[clangd] Propagate main context into ClangdServer

Summary:
Currently clangd initializes the ClangdServer lazily during
onInitialize request, and it results in propagation of caller's context rather
than the main context created ClangdLSPServer.

This patch changes the logic to store main context that created ClangdLSPServer
and pass it onto to ClangdServer and other objects like CDBs.

Reviewers: sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68978

llvm-svn: 374892

2 files changed, 22 insertions, 9 deletions

diff --git a/clang-tools-extra/clangd/ClangdLSPServer.cpp b/clang-tools-extra/clangd/ClangdLSPServer.cpp
index 4dc3412538a..3f825a6febd 100644
--- a/clang-tools-extra/clangd/ClangdLSPServer.cpp
+++ b/clang-tools-extra/clangd/ClangdLSPServer.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ClangdLSPServer.h"
+#include "Context.h"
 #include "Diagnostics.h"
 #include "DraftStore.h"
 #include "FormattedString.h"
@@ -465,10 +466,6 @@ void ClangdLSPServer::onInitialize(const InitializeParams &Params,
         break;
       }
   }
-  llvm::Optional<WithContextValue> WithOffsetEncoding;
-  if (NegotiatedOffsetEncoding)
-    WithOffsetEncoding.emplace(kCurrentOffsetEncoding,
-                               *NegotiatedOffsetEncoding);
 
   ClangdServerOpts.SemanticHighlighting =
       Params.capabilities.SemanticHighlighting;
@@ -490,8 +487,18 @@ void ClangdLSPServer::onInitialize(const InitializeParams &Params,
   }
   CDB.emplace(BaseCDB.get(), Params.initializationOptions.fallbackFlags,
               ClangdServerOpts.ResourceDir);
-  Server.emplace(*CDB, FSProvider, static_cast<DiagnosticsConsumer &>(*this),
-                 ClangdServerOpts);
+  {
+    // Switch caller's context with LSPServer's background context. Since we
+    // rather want to propagate information from LSPServer's context into the
+    // Server, CDB, etc.
+    WithContext MainContext(BackgroundContext.clone());
+    llvm::Optional<WithContextValue> WithOffsetEncoding;
+    if (NegotiatedOffsetEncoding)
+      WithOffsetEncoding.emplace(kCurrentOffsetEncoding,
+                                 *NegotiatedOffsetEncoding);
+    Server.emplace(*CDB, FSProvider, static_cast<DiagnosticsConsumer &>(*this),
+                   ClangdServerOpts);
+  }
   applyConfiguration(Params.initializationOptions.ConfigSettings);
 
   CCOpts.EnableSnippets = Params.capabilities.CompletionSnippets;
@@ -1184,9 +1191,9 @@ ClangdLSPServer::ClangdLSPServer(
     llvm::Optional<Path> CompileCommandsDir, bool UseDirBasedCDB,
     llvm::Optional<OffsetEncoding> ForcedOffsetEncoding,
     const ClangdServer::Options &Opts)
-    : Transp(Transp), MsgHandler(new MessageHandler(*this)),
-      FSProvider(FSProvider), CCOpts(CCOpts),
-      SupportedSymbolKinds(defaultSymbolKinds()),
+    : BackgroundContext(Context::current().clone()), Transp(Transp),
+      MsgHandler(new MessageHandler(*this)), FSProvider(FSProvider),
+      CCOpts(CCOpts), SupportedSymbolKinds(defaultSymbolKinds()),
       SupportedCompletionItemKinds(defaultCompletionItemKinds()),
       UseDirBasedCDB(UseDirBasedCDB),
       CompileCommandsDir(std::move(CompileCommandsDir)), ClangdServerOpts(Opts),
diff --git a/clang-tools-extra/clangd/ClangdLSPServer.h b/clang-tools-extra/clangd/ClangdLSPServer.h
index 5664efd388f..850da9813fa 100644
--- a/clang-tools-extra/clangd/ClangdLSPServer.h
+++ b/clang-tools-extra/clangd/ClangdLSPServer.h
@@ -10,6 +10,7 @@
 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_CLANGDLSPSERVER_H
 
 #include "ClangdServer.h"
+#include "Context.h"
 #include "DraftStore.h"
 #include "Features.inc"
 #include "FindSymbols.h"
@@ -131,6 +132,11 @@ private:
   void publishDiagnostics(const URIForFile &File,
                           std::vector<clangd::Diagnostic> Diagnostics);
 
+  // Since initialization of CDBs and ClangdServer is done lazily, the following
+  // context captures the one used while creating ClangdLSPServer and passes it
+  // to above mentioned object instances to make sure they share the same state.
+  Context BackgroundContext;
+
   /// Used to indicate that the 'shutdown' request was received from the
   /// Language Server client.
   bool ShutdownRequestReceived = false;