Ruby-VPI - VCS Core Dump iterating for DefParams

Suraj Kurapati sunaku at
Wed Oct 21 00:36:37 EDT 2009

On Tue, Oct 20, 2009 at 3:56 PM, Josh Gold <joshg at> wrote:
> Every interface in the vpiModule can be accessed correctly
> without any issues.

Glad to hear this.

> The only issue occurs when trying to read the
> vpiDepParam objects.  The error is a core dump in VCS.  This issue seems to
> be regardless to version as VCS fails on both 2006.06-sp1 and 2009.06.  I am
> using ruby-vpi version 21.1.0 as well.
> The core dump occures on the following code section:
> defparamIterater = vpi_iterate(vpiDefParam, designHandle)
> while(defParamHandle = vpi_scan(defparamIterater))
>   p defParamHandle
> end
> The error that VCS reports before the stack traces are dumped is:
> Internal error in tool's source file "../vir/" line 311.
> Please send these messages to vcs_support at

Try setting the CFLAGS_EXTRA or the CFLAGS environment variable before
installing Ruby-VPI and you should be able to inspect the core dump
with GDB:

$ export CFLAGS_EXTRA='-g -DDEBUG'
$ gem install ruby-vpi # will reinstall it
$ rake vcs ... # run your test
(core dump)
$ gdb core `which vcs`
(gdb) bt full  # print stack trace

> Again, this only occurs when trying to view design defparams.  Has anyone
> seen this error before?  I was hoping this was something someone has seen
> before because its hard to imagine that there is a global problem trying to
> view defparams.

I haven't tried doing this before and the issue hasn't been raised on
this mailing list so far.

If you can provide a sample Verilog file that enables the Ruby code
you posted, I can run it against other simulators for comparison.

Otherwise, please wait for a few days while I regain my strength.  I'm
overloaded at work and don't have much energy for tinkering at the


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