The tool hangs with an RDI::SOURCE window pop-up when running a "gets stdin" command from the Vivado Integrated Design Environment (IDE) Tcl Console.
As a result of the gets stdin command, the Vivado IDE waits for an input from the user on "stdin". Stdin is the command terminal from which the Vivado tool was launched (not the Tcl console). Typically, on a Windows platform, this terminal is hidden from the user.
To display it, do one of the following:
1) Call Vivado from a Vivado Tcl Shell with a start_gui command
2) In Windows, edit the "Target" field of your Vivado shortcut to the following: <install_path>\Vivado\2013.3\.\bin\vivado.bat
With the terminal open, inputs can be entered from the terminal.