);
+    this->HomeDir = HomeDir.str().str();
+  }
 
-  // Creates or fetches to storage from cache for the specified CDB.
-  BackgroundIndexStorage *operator()(llvm::StringRef CDBDirectory) {
+  // Creates or fetches to storage from cache for the specified project.
+  BackgroundIndexStorage *operator()(PathRef File) {
     std::lock_guard<std::mutex> Lock(*IndexStorageMapMu);
+    Path CDBDirectory = HomeDir;
+    if (auto PI = GetProjectInfo(File))
+      CDBDirectory = PI->SourceRoot;
     auto &IndexStorage = IndexStorageMap[CDBDirectory];
     if (!IndexStorage)
       IndexStorage = create(CDBDirectory);
     return IndexStorage.get();
   }
 
 private:
-  std::unique_ptr<BackgroundIndexStorage> create(llvm::StringRef CDBDirectory) {
-    if (CDBDirectory.empty())
+  std::unique_ptr<BackgroundIndexStorage> create(PathRef CDBDirectory) {
+    if (CDBDirectory.empty()) {
+      elog("Tried to create storage for empty directory!");
       return llvm::make_unique<NullStorage>();
+    }
     return llvm::make_unique<DiskBackedIndexStorage>(CDBDirectory);
   }
 
+  Path HomeDir;
+
   llvm::StringMap<std::unique_ptr<BackgroundIndexStorage>> IndexStorageMap;
   std::unique_ptr<std::mutex> IndexStorageMapMu;
+
+  std::function<llvm::Optional<ProjectInfo>(PathRef)> GetProjectInfo;
 };
 
 } // namespace
 
 BackgroundIndexStorage::Factory
-BackgroundIndexStorage::createDiskBackedStorageFactory() {
-  return DiskBackedIndexStorageManager();
+BackgroundIndexStorage::createDiskBackedStorageFactory(
+    std::function<llvm::Optional<ProjectInfo>(PathRef)> GetProjectInfo) {
+  return DiskBackedIndexStorageManager(std::move(GetProjectInfo));
 }
 
 } // namespace clangd
 } // namespace clang

clang-tools-extra/trunk/clangd/test/Inputs/background-index/definition.jsonrpc

 {
   "jsonrpc": "2.0",
   "method": "textDocument/didOpen",
   "params": {
     "textDocument": {
       "uri": "file://DIRECTORY/bar.cpp",
       "languageId": "cpp",
       "version": 1,
-      "text": "#include \"foo.h\"\nint main(){\nreturn foo();\n}"
+      "text": "#include \"sub_dir/foo.h\"\nint main(){\nreturn foo();\n}"
     }
   }
 }
 ---
 {
   "jsonrpc": "2.0",
   "id": 1,
   "method": "sync",

clang-tools-extra/trunk/clangd/test/Inputs/background-index/foo.h

-#ifndef FOO_H
-#define FOO_H
-int foo();
-#endif

clang-tools-extra/trunk/clangd/test/Inputs/background-index/foo.cpp

-#include "foo.h"
+#include "sub_dir/foo.h"
 int foo() { return 42; }

clang-tools-extra/trunk/clangd/test/Inputs/background-index/sub_dir/foo.h

+#ifndef FOO_H
+#define FOO_H
+int foo();
+#endif

clang-tools-extra/trunk/clangd/test/background-index.test

 # We need to splice paths into file:// URIs for this test.
 # UNSUPPORTED: win32
 
 # Use a copy of inputs, as we'll mutate it (as will the background index).
 # RUN: rm -rf %t
 # RUN: cp -r %S/Inputs/background-index %t
 # Need to embed the correct temp path in the actual JSON-RPC requests.
-# RUN: sed -i -e "s|DIRECTORY|%t|" %t/*
+# RUN: sed -i -e "s|DIRECTORY|%t|" %t/definition.jsonrpc
+# RUN: sed -i -e "s|DIRECTORY|%t|" %t/compile_commands.json
 
 # We're editing bar.cpp, which includes foo.h.
 # foo() is declared in foo.h and defined in foo.cpp.
 # The background index should allow us to go-to-definition on foo().
 # RUN: clangd -background-index -lit-test < %t/definition.jsonrpc | FileCheck %t/definition.jsonrpc
 
 # Test that the index is writing files in the expected location.
 # RUN: ls %t/.clangd/index/foo.cpp.*.idx
+# RUN: ls %t/sub_dir/.clangd/index/foo.h.*.idx
 
 # Test the index is read from disk: delete code and restart clangd.
 # RUN: rm %t/foo.cpp
 # RUN: clangd -background-index -lit-test < %t/definition.jsonrpc | FileCheck %t/definition.jsonrpc