Re: [Valgrind-developers] Experimental Valgrind coverage tool

[Nicholas N. <nj...@cs...>]

On Mon, 4 Feb 2008, Benjamin Meyer wrote:

>> I've written an experimental Valgrind coverage tool, called VCov.
>
> Does it do anything callgrind can't do?  Several other people
> (including me) have written similar tools only to realize after the
> fact that callgrind files are good enough and can even include jumps
> if you pass --collect-jumps=yes to the args.  By letting callgrind
> collect the data you can spend your time creating the value add of
> the tool, source integration, report generating etc, without worrying
> about any of the valgrind stuff.

On the tool (data gathering) side:
- It's faster than Callgrind.
- It aggregates data from multiple executions into a single output file,
   which makes it much easier to use.
- It records info about lines of code that are executable but were not
   executed.  This allows the post-processing tool to be simpler, eg.
   no language-specific parsing is necessary.
- The code is much simpler.  Callgrind is almost 12,000 lines of code.
   VCov is 750.  Separating them also makes it easier to change VCov if
   it needs capabilities that don't fit into Callgrind.

> You e-mailed me about the valgrind-tools that I wrote (http://
> benjamin-meyer.blogspot.com/2007/12/valgrind-callgrind-tools-part-3-
> code.html) .  Was there any particular reason why it wasn't good
> enough, I know it isn't perfect, but were you able to get it working
> at least?

I haven't tried it.

I had VCov in its current state before you wrote about your tool, and I 
promised someone that I would make VCov available in a way that lets him use 
it.  It is on a branch, so it won't necessarily end up in the distribution.

Nick