Optimize import pipeline.

Previous implementation was slower at reindexing if loading from cache because primary cc files would be reindexed for every dependency that changed.

src/command_line.cc

@@ -744,7 +744,6 @@ struct Index_DoIndex {
     // of the dependencies. The main cc will then be parsed, which will include
     // updates to all dependencies.
 
-    ImportOnly,
     ImportThenParse,
     Parse,
     Freshen,
@@ -762,10 +761,13 @@ struct Index_DoIdMap {
   std::unique_ptr<IndexedFile> previous;
   std::unique_ptr<IndexedFile> current;
 
+  explicit Index_DoIdMap(std::unique_ptr<IndexedFile> current)
+    : current(std::move(current)) {}
+
   explicit Index_DoIdMap(std::unique_ptr<IndexedFile> previous,
-    std::unique_ptr<IndexedFile> current)
+                         std::unique_ptr<IndexedFile> current)
     : previous(std::move(previous)),
-    current(std::move(current)) {}
+      current(std::move(current)) {}
 };
 
 struct Index_OnIdMapped {
@@ -913,85 +915,83 @@ void RegisterMessageTypes() {
 
 
 
-void DispatchDependencyImports(Index_DoIndexQueue* queue_do_index,
-                               Index_DoIndex::Type request_type,
-                               const std::vector<std::string>& dependencies) {
-  // Import all dependencies.
-  for (auto& dependency_path : dependencies) {
-    std::cerr << "- Dispatching dependency import " << dependency_path << std::endl;
-    queue_do_index->PriorityEnqueue(Index_DoIndex(request_type, dependency_path, nullopt));
-  }
-}
-
-void ImportCachedIndex(IndexerConfig* config,
-                       Index_DoIndexQueue* queue_do_index,
+bool ImportCachedIndex(IndexerConfig* config,
+                       FileConsumer::SharedState* file_consumer_shared,
                        Index_DoIdMapQueue* queue_do_id_map,
-                       const std::string path,
-                       int64_t* last_modification_time) {
-  *last_modification_time = 0;
+                       const std::string& tu_path) {
+  // TODO: only load cache if command line arguments are the same.
 
   Timer time;
 
-  std::unique_ptr<IndexedFile> cache = LoadCachedIndex(config, path);
-  time.ResetAndPrint("Reading cached index from disk " + path);
+  std::unique_ptr<IndexedFile> cache = LoadCachedIndex(config, tu_path);
+  time.ResetAndPrint("Reading cached index from disk " + tu_path);
   if (!cache)
-    return;
+    return true;
 
-  DispatchDependencyImports(queue_do_index, Index_DoIndex::Type::ImportOnly, cache->dependencies);
+  bool needs_reparse = false;
 
-  *last_modification_time = cache->last_modification_time;
-  Index_DoIdMap response(nullptr, std::move(cache));
-  queue_do_id_map->Enqueue(std::move(response));
+  // Import all dependencies.
+  for (auto& dependency_path : cache->dependencies) {
+    std::cerr << "- Got dependency " << dependency_path << std::endl;
+    std::unique_ptr<IndexedFile> cache = LoadCachedIndex(config, dependency_path);
+    if (GetLastModificationTime(cache->path) == cache->last_modification_time)
+      file_consumer_shared->Mark(cache->path);
+    else
+      needs_reparse = true;
+    queue_do_id_map->Enqueue(Index_DoIdMap(std::move(cache)));
+  }
+
+  // Import primary file.
+  if (GetLastModificationTime(tu_path) == cache->last_modification_time)
+    file_consumer_shared->Mark(tu_path);
+  else
+    needs_reparse = true;
+  queue_do_id_map->Enqueue(Index_DoIdMap(std::move(cache)));
+
+  return needs_reparse;
 }
 
 void ParseFile(IndexerConfig* config,
                FileConsumer::SharedState* file_consumer_shared,
                Index_DoIdMapQueue* queue_do_id_map,
-               const std::string& path,
-               const optional<std::vector<std::string>>& args,
-               std::vector<std::string>* opt_out_dependencies) {
+               const std::string& tu_or_dep_path,
+               const optional<std::vector<std::string>>& args) {
   Timer time;
 
