Show information in log file under Vivado 2015.1?

Question

In XST and in Vivado through 2014.4 I used something like:
  assert false report "FFV_D sees KEEP_HIERARCHY: " & Value(KeepHierarchy) severity NOTE;
to figure out what was going on in Vivado during synthesis.
With Vivado 2015.1, instead of the report from the constant condition assert statement, I now get:
  WARNING: [Synth 8-312] ignoring unsynthesizable construct: assertion statement [h:/Eng/MVhdl/Src/Base/MReg.vhd:1731]
Is there some other means to write report information into the Vivado log during synthesis?
I most use this so that I can verify the state of generics within entities, but I use the mechanism all the time for debugging synthesis.
Ian Lewis
www.mstarlabs.com
 

Answer 1

Hello Brian,
I certainly hope that Vivado has some means of reporting from within HDL.
I agree that removing static condition assert support is a horrible idea, especially since the Vivado synthesis log does not provide even as good information as XST did: http://forums.xilinx.com/t5/Synthesis/Requests-for-Vivado-synthesis-log-changes/td-p/590481 . Or, at least, I cannot interpret the Vivado synthesis log at all well.
I have not yet read enough copies of the log for different conditions to be sure that it is fundamentally unclear, but more and more it looks to me like it just does not include enough information for anyone to know exactly what Vivado has done with respect to generic bindings for specific instances. I know it does not include enough information to even have a clue what it has done with respect to applying attributes.
In any case, even if Vivado synthesis provided a perfect and complete implementation of VHDL, and its log contained every bit of information one could imagine wanting to show how it binds entities and generics, it is essential to be able to see what the compiler is really doing at the level of one's own code: you can read the LRM until you are blue, but at some point you need to see what is really happening in a specific instance of code.
And, there is good reason to report into the log some facts about how one configured an entity at a higher level than the individual generics so you can quickly see that you did what you intended to do.
I could live with changing our asserts to something else, but some means to report into the log is important. It is not just some whim.
Ian Lewis
www.mstarlabs.com