Re: New features for GDB under Windows

[Daniel Jacobowitz <dan@codesourcery.com>]

On Mon, Jul 19, 2010 at 08:24:52AM +0200, Martin Rosenau wrote:
> However I thinks pipes will only work with Cygwin (Unix simulation on
> Windows), not with native Windows (required by Mingw etc.). I still
> could apply my patch to the current version of ser-pipe.c, if it is desired.

I use pipes with a mingw32 every day, and so do our customers.  So, I
know it works.  But if you know of a remaining problem, then we could
discuss your patch.

> >>> And the new feature:
> >>> - Remote debugging using special DLLs (this is faster than TCP/IP or
> >>> pipes and allows you to add new hardware targets - like JTAG adapters -
> >>> without re-compiling the entire GDB)
> > 
> > I don't know if this is a desired feature.  It runs into maintenance
> > and GPL compliance problems.
> > 
> The GPL compliance problems are an old problem running GPL programs
> under Windows. In some Internet forum I read the discussion if it is
> allowed to run GPL programs under Windows at all (it is (nearly)
> impossible to run any program under Windows without using Windows'
> closed-source DLLs!)
> Unfortunately there was no final conclusion about this problem.

That's a completely different problem.  There's language in the GPL to
describe exactly what is going on in that situation; it's called the
"system library exception", IIRC.

> What I do not understand is the term "maintenance problems". Do you think
> - about compatibility problems (a DLL for 7.x could not run under 8.x)

This is the primary issue.  If we allow plugins, we need to define,
validate, maintain, and preserve an interface for them.  We don't want
to do that.  At least, I don't.

I've never seen a GDB that used external DLLs for target access and
didn't violate our understanding of the GPL (and I've seen at least
two that I can recall).

-- 
Daniel Jacobowitz
CodeSourcery