Is nexti confused by pushq?

David Griffiths dgriffiths@undo.io
Tue Feb 26 14:42:00 GMT 2019


Thanks Dmitry, I will avoid nexti. It's pretty weird stepping through JITed
code anyway, sometimes even a breakpoint/continue is not enough because it
dives off into deopt functions and re-emerges in the interpreter!

On Tue, 26 Feb 2019 at 14:19, Dmitry Samersoff <dms@samersoff.net> wrote:

> David,
>
> On 26.02.2019 14:50, David Griffiths wrote:
> > Ok, so in my case this is generated code with no debug info (Java JIT
> > generated) so does that mean I shouldn't attempt to use nexti? (I've got
> > other issues which probably preclude using nexti anyway but just curious)
>
> On my experience with Java JIT (C2) produced code, it's better to avoid
> using nexti.
>
> If you do it programmatically, you can try to mimic nexti behavior in
> some cases by analyzing instructions ahead and setting breakpoint where
> appropriate.
>
> -Dmitry
>
> >
> > Cheers,
> >
> > David
> >
> > On Tue, 26 Feb 2019 at 10:12, Jan Kratochvil <jan.kratochvil@redhat.com>
> > wrote:
> >
> >> On Tue, 26 Feb 2019 08:32:37 +0100, Andrew Burgess wrote:
> >>> Of course, this doesn't solve the problem for you, but at least you
> >>> know what's going wrong now :)
> >>
> >> To make it clear the debuggee has wrong/insufficient debug info, its
> >> .eh_frame/.debug_frame there should annotate the push (and pop)
> >> instructions.
> >>
> >>
> >> Jan
> >>
> >
> >
>


-- 

David Griffiths, Senior Software Engineer

Undo <https://undo.io> | Resolve even the most challenging software defects
with software flight recorder technology

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