[clangd] Optionally add reflection for clangd-index-server

This was originally landed without the optional part and reverted later:

8080ea4c4b

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D98404

clang-tools-extra/clangd/CMakeLists.txt

@@ -19,6 +19,7 @@ option(CLANGD_MALLOC_TRIM "Call malloc_trim(3) periodically in Clangd. (only tak
 llvm_canonicalize_cmake_booleans(
   CLANGD_BUILD_XPC
   CLANGD_ENABLE_REMOTE
+  ENABLE_GRPC_REFLECTION
   CLANGD_MALLOC_TRIM
   LLVM_ENABLE_ZLIB
 )

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

@@ -1,3 +1,4 @@
 #define CLANGD_BUILD_XPC @CLANGD_BUILD_XPC@
 #define CLANGD_ENABLE_REMOTE @CLANGD_ENABLE_REMOTE@
+#define ENABLE_GRPC_REFLECTION @ENABLE_GRPC_REFLECTION@
 #define CLANGD_MALLOC_TRIM @CLANGD_MALLOC_TRIM@

clang-tools-extra/clangd/index/remote/server/CMakeLists.txt

@@ -17,4 +17,6 @@ target_link_libraries(clangd-index-server
   RemoteIndexProto
   RemoteIndexServiceProto
   clangdRemoteMarshalling
+
+  ${REFLECTION_LIBRARY}
   )

clang-tools-extra/clangd/index/remote/server/Server.cpp

@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "Features.inc"
 #include "Index.pb.h"
 #include "Service.grpc.pb.h"
 #include "index/Index.h"
@@ -35,6 +36,10 @@
 #include <memory>
 #include <thread>
 
+#if ENABLE_GRPC_REFLECTION
+#include <grpc++/ext/proto_server_reflection_plugin.h>
+#endif
+
 namespace clang {
 namespace clangd {
 namespace remote {
@@ -313,6 +318,9 @@ void runServerAndWait(clangd::SymbolIndex &Index, llvm::StringRef ServerAddress,
   RemoteIndexServer Service(Index, IndexRoot);
 
   grpc::EnableDefaultHealthCheckService(true);
+#if ENABLE_GRPC_REFLECTION
+  grpc::reflection::InitProtoReflectionServerBuilderPlugin();
+#endif
   grpc::ServerBuilder Builder;
   Builder.AddListeningPort(ServerAddress.str(),
                            grpc::InsecureServerCredentials());

llvm/cmake/modules/FindGRPC.cmake

@@ -1,3 +1,5 @@
+option(ENABLE_GRPC_REFLECTION "Link clangd-index-server to gRPC Reflection library" OFF)
+
 # FIXME(kirillbobyrev): Check if gRPC and Protobuf headers can be included at
 # configure time.
 find_package(Threads REQUIRED)
@@ -22,6 +24,10 @@ if (GRPC_INSTALL_PATH)
   add_library(protobuf ALIAS protobuf::libprotobuf)
   set_target_properties(gRPC::grpc++ PROPERTIES IMPORTED_GLOBAL TRUE)
   add_library(grpc++ ALIAS gRPC::grpc++)
+  if (ENABLE_GRPC_REFLECTION)
+    set_target_properties(gRPC::grpc++_reflection PROPERTIES IMPORTED_GLOBAL TRUE)
+    add_library(grpc++_reflection ALIAS gRPC::grpc++_reflection)
+  endif()
 
   set(GRPC_CPP_PLUGIN $<TARGET_FILE:gRPC::grpc_cpp_plugin>)
   set(PROTOC ${Protobuf_PROTOC_EXECUTABLE})
@@ -71,12 +77,21 @@ else()
   add_library(grpc++ UNKNOWN IMPORTED GLOBAL)
   message(STATUS "Using grpc++: " ${GRPC_LIBRARY})
   set_target_properties(grpc++ PROPERTIES IMPORTED_LOCATION ${GRPC_LIBRARY})
+  if (ENABLE_GRPC_REFLECTION)
+    find_library(GRPC_REFLECTION_LIBRARY grpc++_reflection $GRPC_OPTS REQUIRED)
+    add_library(grpc++_reflection UNKNOWN IMPORTED GLOBAL)
+    set_target_properties(grpc++_reflection PROPERTIES IMPORTED_LOCATION ${GRPC_REFLECTION_LIBRARY})
+  endif()
   find_library(PROTOBUF_LIBRARY protobuf $PROTOBUF_OPTS REQUIRED)
   message(STATUS "Using protobuf: " ${PROTOBUF_LIBRARY})
   add_library(protobuf UNKNOWN IMPORTED GLOBAL)
   set_target_properties(protobuf PROPERTIES IMPORTED_LOCATION ${PROTOBUF_LIBRARY})
 endif()
 
+if (ENABLE_GRPC_REFLECTION)
+  set(REFLECTION_LIBRARY grpc++_reflection)
+endif()
+
 # Proto headers are generated in ${CMAKE_CURRENT_BINARY_DIR}.
 # Libraries that use these headers should adjust the include path.
 # If the "GRPC" argument is given, services are also generated.