-  // Parse request and send a response.
-  std::unique_ptr<IndexedFile> cached_path_index = LoadCachedIndex(config, path);
+  std::unique_ptr<IndexedFile> cache_for_args = LoadCachedIndex(config, tu_or_dep_path);
 
-  if (cached_path_index) {
-    // Give the user dependencies if requested.
-    if (opt_out_dependencies)
-      *opt_out_dependencies = cached_path_index->dependencies;
-
-    // Skip index if file modification time didn't change.
-    int64_t modification_time = GetLastModificationTime(path);
-    if (modification_time == cached_path_index->last_modification_time) {
-      time.ResetAndPrint("Skipping index update on " + path + " since file modification time has not changed");
-      return;
-    }
-    else {
-      time.ResetAndPrint("Modification time on " + path + " has changed from " + std::to_string(cached_path_index->last_modification_time) + " to " + std::to_string(modification_time));
-    }
-  }
 
+  std::string tu_path = cache_for_args ? cache_for_args->import_file : tu_or_dep_path;
+  // TODO: Replace checking cache for arguments by guessing arguments on via directory structure. That will also work better for new files.
+  const std::vector<std::string>& tu_args = args ? *args : cache_for_args ? cache_for_args->args : kEmptyArgs;
   std::vector<std::unique_ptr<IndexedFile>> indexes = Parse(
     config, file_consumer_shared,
-    path, cached_path_index ? cached_path_index->import_file : path,
-    args ? *args : cached_path_index ? cached_path_index->args : kEmptyArgs);
-  time.ResetAndPrint("Parsing/indexing " + path);
+    tu_path, tu_args);
+  time.ResetAndPrint("Parsing/indexing " + tu_path + " with args " + StringJoin(tu_args));
 
   for (std::unique_ptr<IndexedFile>& new_index : indexes) {
     std::cerr << "Got index for " << new_index->path << std::endl;
 
     // Load the cached index.
     std::unique_ptr<IndexedFile> cached_index;
-    if (new_index->path == path)
-      cached_index = std::move(cached_path_index);
+    if (cache_for_args && new_index->path == cache_for_args->path)
+      cached_index = std::move(cache_for_args);
     else
       cached_index = LoadCachedIndex(config, new_index->path);
+    // TODO: Enable this assert when we are no longer forcibly indexing the primary file.
+    //assert(!cached_index || GetLastModificationTime(new_index->path) != cached_index->last_modification_time);
+
     time.ResetAndPrint("Loading cached index");
 
-    // Update dependencies on |new_index|, since they won't get reparsed if we
-    // have parsed them once before.
-    if (cached_index)
-      AddRange(&new_index->dependencies, cached_index->dependencies);
+    // Any any existing dependencies to |new_index| that were there before,
+    // because we will not reparse them if they haven't changed.
+    // TODO: indexer should always include dependencies. This doesn't let us remove old dependencies.
+    if (cached_index) {
+      for (auto& dep : cached_index->dependencies) {
+        if (std::find(new_index->dependencies.begin(), new_index->dependencies.end(), dep) == new_index->dependencies.end())
+          new_index->dependencies.push_back(dep);
+      }
+    }
 
     // Cache the newly indexed file. This replaces the existing cache.
     // TODO: Run this as another import pipeline stage.
@@ -1005,6 +1005,40 @@ void ParseFile(IndexerConfig* config,
 
