It's been like this for over 20 years. I was trying to persuade people on comp.arch.fpga 20 years ago that we should band together and produce some open tools

It's been like this for over 20 years. I was trying to persuade people on comp.arch.fpga 20 years ago that we should band together and produce some open tools for Xilinx, and I was eager to do it myself. People warned me that Xilinx were legally very aggressive and that I could lose everything I owned. Nobody wanted to get involved then. At one point an academic paper about alternative programming techniques on Xilinx devices withdrew some of their work, out of legal concerns. So I kept out of it too. In fact, I quit working with FPGAs for a long time (it had been my main job, developing and using hardware compilers at a higher level than VHDL/Verilog), so that my previous use of Xilinx and Altera software might become a distant memory and I wouldn't feel that the licensing restrictions accompanying their old software would constrain reverse engineering on a new generation. I was intending to eventually reverse engineer some of the devices from first principles without using their software. We know that can be done to some extent just by programming bitstreams. Timing and power models are more difficult to reverse engineer, but not impossible and I had some measurement ideas, and I had in mind to additionally etch and photograph the chips as well, or perhaps use focused X-ray tomography. But that never happened; life happened instead. Times have changed. The FPGA patents from that era have expired. You can build a decent device without infringing, in principle. There's a rapidly growing movement in open source hardware on FPGAs and even ASICs. And people have been reversing Xilinx among others, more confidently than the people of 20 years ago were willing to. For today I have two words: QuickLogic and OpenFPGA. QuickLogic devices may be small compared with the high end, but they are explicitly supporting open source toolchains, better than Lattice's passive tolerance. This is a breath of fresh air, and I hope they are successful. OpenFPGA is actual open source FPGAs.