I didn't realize Vivado was a Xilinx product. I haven't done much with Xilinx in some time. Diamond does include a Lattice synthesis tool, but I always use the Synopsis tool which is third party.
I seem to recall Xilinx stopped offering third party synthesis with the free tools some time back, but I seem to recall they had something different. But then many years ago a Xilinx person pointed out to me they spend more money on software development than they do software, or maybe they used more people or something like that. The point was they are a software company that collects revenue from selling the hardware that the software supports.