 }
 
+bool ResetStaleFiles(IndexerConfig* config,
+                     FileConsumer::SharedState* file_consumer_shared,
+                     const std::string& tu_path) {
+  Timer time;
+
+  std::unique_ptr<IndexedFile> cache = LoadCachedIndex(config, tu_path);
+  time.ResetAndPrint("Reading cached index from disk " + tu_path);
+  if (!cache) {
+    std::cerr << "[indexer] Unable to load existing index from file when freshening (dependences will not be freshened)" << std::endl;
+    file_consumer_shared->Mark(tu_path);
+    return true;
+  }
+
+  bool needs_reparse = false;
+
+  // Check dependencies
+  for (auto& dependency_path : cache->dependencies) {
+    std::cerr << "- Got dependency " << dependency_path << std::endl;
+    std::unique_ptr<IndexedFile> cache = LoadCachedIndex(config, dependency_path);
+    if (GetLastModificationTime(cache->path) != cache->last_modification_time) {
+      needs_reparse = true;
+      file_consumer_shared->Reset(cache->path);
+    }
+  }
+
+  // Check primary file
+  if (GetLastModificationTime(tu_path) != cache->last_modification_time) {
+    needs_reparse = true;
+    file_consumer_shared->Mark(tu_path);
+  }
+
+  return needs_reparse;
+}
+
 bool IndexMain_DoIndex(IndexerConfig* config,
                        FileConsumer::SharedState* file_consumer_shared,
                        Project* project,
@@ -1017,18 +1051,14 @@ bool IndexMain_DoIndex(IndexerConfig* config,
   Timer time;
 
   switch (index_request->type) {
-    case Index_DoIndex::Type::ImportOnly: {
-      int64_t cache_modification_time;
-      ImportCachedIndex(config, queue_do_index, queue_do_id_map, index_request->path, &cache_modification_time);
-      break;
-    }
-
     case Index_DoIndex::Type::ImportThenParse: {
-      int64_t cache_modification_time;
-      ImportCachedIndex(config, queue_do_index, queue_do_id_map, index_request->path, &cache_modification_time);
+      // This assumes index_request->path is a cc or translation unit file (ie,
+      // it is in compile_commands.json).
+
+      bool needs_reparse = ImportCachedIndex(config, file_consumer_shared, queue_do_id_map, index_request->path);
 
       // If the file has been updated, we need to reparse it.
-      if (GetLastModificationTime(index_request->path) > cache_modification_time) {
+      if (needs_reparse) {
         // Instead of parsing the file immediately, we push the request to the
         // back of the queue so we will finish all of the Import requests
         // before starting to run actual index jobs. This gives the user a
@@ -1040,14 +1070,19 @@ bool IndexMain_DoIndex(IndexerConfig* config,
     }
 
     case Index_DoIndex::Type::Parse: {
-      ParseFile(config, file_consumer_shared, queue_do_id_map, index_request->path, index_request->args, nullptr);
+      // index_request->path can be a cc/tu or a dependency path.
+      file_consumer_shared->Reset(index_request->path);
+      ParseFile(config, file_consumer_shared, queue_do_id_map, index_request->path, index_request->args);
       break;
     }
 
     case Index_DoIndex::Type::Freshen: {
-      std::vector<std::string> dependencies;
-      ParseFile(config, file_consumer_shared, queue_do_id_map, index_request->path, index_request->args, &dependencies);
-      DispatchDependencyImports(queue_do_index, Index_DoIndex::Type::Freshen, dependencies);
+      // This assumes index_request->path is a cc or translation unit file (ie,
+      // it is in compile_commands.json).
+
+      bool needs_reparse = ResetStaleFiles(config, file_consumer_shared, index_request->path);
+      if (needs_reparse)
+        ParseFile(config, file_consumer_shared, queue_do_id_map, index_request->path, index_request->args);
       break;
     }
   }

src/file_consumer.cc

@@ -18,6 +18,18 @@ bool operator==(const CXFileUniqueID& a, const CXFileUniqueID& b) {
   return a.data[0] == b.data[0] && a.data[1] == b.data[1] && a.data[2] == b.data[2];
 }
 
+bool FileConsumer::SharedState::Mark(const std::string& file) {
+  std::lock_guard<std::mutex> lock(mutex);
+  return files.insert(file).second;
+}
+
+void FileConsumer::SharedState::Reset(const std::string& file) {
+  std::lock_guard<std::mutex> lock(mutex);
+  auto it = files.find(file);
+  if (it != files.end())
+    files.erase(it);
+}
+
 FileConsumer::FileConsumer(SharedState* shared_state) : shared_(shared_state) {}
 
