1 files changed, 37 insertions, 4 deletions
diff --git a/clang-tools-extra/clangd/GlobalCompilationDatabase.cpp b/clang-tools-extra/clangd/GlobalCompilationDatabase.cpp
index 95e7ce7ba69..a9161972893 100644
--- a/clang-tools-extra/clangd/GlobalCompilationDatabase.cpp
+++ b/clang-tools-extra/clangd/GlobalCompilationDatabase.cpp
@@ -8,12 +8,36 @@
 
 #include "GlobalCompilationDatabase.h"
 #include "Logger.h"
+#include "clang/Frontend/CompilerInvocation.h"
+#include "clang/Tooling/ArgumentsAdjusters.h"
 #include "clang/Tooling/CompilationDatabase.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 
 namespace clang {
 namespace clangd {
+namespace {
+
+void adjustArguments(tooling::CompileCommand &Cmd,
+                     llvm::StringRef ResourceDir) {
+  // Strip plugin related command line arguments. Clangd does
+  // not support plugins currently. Therefore it breaks if
+  // compiler tries to load plugins.
+  Cmd.CommandLine =
+      tooling::getStripPluginsAdjuster()(Cmd.CommandLine, Cmd.Filename);
+  // Inject the resource dir.
+  // FIXME: Don't overwrite it if it's already there.
+  if (!ResourceDir.empty())
+    Cmd.CommandLine.push_back(("-resource-dir=" + ResourceDir).str());
+}
+
+std::string getStandardResourceDir() {
+  static int Dummy; // Just an address in this process.
+  return CompilerInvocation::GetResourcesPath("clangd", (void *)&Dummy);
+}
+
+} // namespace
 
 static std::string getFallbackClangPath() {
   static int Dummy;
@@ -105,8 +129,11 @@ DirectoryBasedGlobalCompilationDatabase::getCDBForFile(
 }
 
 OverlayCDB::OverlayCDB(const GlobalCompilationDatabase *Base,
-                       std::vector<std::string> FallbackFlags)
-    : Base(Base), FallbackFlags(std::move(FallbackFlags)) {
+                       std::vector<std::string> FallbackFlags,
+                       llvm::Optional<std::string> ResourceDir)
+    : Base(Base), ResourceDir(ResourceDir ? std::move(*ResourceDir)
+                                          : getStandardResourceDir()),
+      FallbackFlags(std::move(FallbackFlags)) {
   if (Base)
     BaseChanged = Base->watch([this](const std::vector<std::string> Changes) {
       OnCommandChanged.broadcast(Changes);
@@ -115,16 +142,22 @@ OverlayCDB::OverlayCDB(const GlobalCompilationDatabase *Base,
 
 llvm::Optional<tooling::CompileCommand>
 OverlayCDB::getCompileCommand(PathRef File, ProjectInfo *Project) const {
+  llvm::Optional<tooling::CompileCommand> Cmd;
   {
     std::lock_guard<std::mutex> Lock(Mutex);
     auto It = Commands.find(File);
     if (It != Commands.end()) {
       if (Project)
         Project->SourceRoot = "";
-      return It->second;
+      Cmd = It->second;
     }
   }
-  return Base ? Base->getCompileCommand(File, Project) : None;
+  if (!Cmd && Base)
+    Cmd = Base->getCompileCommand(File, Project);
+  if (!Cmd)
+    return llvm::None;
+  adjustArguments(*Cmd, ResourceDir);
+  return Cmd;
 }
 
 tooling::CompileCommand OverlayCDB::getFallbackCommand(PathRef File) const {