[clangd] Allow specifying -resource-dir

Summary: This patch allows clangd to specify its -resource-dir.

Reviewers: bkramer, klimek

Reviewed By: bkramer

Subscribers: cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D35617

llvm-svn: 308486
diff --git a/clang-tools-extra/clangd/tool/ClangdMain.cpp b/clang-tools-extra/clangd/tool/ClangdMain.cpp
index d67f75b..199c298 100644
--- a/clang-tools-extra/clangd/tool/ClangdMain.cpp
+++ b/clang-tools-extra/clangd/tool/ClangdMain.cpp
@@ -25,6 +25,11 @@
                      llvm::cl::desc("parse on main thread"),
                      llvm::cl::init(false), llvm::cl::Hidden);
 
+static llvm::cl::opt<std::string>
+    ResourceDir("resource-dir",
+                llvm::cl::desc("directory for system clang headers"),
+                llvm::cl::init(""), llvm::cl::Hidden);
+
 int main(int argc, char *argv[]) {
   llvm::cl::ParseCommandLineOptions(argc, argv, "clangd");
 
@@ -35,6 +40,9 @@
   // Change stdin to binary to not lose \r\n on windows.
   llvm::sys::ChangeStdinToBinary();
 
-  ClangdLSPServer LSPServer(Out, RunSynchronously);
+  llvm::Optional<StringRef> ResourceDirRef = None;
+  if (!ResourceDir.empty())
+    ResourceDirRef = ResourceDir;
+  ClangdLSPServer LSPServer(Out, RunSynchronously, ResourceDirRef);
   LSPServer.run(std::cin);
 }