 IndexedFile* FileConsumer::TryConsumeFile(CXFile file, bool* is_first_ownership) {
@@ -39,11 +51,7 @@ IndexedFile* FileConsumer::TryConsumeFile(CXFile file, bool* is_first_ownership)
   std::string file_name = FileName(file);
 
   // No result in local; we need to query global.
-  bool did_insert = false;
-  {
-    std::lock_guard<std::mutex> lock(shared_->mutex);
-    did_insert = shared_->files.insert(file_name).second;
-  }
+  bool did_insert = shared_->Mark(file_name);
   *is_first_ownership = did_insert;
   local_[file_id] = did_insert ? MakeUnique<IndexedFile>(file_name) : nullptr;
   return local_[file_id].get();

src/file_consumer.h

@@ -26,6 +26,11 @@ struct FileConsumer {
   struct SharedState {
     mutable std::unordered_set<std::string> files;
     mutable std::mutex mutex;
+
+    // Mark the file as used. Returns true if the file was not previously used.
+    bool Mark(const std::string& file);
+    // Reset the used state (ie, mark the file as unused).
+    void Reset(const std::string& file);
   };
 
   FileConsumer(SharedState* shared_state);

src/indexer.cc

@@ -1341,20 +1341,19 @@ void indexEntityReference(CXClientData client_data,
 
 std::vector<std::unique_ptr<IndexedFile>> Parse(
     IndexerConfig* config, FileConsumer::SharedState* file_consumer_shared,
-    std::string desired_index_file, std::string import_file,
+    std::string file,
     std::vector<std::string> args,
     bool dump_ast) {
 
   if (!config->enableIndexing)
     return {};
 
-  desired_index_file = NormalizePath(desired_index_file);
-  import_file = NormalizePath(import_file);
+  file = NormalizePath(file);
 
   clang::Index index(0 /*excludeDeclarationsFromPCH*/,
                      0 /*displayDiagnostics*/);
   std::vector<CXUnsavedFile> unsaved_files;
-  clang::TranslationUnit tu(config, index, import_file, args, unsaved_files, CXTranslationUnit_KeepGoing);
+  clang::TranslationUnit tu(config, index, file, args, unsaved_files, CXTranslationUnit_KeepGoing);
 
   if (dump_ast)
     Dump(tu.document_cursor());
@@ -1369,21 +1368,18 @@ std::vector<std::unique_ptr<IndexedFile>> Parse(
   FileConsumer file_consumer(file_consumer_shared);
   IndexParam param(&file_consumer);
 
-  CXFile file = clang_getFile(tu.cx_tu, desired_index_file.c_str());
-  param.primary_file = file_consumer.ForceLocal(file);
-  if (desired_index_file != import_file)
-    param.primary_file = nullptr;
+  // TODO: There is no real reason why we need |ForceLocal|. Remove it when we
+  // have argument guessing.
+  CXFile cx_file = clang_getFile(tu.cx_tu, file.c_str());
+  param.primary_file = file_consumer.ForceLocal(cx_file);
 
-  if (desired_index_file != import_file)
-    std::cerr << "!! [START] Indexing desired_index_file=" << desired_index_file << ", import_file=" << import_file << std::endl;
-  else
-    std::cerr << "!! [START] Indexing " << desired_index_file << std::endl;
+  std::cerr << "!! [START] Indexing " << file << std::endl;
   CXIndexAction index_action = clang_IndexAction_create(index.cx_index);
   clang_indexTranslationUnit(index_action, &param, callbacks, sizeof(callbacks),
                              CXIndexOpt_IndexFunctionLocalSymbols | CXIndexOpt_SkipParsedBodiesInSession | CXIndexOpt_IndexImplicitTemplateInstantiations,
                              tu.cx_tu);
   clang_IndexAction_dispose(index_action);
-  std::cerr << "!! [END] Indexing " << desired_index_file << std::endl;
+  std::cerr << "!! [END] Indexing " << file << std::endl;
 
   auto result = param.file_consumer->TakeLocalState();
   for (auto& entry : result) {
@@ -1395,7 +1391,7 @@ std::vector<std::unique_ptr<IndexedFile>> Parse(
     entry->id_cache.primary_file = entry->path;
 
     entry->last_modification_time = GetLastModificationTime(entry->path);
-    entry->import_file = import_file;
+    entry->import_file = file;
     entry->args = args;
   }
 
