[lldb] Replace "127.0.0.1" with "localhost" in GDBRemoteCommunication.cpp

[jgorbe]

Summary

127.0.0.1 doesn't work in machines configured with IPv6-only networking.

[jgorbe]

Hm, I just realized I'm undoing https://reviews.llvm.org/D58883.

I'll withdraw this patch and upload it again once I'm sure I'm taking that into account.

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp

#else
         pipe_t write = socket_pipe.GetWritePipe();
         debugserver_args.AppendArgument(llvm::StringRef("--pipe"));
         debugserver_args.AppendArgument(llvm::to_string(write));
         launch_info.AppendCloseFileAction(socket_pipe.GetReadFileDescriptor());
 #endif
       } else {
         // No host and port given, so lets listen on our end and make the
         // debugserver connect to us..
-        error = StartListenThread("127.0.0.1", 0);
+        error = StartListenThread("localhost", 0);
         if (error.Fail()) {
           if (log)
             log->Printf("GDBRemoteCommunication::%s() unable to start listen "
                         "thread: %s",
                         __FUNCTION__, error.AsCString());
           return error;
         }
 
         ConnectionFileDescriptor *connection =
             (ConnectionFileDescriptor *)GetConnection();
         // Wait for 10 seconds to resolve the bound port
         uint16_t port_ = connection->GetListeningPort(std::chrono::seconds(10));
         if (port_ > 0) {
           char port_cstr[32];
-          snprintf(port_cstr, sizeof(port_cstr), "127.0.0.1:%i", port_);
+          snprintf(port_cstr, sizeof(port_cstr), "localhost:%i", port_);
           // Send the host and port down that debugserver and specify an option
           // so that it connects back to the port we are listening to in this
           // process
           debugserver_args.AppendArgument(llvm::StringRef("--reverse-connect"));
           debugserver_args.AppendArgument(llvm::StringRef(port_cstr));
           if (port)
             *port = port_;
         } else {
-          error.SetErrorString("failed to bind to port 0 on 127.0.0.1");
+          error.SetErrorString("failed to bind to port 0 on localhost");
           if (log)
             log->Printf("GDBRemoteCommunication::%s() failed: %s", __FUNCTION__,
                         error.AsCString());
           return error;
         }
       }
     }
     std::string env_debugserver_log_file =

 
 llvm::Error
 GDBRemoteCommunication::ConnectLocally(GDBRemoteCommunication &client,
                                        GDBRemoteCommunication &server) {
   const bool child_processes_inherit = false;
   const int backlog = 5;
   TCPSocket listen_socket(true, child_processes_inherit);
   if (llvm::Error error =
-          listen_socket.Listen("127.0.0.1:0", backlog).ToError())
+          listen_socket.Listen("localhost:0", backlog).ToError())
     return error;
 
   Socket *accept_socket;
   std::future<Status> accept_status = std::async(
       std::launch::async, [&] { return listen_socket.Accept(accept_socket); });
 
   llvm::SmallString<32> remote_addr;
   llvm::raw_svector_ostream(remote_addr)
-      << "connect://127.0.0.1:" << listen_socket.GetLocalPortNumber();
+      << "connect://localhost:" << listen_socket.GetLocalPortNumber();
 
   std::unique_ptr<ConnectionFileDescriptor> conn_up(
       new ConnectionFileDescriptor());
   Status status;
   if (conn_up->Connect(remote_addr, &status) != lldb::eConnectionStatusSuccess)
     return llvm::createStringError(llvm::inconvertibleErrorCode(),
                                    "Unable to connect: %s", status.AsCString());