[clangd] Use ProjectAwareIndex in ClangdMain

Put project-aware-index between command-line specified static index and
ClangdServer indexes.

This also moves remote-index dependency from clangDaemon to ClangdMain
in an attempt to prevent cyclic dependency between clangDaemon and
remote-index-marshalling.

Differential Revision: https://reviews.llvm.org/D91860

clang-tools-extra/clangd/CMakeLists.txt

@@ -151,7 +151,6 @@ target_link_libraries(clangDaemon
   clangTidy
   ${ALL_CLANG_TIDY_CHECKS}
 
-  clangdRemoteIndex
   clangdSupport
   )
 

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

@@ -15,7 +15,6 @@
 #include "index/Serialization.h"
 #include "index/Symbol.h"
 #include "index/SymbolID.h"
-#include "index/remote/Client.h"
 #include "support/Logger.h"
 #include "support/Threading.h"
 #include "support/Trace.h"
@@ -124,33 +123,11 @@ SymbolIndex *ProjectAwareIndex::getIndex() const {
     Entry.first->getSecond() = Gen(External, Tasks);
   return Entry.first->second.get();
 }
-
-std::unique_ptr<SymbolIndex>
-defaultFactory(const Config::ExternalIndexSpec &External,
-               AsyncTaskRunner &Tasks) {
-  switch (External.Kind) {
-  case Config::ExternalIndexSpec::Server:
-    log("Associating {0} with remote index at {1}.", External.MountPoint,
-        External.Location);
-    return remote::getClient(External.Location, External.MountPoint);
-  case Config::ExternalIndexSpec::File:
-    log("Associating {0} with monolithic index at {1}.", External.MountPoint,
-        External.Location);
-    auto NewIndex = std::make_unique<SwapIndex>(std::make_unique<MemIndex>());
-    Tasks.runAsync("Load-index:" + External.Location,
-                   [File = External.Location, PlaceHolder = NewIndex.get()] {
-                     if (auto Idx = loadIndex(File, /*UseDex=*/true))
-                       PlaceHolder->reset(std::move(Idx));
-                   });
-    return std::move(NewIndex);
-  }
-  llvm_unreachable("Invalid ExternalIndexKind.");
-}
 } // namespace
 
 std::unique_ptr<SymbolIndex> createProjectAwareIndex(IndexFactory Gen) {
-  return std::make_unique<ProjectAwareIndex>(Gen ? std::move(Gen)
-                                                 : defaultFactory);
+  assert(Gen);
+  return std::make_unique<ProjectAwareIndex>(std::move(Gen));
 }
 } // namespace clangd
 } // namespace clang

clang-tools-extra/clangd/index/ProjectAware.h

@@ -23,11 +23,11 @@ namespace clangd {
 using IndexFactory = std::function<std::unique_ptr<SymbolIndex>(
     const Config::ExternalIndexSpec &, AsyncTaskRunner &)>;
 
-/// Returns an index that answers queries using external indices. IndexGenerator
-/// can be used to customize how to generate an index from an external source.
-/// The default implementation loads the index asynchronously on the
-/// AsyncTaskRunner. The index will appear empty until loaded.
-std::unique_ptr<SymbolIndex> createProjectAwareIndex(IndexFactory = nullptr);
+/// Returns an index that answers queries using external indices. IndexFactory
+/// specifies how to generate an index from an external source.
+/// IndexFactory must be injected because this code cannot depend on the remote
+/// index client.
+std::unique_ptr<SymbolIndex> createProjectAwareIndex(IndexFactory);
 } // namespace clangd
 } // namespace clang
 

clang-tools-extra/clangd/tool/ClangdMain.cpp

@@ -13,6 +13,9 @@
 #include "Protocol.h"
 #include "Transport.h"
 #include "index/Background.h"
+#include "index/Index.h"
+#include "index/Merge.h"
+#include "index/ProjectAware.h"
 #include "index/Serialization.h"
 #include "index/remote/Client.h"
 #include "refactor/Rename.h"
@@ -40,6 +43,7 @@
 #include <mutex>
 #include <string>
 #include <thread>
+#include <vector>
 
 #ifndef _WIN32
 #include <unistd.h>
@@ -551,6 +555,27 @@ const char TestScheme::TestDir[] = "C:\\clangd-test";
 const char TestScheme::TestDir[] = "/clangd-test";
 #endif
 
+std::unique_ptr<SymbolIndex>
+loadExternalIndex(const Config::ExternalIndexSpec &External,
+                  AsyncTaskRunner &Tasks) {
+  switch (External.Kind) {
+  case Config::ExternalIndexSpec::Server:
+    log("Associating {0} with remote index at {1}.", External.MountPoint,
+        External.Location);
+    return remote::getClient(External.Location, External.MountPoint);
+  case Config::ExternalIndexSpec::File:
+    log("Associating {0} with monolithic index at {1}.", External.MountPoint,
+        External.Location);
+    auto NewIndex = std::make_unique<SwapIndex>(std::make_unique<MemIndex>());
+    Tasks.runAsync("Load-index:" + External.Location,
+                   [File = External.Location, PlaceHolder = NewIndex.get()] {
+                     if (auto Idx = loadIndex(File, /*UseDex=*/true))
+                       PlaceHolder->reset(std::move(Idx));
+                   });
+    return std::move(NewIndex);
+  }
+  llvm_unreachable("Invalid ExternalIndexKind.");
+}
 } // namespace
 } // namespace clangd
 } // namespace clang
@@ -726,6 +751,7 @@ clangd accepts flags on the commandline, and in the CLANGD_FLAGS environment var
     Opts.ResourceDir = ResourceDir;
   Opts.BuildDynamicSymbolIndex = EnableIndex;
   Opts.CollectMainFileRefs = CollectMainFileRefs;
+  std::vector<std::unique_ptr<SymbolIndex>> IdxStack;
   std::unique_ptr<SymbolIndex> StaticIdx;
   std::future<void> AsyncIndexLoad; // Block exit while loading the index.
   if (EnableIndex && !IndexFile.empty()) {
@@ -757,7 +783,15 @@ clangd accepts flags on the commandline, and in the CLANGD_FLAGS environment var
   }
 #endif
   Opts.BackgroundIndex = EnableBackgroundIndex;
-  Opts.StaticIndex = StaticIdx.get();
+  auto PAI = createProjectAwareIndex(loadExternalIndex);
+  if (StaticIdx) {
+    IdxStack.emplace_back(std::move(StaticIdx));
+    IdxStack.emplace_back(
+        std::make_unique<MergedIndex>(PAI.get(), IdxStack.back().get()));
+    Opts.StaticIndex = IdxStack.back().get();
+  } else {
+    Opts.StaticIndex = PAI.get();
+  }
   Opts.AsyncThreadsCount = WorkerThreadsCount;
   Opts.BuildRecoveryAST = RecoveryAST;
   Opts.PreserveRecoveryASTType = RecoveryASTType;