Personally I'd rather have effort spent on a high quality emacs-mode for RTL development. VHDL mode is good, Verilog mode is good, but there is a _huge_ opportunity to improve the current situation. I'd also like to see a more "standardized" makefile based build system so that not every developer has to reinvent that particular wheel. Especially since the available parts (command line tools) are sometimes cumbersome to fit into the wheel (makefile).
Opencores would seem like an ideal place for development of something like this. However, one problem that might bite open source efforts in this area is patents. While software patents might not be legal in at least some parts of the world, hardware patents are. So the legal status of a hypothetical parameterizable hardware library would be less certain than a software library... Personally I'm curious whether distributing the RTL source code for lets say an FFT core which is implemented using the "Foo bar method" infringes upon JBN's patent on a hardware implemention of the "Foo bar method".
As an aside, Opencores actually had a "socbuilder" project, unfortunately no activity has taken place there for 3 years or so.
Actually, I think an open source FPGA floorplanning tool could be done. I've been thinking about it myself at some time and it wouldn't require that much knowledge of the device. It might even be possible to do a placer as open source (I've been toying with the idea of writing my own placer algorithm as a hobby project, just to see how difficult it is to get decent results. I certainly wouldn't realistically expect to beat the Xilinx placer though :))
Making a good quality router is probably much more difficult. (You could do probably do a bad router by using a subset of the available wires and not worry about the timing constraints though.) A good quality router would not only need access to all routing possibilities in some way but also the timing properties of the paths.
I could also point out that there actually is source code available on the net for a place and routing tool (VPR). But the license is not open source last time I checked
Hear hear!
All in all, lots of good thoughts in Ben's posting I think.
Some extra bonus thoughts from me: the open source community probably don't gain any good will by demanding an arm and a leg from Altera and Xilinx without showing that we can add significant value to their bottom line.
For example, if we show that we can build a high quality synthesizer frontend that has about the same performance as XST, they might seriously consider contributing to that effort, perhaps even replacing their own tool with the open source tool. But right now the only open source synthesizing tool I'm aware of (Icarus) has a much too small user community to make that happen.
/Andreas