[lldb-dev] JIT debugging and Windows

Wed Jan 1 14:03:50 PST 2014

On Wednesday, January 01, 2014 04:50:37 PM Keno Fischer wrote:
> Actually, never mind, I am getting backtraces (Woot!!). Still not getting
> line numbers though.

That's really exciting!

--Tim

> 
> 
> On Wed, Jan 1, 2014 at 3:39 PM, Keno Fischer
> 
> <kfischer at college.harvard.edu>wrote:
> > I'm currently in holiday mode as well. A couple of things that I didn't
> > get to that need to be resolved (these are pretty general questions on
> > lldb
> > itself, so I'd appreciate input from anybody on this list):
> > 
> > - I'm using a regular rather than an internal breakpoint, because the
> > latter does not get updated when shared libraries are loaded (Is this
> > intended? Is there a recommended workaround?)
> > 
> > - I'm not seeing the function in backtraces even though I can set
> > breakpoints. Is there anything else that needs to be done/ Do the
> > backtraces use different information that is perhaps not relocated
> > properly? If so, how can I check?
> > 
> > - I'm also not seeing line numbers, etc. Probably related to the second
> > point.
> > 
> > - Keno
> > 
> > 
> > On Tue, Dec 31, 2013 at 10:16 AM, Andrew MacPherson <andrew.macp at gmail.com
> > 
> > > wrote:
> >> This looks great. I'm still in holiday mode but will tackle any
> >> outstanding ELF-related work when I'm back on Thursday, feel free to ping
> >> me or the list again if you get any further. Thanks for pushing on this!
> >> 
> >> Cheers,
> >> Andrew
> >> 
> >> 
> >> On Sun, Dec 29, 2013 at 6:29 PM, Keno Fischer <
> >> 
> >> kfischer at college.harvard.edu> wrote:
> >>> I've gotten pretty far,
> >>> Code is here: https://github.com/loladiro/lldb
> >>> It's interacting correctly with the debug interface and I've got it
> >>> loading the object file from memory correctly for
> >>> MachO/DWARF (working on ELF right now). Currently not much use as it
> >>> doesn't seem to be looking at the
> >>> debug information that were just added (I can see them via `image dump
> >>> sections` and I can set breakpoints
> >>> correctly though, so that's a plus). For DWARF, there's a few changes
> >>> for upstream LLVM needed. I'll put them
> >>> up if anybody's interested, otherwise, I'll just keep chugging along and
> >>> wait until I have more complete patch.
> >>> 
> >>> - Keno
> >>> 
> >>> 
> >>> On Sat, Dec 28, 2013 at 1:07 PM, Andrew MacPherson <
> >>> 
> >>> andrew.macp at gmail.com> wrote:
> >>>> Hi Keno,
> >>>> 
> >>>> I noticed the same thing and agree that the JIT loader doesn't
> >>>> perfectly fit as a DynamicLoader, the suggestion from a couple of years
> >>>> back on the list was to make the Process -> DynamicLoader relationship
> >>>> 1:n
> >>>> but I prefer your suggestion of adding a new plugin type (JITLoader).
> >>>> Right
> >>>> now there would only be one JITLoader type for the GDB interface.
> >>>> 
> >>>> The patch could probably be fixed up as-is as a first step (leaving the
> >>>> JIT loading bits as a growth on the DynamicLoaderPOSIXDYLD) and we
> >>>> could
> >>>> move it out into its own plugin type once that's working. I should have
> >>>> time this coming week to get this working but if you'll also have time
> >>>> then
> >>>> I'm happy to leave it with you.
> >>>> 
> >>>> Cheers,
> >>>> Andrew
> >>>> 
> >>>> 
> >>>> On Sat, Dec 28, 2013 at 9:37 AM, Keno Fischer <
> >>>> 
> >>>> kfischer at college.harvard.edu> wrote:
> >>>>> I've started looking into this and it's actually not that difficult to
> >>>>> do (the JIT part at least). I think the most difficult thing is
> >>>>> figuring out where to put the functionality. The way I see it, the JIT
> >>>>> interface is almost a DynamicLoader, with the difference
> >>>>> that asking it about things like whether or not loading a dynamic
> >>>>> library is safe doesn't make much sense. Another problem
> >>>>> is that currently there's a 1:1 relationship between Processes and
> >>>>> DynamicLoaders. Perhaps a new class of Plugins
> >>>>> (JITLoader?) could be added with a 1:n relationship to processes. Some
> >>>>> of the interface (I'm thinking
> >>>>> 
> >>>>>  DidLaunch,DidAttach,Get/SetStopWhenImagesChange) could be pulled out
> >>>>> 
> >>>>> into an abstract base class. Does that make
> >>>>> sense. I'd be happy to implement this once we decide on the design.
> >>>>> 
> >>>>> Keno
> >>>>> 
> >>>>> 
> >>>>> On Wed, Dec 25, 2013 at 10:30 AM, Andrew MacPherson <
> >>>>> 
> >>>>> andrew.macp at gmail.com> wrote:
> >>>>>> Looks great, thanks Keno. I'll look into this next week and keep you
> >>>>>> posted.
> >>>>>> 
> >>>>>> Cheers,
> >>>>>> Andrew
> >>>>>> 
> >>>>>> 
> >>>>>> On Tue, Dec 24, 2013 at 1:19 PM, Keno Fischer <
> >>>>>> 
> >>>>>> kfischer at college.harvard.edu> wrote:
> >>>>>>> I have this (as I said, I haven't tried it). It seems to be a
> >>>>>>> different patch.
> >>>>>>> 
> >>>>>>> 
> >>>>>>> On Tue, Dec 24, 2013 at 11:17 AM, Andrew MacPherson <
> >>>>>>> 
> >>>>>>> andrew.macp at gmail.com> wrote:
> >>>>>>>> Hi Keno,
> >>>>>>>> 
> >>>>>>>> I found this old patch that hooks into the GDB JIT registration
> >>>>>>>> mechanism which we were planning to use as a starting point:
> >>>>>>>> 
> >>>>>>>> 
> >>>>>>>> http://lists.cs.uiuc.edu/pipermail/lldb-dev/2010-December/000314.ht
> >>>>>>>> ml
> >>>>>>>> 
> >>>>>>>> If you have anything else we'd love to take a look!
> >>>>>>>> 
> >>>>>>>> Cheers,
> >>>>>>>> Andrew
> >>>>>>>> 
> >>>>>>>> 
> >>>>>>>> On Tue, Dec 24, 2013 at 8:34 AM, Keno Fischer <
> >>>>>>>> 
> >>>>>>>> kfischer at college.harvard.edu> wrote:
> >>>>>>>>> Hi Andrew,
> >>>>>>>>> 
> >>>>>>>>> I'm also one of the Julia core developers and the guy currently
> >>>>>>>>> working on
> >>>>>>>>> debugging support. I was given a patch to add MCJIT debugging
> >>>>>>>>> support
> >>>>>>>>> to LLDB with the disclaimer that it probably doesn't work. I
> >>>>>>>>> haven't tried it
> >>>>>>>>> yet, so I can't say how close it is, but it's probably at least a
> >>>>>>>>> starting point.
> >>>>>>>>> 
> >>>>>>>>> I'd be happy to coordinate any efforts.
> >>>>>>>>> 
> >>>>>>>>> - Keno
> >>>>>>>>> 
> >>>>>>>>> _______________________________________________
> >>>>>>>>> lldb-dev mailing list
> >>>>>>>>> lldb-dev at cs.uiuc.edu
> >>>>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev