Re: [sv-ec] covergroup sample method

Mike,

What's wrong with overriding using construction of specific covergroup 
instances?  For example:

  covergroup cg (ref int x);
    coverpoint x;
  endgroup
  ...
  cg cv_myLocalInt = new(myLocalInt);
  ...
  cg cv_someOtherInt = new(someOtherInt);

If you want to have the data for both of these merged together, the 
"merge_instances" option that we just approved -- Mantis 1897 -- could 
suffice.  The only difference from your proposal is that you have to 
keep around multiple instances of the covergroup and use the appropriate 
one for your desired "override".

-- David S


Michael Burns wrote:
>
> Hi folks,
>
> We've found a need in our methodology for an extension to the 
> covergroup sample method. Basically, we'd like to be able to call the 
> sample method on a covergroup with overrides so that we can specify 
> the data we want covered in the call, rather than just sampling 
> whatever the covergroup is connected to. This allows us to gather data 
> in local variables and dump it into the covergroup to be covered. This 
> is useful in assertion-based methodologies and perhaps elsewhere.
>
> There is a detailed proposal in Freescale, but I don't have it in hand 
> yet. I wanted to bring this up now so we have a chance to consider it 
> in Monday's meeting if possible.
>
> The general idea is that if you had a covergroup like this:
>
>   covergroup cg (ref int x);
>     coverpoint x;
>   endgroup
>
> you could explicitly specify data to be sampled like so:
>
>   cg.sample(.x(myLocalInt));
>
> where the args to sample() are overriding the formal arguments of the 
> covergroup.
>
> Has this need been addressed in some other way I'm not aware of? Does 
> this seem like a feasible approach?
>
> --Mike
>
>


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