Re: [Chicken-users] Build Failure (maybe infinite recursion) on x86_64 Linux

[felix winkelmann]

On Mon, Mar 16, 2009 at 2:32 PM, Taylor Venable <address@hidden> wrote:
>
> Usually when it hangs, I end up sending it ^C when it's inside mark().
> So if I step out to C_reclaim() I can step through from line 2802 (or
> sometimes 2805; in runtime.c) to line 3016.  This I do in GDB using
> the "next" command.  When I hit line 3016 which is
>
>    C_longjmp(C_restart, 1);
>
> the program hangs again.  If I send it ^C again I'm back in that same
> region of code again inside C_reclaim.  This happens infinitely, as
> far as I can tell.

Right. The GC seems to loop.

>
> And tracing a bit further, it looks like C_library_toplevel() is
> continuously calling C_reclaim().  The code that looks like (library.c
> line 6616):
>
>    if(!C_demand(931)){
>    C_save(t1);
>    C_reclaim((void*)toplevel_trampoline,NULL);}
>
> keeps getting run; this is what's calling the C_reclaim() over and
> over again.  In fact, it seems that execution never makes it out of
> this loop; just these three lines ad infinitum.
>
> I found that the result of C_demand is based on C_stack_pointer and
> C_stack_limit.  I was unable to determine the former using GDB, but in
> this case C_stack_limit is always 0x7FFF83326C30.
>
> Hope this helps.  I've put my library.c on my website, since it seems
> to be generated code: http://real.metasyntax.net:2357/tmp/library.c.gz

Well done, Taylor. Chicken coalesces all allocations inside a single
generated C procedure and allocates it as one chunk. It seems here
that the stack is already too small to hold the data, even after a minor
GC was invoked. Can you reproduce the hang with larger settings for
"-:s..."? If you add "-:d", you should see messages like

[debug] stack resized to XXXX bytes

If you can't reproduce the hang with higher settings, change the makefile
(defaults.make or rules.make and pass "-:s<goodvalue>" to the "chicken-boot"
invocations and look how far it gets (BTW, what does "./chicken-boot -:d" show?)
Then we probably have a precompiled bootstrapping compiler with a too
low nursery setting, even though this used to work. It also may be something
completely different.


cheers,
felix