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From "Ilya Berezhniuk" <ilya.berezhn...@gmail.com>
Subject Re: Thoughts...
Date Tue, 16 Oct 2007 14:23:19 GMT
Vasily,

Thank you for explanation and answers.
Now the approach with external debugging looks much better for me.


2007/10/16, Vasily Levchenko <vasily.v.levchenko@gmail.com>:
> sds
>
> On 10/14/07, Ilya Berezhniuk <ilya.berezhniuk@gmail.com> wrote:
> >
> > Hi all,
> >
> > Let me speak to NCAI debugging approach.
> >
> > 1) JVMTI is implemented using self-process debugging; it will never be
> > implemented by another way, I guess.
>
>
> Sounds reasonable. But let's look closer, JVMTI is a way of debugging of
> managed code and that is enough isolation, VM border doesn't provide
> isolation for native debugging, that is a reason why native debuggers except
> kernel debuggers are isolated with process borders.
>
>
> So NCAI merely extends JVMTI
> > approach to native code debugging.
>
>
> With NCAI we  try to apply the same mechanisms for unmanaged code, like we
> do it for managed and that I think is not so good. For full function
> debugger (long-term) we will have to make extension interface but it will
> work in debugger address space like thread_db or any other interface
> provided by OS.
>
> Using external debugger for debugging native code will lead to using 2
> > different debuggers simultaneously - it can lead to conflicts between
> > the debuggers.
> >
> > 2) Any debugger should be aware about some VM internals when debugging
> > JNI code.
>
>
> I absolutely agree with you, opposite solutions will be led to less
> adoption, instead I prefer debugger interfaces for VM-specific modules, like
> it was already done for OS specific modules.
>
>
> So external debugger would use some callbacks functions in
> > VM.
>
>
> External debugger can call debugee functions that could be helper function
> in JVMTI agent.
>
> But those callbacks would be not for debugging itself, but for
> > exposing some raw info about VM internals.
>
>
> It not necessary  to get internal VM information for JVMTI based solution ;)
> JVMTI interface provides enough information to manage java world from
> external debugger the difference between JDI/JDWP/JVMTI is in method of
> sending command, debugger use ptrace for writing data directly into the
> debugee address space.
>
> Quite the opposite, NCAI is
> > well defined debug interface which provides processed data in a form
> > like JVMTI does.
> >
> >
> > 2007/10/12, Pavel Pervov <pmcfirst@gmail.com>:
> > > +1 for accepting it now. NCAI is a good extension to mechanisms
> > naturally
> > > provided by Java debugger.
> > >
> > > On 10/12/07, Mikhail Loenko <mloenko@gmail.com> wrote:
> > > >
> > > > We now have all requisite paperwork in place for
> > > > http://issues.apache.org/jira/browse/HARMONY-4689, so let's vote to
> > > > accept:
> > > >
> > > > [ ] +1 Accept this contribution
> > > > [ ] -1 Reject because...
> > > >
> > > > As usual, 3 days unless someone complains they need more time.
> > > >
> > >
> > >
> > >
> > > --
> > > Pavel Pervov,
> > > Intel Enterprise Solutions Software Division
> > >
> >
> >
> > --
> >
> > Ilya
> >
>
>
>
> --
> --vvl
>


-- 

Ilya

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