@@ -1403,21 +1399,21 @@ std::vector<std::unique_ptr<IndexedFile>> Parse(
   for (auto& entry : result) {
     for (auto& type : entry->types) {
       if (!type.HasInterestingState()) {
-        std::cerr << "!!!! NO INTERESTING STATE FOR " << entry->path << " of !!! " << desired_index_file << std::endl;
+        std::cerr << "!!!! NO INTERESTING STATE FOR " << entry->path << " of !!! " << file << std::endl;
         std::cerr << "!!!! USR " << type.def.usr << std::endl;
         assert(false);
       }
     }
     for (auto& func : entry->funcs) {
       if (!func.HasInterestingState()) {
-        std::cerr << "!!!! NO INTERESTING STATE FOR " << entry->path << " of !!! " << desired_index_file << std::endl;
+        std::cerr << "!!!! NO INTERESTING STATE FOR " << entry->path << " of !!! " << file << std::endl;
         std::cerr << "!!!! USR " << func.def.usr << std::endl;
         assert(false);
       }
     }
     for (auto& var : entry->vars) {
       if (!var.HasInterestingState()) {
-        std::cerr << "!!!! NO INTERESTING STATE FOR " << entry->path << " of !!! " << desired_index_file << std::endl;
+        std::cerr << "!!!! NO INTERESTING STATE FOR " << entry->path << " of !!! " << file << std::endl;
         std::cerr << "!!!! USR " << var.def.usr << std::endl;
         assert(false);
       }

src/indexer.h

@@ -503,7 +503,7 @@ struct IndexedFile {
 // |dependencies| are the existing dependencies of |import_file| if this is a reparse.
 std::vector<std::unique_ptr<IndexedFile>> Parse(
     IndexerConfig* config, FileConsumer::SharedState* file_consumer_shared,
-    std::string desired_index_file, std::string import_file,
+    std::string file,
     std::vector<std::string> args,
     bool dump_ast = false);
 void IndexInit();

src/test.cc

@@ -139,7 +139,7 @@ void RunTests() {
     std::cout << "[START] " << path << std::endl;
     std::vector<std::unique_ptr<IndexedFile>> dbs = Parse(
         &config, &file_consumer_shared,
-        path, path,
+        path,
         {
           "-xc++",
           "-std=c++11",

src/utils.cc

@@ -66,6 +66,18 @@ std::string ReplaceAll(const std::string& source, const std::string& from, const
   return result;
 }
 
+std::string StringJoin(const std::vector<std::string>& values) {
+  std::string result;
+  bool first = true;
+  for (auto& entry : values) {
+    if (!first)
+      result += ", ";
+    first = false;
+    result += entry;
+  }
+  return result;
+}
+
 static std::vector<std::string> GetFilesInFolderHelper(std::string folder, bool recursive, std::string output_prefix) {
   std::vector<std::string> result;
 

src/utils.h

@@ -18,6 +18,8 @@ bool StartsWith(const std::string& value, const std::string& start);
 bool EndsWith(const std::string& value, const std::string& ending);
 std::string ReplaceAll(const std::string& source, const std::string& from, const std::string& to);
 
+std::string StringJoin(const std::vector<std::string>& values);
+
 // Finds all files in the given folder. This is recursive.
 std::vector<std::string> GetFilesInFolder(std::string folder, bool recursive, bool add_folder_to_path);
 optional<std::string> ReadContent(const std::string& filename);