[clangd] Add fallbackFlags initialization extension.

Summary:
This allows customizing the flags used when no compile database is
available. It addresses some uses of the old extraFlags extension.

Reviewers: ilya-biryukov

Subscribers: ioeric, MaskRay, jkorous, arphaman, kadircet, cfe-commits

Differential Revision: https://reviews.llvm.org/D53688

llvm-svn: 345973

1 files changed, 1 insertions, 0 deletions

diff --git a/clang-tools-extra/clangd/Protocol.cpp b/clang-tools-extra/clangd/Protocol.cpp
index 765c3429848..d8369f3dcc1 100644
--- a/clang-tools-extra/clangd/Protocol.cpp
+++ b/clang-tools-extra/clangd/Protocol.cpp
@@ -669,6 +669,7 @@ bool fromJSON(const json::Value &Params, InitializationOptions &Opts) {
 
   fromJSON(Params, Opts.ConfigSettings);
   O.map("compilationDatabasePath", Opts.compilationDatabasePath);
+  O.map("fallbackFlags", Opts.fallbackFlags);
   return true;
 }