[clangd] Add option to use remote index as static index

[kbobyrev]

Remove unintended change.

[kbobyrev]

Just stash changes, this is not a patch that is ready for a review.

[kbobyrev]

Don't touch Marshalling.cpp

[kbobyrev]

Remove remaining changes from Marshalling.cpp

[kbobyrev]

Still WIP, stashing changes.

[kbobyrev]

Add flag description.

[kbobyrev]

Rebase on top of master.

[hokein]

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

456

not sure whether we need a new category, probably can live in Features?

458

since we hide this in the CLANGD_ENABLE_REMOTE flag, maybe remove the Hidden?

462

maybe ProjectRoot?

699

the new code section here should be guarded under #ifdef CLANGD_ENABLE_REMOTE

704

if remote-index is on, should we turn off the background index? I think this is our plan, right?

706

nit: use elog.

708

instead of exiting clangd, maybe just continue (since this is not a fatal error), and adjust the error message stating that index-file option is ignored.

[kbobyrev]

Address review comments.

[kbobyrev]

Remove unused Remote category.

[hokein]

mostly good, just a concern about the linking dependence.

clang-tools-extra/clangd/CMakeLists.txt

143 ↗

(On Diff #280593)

the dependence here seems to be a layer violation. we add remote-index library when linking the clangDaemon, but clangdRemoteIndex *depends* on clangDaemon

I think we should do this when linking the clangd binary (in clangd/tool/CMakeLists.txt).

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

462

nit: project-path -> project-root.

[kbobyrev]

Resolve more comments.

[hokein]

looks good, thanks.

[hans]

clang-tools-extra/clangd/Features.inc.in

2

I'm guessing this should be @CLANGD_ENABLE_REMOTE@
The gn build was upset: http://45.33.8.238/linux/23942/step_4.txt
Speculatively fixed in 47a0254229ca425aa4e169c2db14e92b8db86784. Please shout if this was wrong.

[hans]

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

699

I think it should be an #if since the macro is always defined (0 or 1). Doing that in 40d11a878044711708fb6738e4b78a4c9ac3de7b

[thakis]

clang-tools-extra/clangd/Features.inc.in

2

Also, you probably either want #cmakedefine or you want to check with #if instead of #ifdef below. As-is, in the disabled case this will write #define CLANGD_ENABLE_REMOTE 0 in the disabled case, which causes the #ifdef to activate.

clang-tools-extra/clangd/Features.inc.in

 #define CLANGD_BUILD_XPC @CLANGD_BUILD_XPC@
+#define CLANGD_ENABLE_REMOTE @CLANGD_ENABLE_REMTE@

clang-tools-extra/clangd/tool/CMakeLists.txt

clang_target_link_libraries(clangd
   clangFormat
   clangFrontend
   clangLex
   clangSema
   clangTooling
   clangToolingCore
   clangToolingRefactoring
   clangToolingSyntax
+  clangdRemoteIndex
   )
 target_link_libraries(clangd
   PRIVATE
   clangTidy
   clangDaemon
   clangdSupport
   ${CLANGD_XPC_LIBS}
   )

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

 //===--- ClangdMain.cpp - clangd server loop ------------------------------===//
 //
 // 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 "ClangdLSPServer.h"
 #include "CodeComplete.h"
 #include "Features.inc"
 #include "PathMapping.h"
 #include "Protocol.h"
 #include "Transport.h"
 #include "index/Background.h"
 #include "index/Serialization.h"
+#include "index/remote/Client.h"
 #include "refactor/Rename.h"
 #include "support/Path.h"
 #include "support/Shutdown.h"
 #include "support/ThreadsafeFS.h"
 #include "support/Trace.h"
 #include "clang/Basic/Version.h"
 #include "clang/Format/Format.h"
 #include "llvm/ADT/Optional.h"
desc(
         "User config is from clangd/config.yaml in the following directories:\n"
         "\tWindows: %USERPROFILE%\\AppData\\Local\n"
         "\tMac OS: ~/Library/Preferences/\n"
         "\tOthers: $XDG_CONFIG_HOME, usually ~/.config\n"
         "Configuration is documented at https://clangd.llvm.org/config.html"),
     init(true),
 };
 
+#ifdef CLANGD_ENABLE_REMOTE
+opt<std::string> RemoteIndexAddress{
+    "remote-index-address",
+    cat(Features),
+    desc("Address of the remote index server"),
+};
+
+// FIXME(kirillbobyrev): Should this be the location of compile_commands.json?
+opt<std::string> ProjectRoot{
+    "project-root",
+    cat(Features),
+    desc("Path to the project root. Requires remote-index-address to be set."),
+};
+#endif
+
 /// Supports a test URI scheme with relaxed constraints for lit tests.
 /// The path in a test URI will be combined with a platform-specific fake
 /// directory to form an absolute path. For example, test:///a.cpp is resolved
 /// C:\clangd-test\a.cpp on Windows and /clangd-test/a.cpp on Unix.
 class TestScheme : public URIScheme {
 public:
   llvm::Expected<std::string>
   getAbsolutePath(llvm::StringRef /*Authority*/, llvm::StringRef Body,
if (EnableIndex && !IndexFile.empty()) {
     StaticIdx.reset(Placeholder = new SwapIndex(std::make_unique<MemIndex>()));
     AsyncIndexLoad = runAsync<void>([Placeholder] {
       if (auto Idx = loadIndex(IndexFile, /*UseDex=*/true))
         Placeholder->reset(std::move(Idx));
     });
     if (Sync)
       AsyncIndexLoad.wait();
   }
+#ifdef CLANGD_ENABLE_REMOTE
+  if (RemoteIndexAddress.empty() != ProjectRoot.empty()) {
+    llvm::errs() << "remote-index-address and project-path have to be "
+                    "specified at the same time.";
+    return 1;
+  }
+  if (!RemoteIndexAddress.empty()) {
+    if (IndexFile.empty()) {
+      log("Connecting to remote index at {0}", RemoteIndexAddress);
+      StaticIdx = remote::getClient(RemoteIndexAddress, ProjectRoot);
+      EnableBackgroundIndex = false;
+    } else {
+      elog("When enabling remote index, IndexFile should not be specified. "
+           "Only one can be used at time. Remote index will ignored.");
+    }
+  }
+#endif
   Opts.StaticIndex = StaticIdx.get();
   Opts.AsyncThreadsCount = WorkerThreadsCount;
   Opts.BuildRecoveryAST = RecoveryAST;
   Opts.PreserveRecoveryASTType = RecoveryASTType;
   Opts.FoldingRanges = FoldingRanges;
 
   clangd::CodeCompleteOptions CCOpts;
   CCOpts.IncludeIneligibleResults = IncludeIneligibleResults;