[Vm-dev] re: debugging the garbage collector

[Noah Evans]

Craig, which version of Cog are you using? I'm using the tip of the
gitorious tree. There are a few discrepancies with the function
signatures of the VM structure (a few places where char* are void* and
vice versa). Also the functions provided by interp.c seem to
correspond to

#if VM_PROXY_MINOR > 7

in sqVirtualMachine.c and no further.

Noah


On Fri, Feb 15, 2013 at 11:07 AM, Craig Latta <craig at netjam.org> wrote:
>
>
> Hi--
>
>      Noah writes:
>
>> Can anyone give me any pointers to documentation or personal
>> experience regarding debugging the object memory and GC?
>
>      Glad you're in the thick of it! :)
>
>      The only debugging like that I've had to do was prompted by trouble
> in the object memory, not the virtual machine, so I've been able to get
> by with evaluating Interpreter>>allAccessibleObjectsOkay and the like,
> at the Smalltalk level at strategic moments. Things like
> ObjectMemory>>validateRoots, which can be translated to C and enabled
> (by turning on DoAssertionChecks) may help in C-debugger-land.
>
>      I was lucky in past host platform bringups that the GC worked
> without modification, from those who came before me on other platforms.
> What this usually means is that the new platform's C environment is
> sufficiently similar to the other ones. I strongly suspect this will
> come down to some C compiler flag or preprocessor whim (hence projects
> which try to get rid of the C compilation part from bootstrapping
> completely).
>
>      David writes:
>
>> I'm assuming that your VM is derived from a relatively recent
>> interpreter VM code base, maybe Craig can confirm?
>
>      The current release of Spoon is 3 beta 3 (23 October 2012),
> available at:
>
>      http://netjam.org/spoon/releases/current
>
>      It includes a Squeak 4.2 object memory (4 February 2011) with
> VMMaker dtl.237 (23 May 2011) installed, and the Spoon VM changes
> applied to that, and with remote browsing support installed. It runs on
> the VM it generates, which is the only one supplied in the release (Mac
> OS, Linux and win32).
>
>
>      thanks again,
>
> -C
>
> --
> Craig Latta
> www.netjam.org/resume
> +31 6 2757 7177 (SMS ok)
> + 1 415  287 3547 (no SMS)
>