[gambit-list] Gambit debug levels Re: What's the..

Mikael mikael.rcv at gmail.com
Tue Sep 17 09:16:06 EDT 2013

Great question. To look into what debug levels could be made of, for
clarity let's first look into what debug functionality is implemented i.e.
is enabled on --enable-debug , so now question back to you:

Is the following list complete, or is there anything to add to or to
correct about it?

--enable-debug brings:
 1) Debug symbols at the level of C by passing -g to C compiler, making it
include C-level debug symbols
 2) Debug symbols at the level of Scheme, by Gambit including in the GVM/C
code all define names and their code locations for display in code traces
like ,be
 3) Generation of the "console" file
 4) GC heap consistency checks ability, only invoked if enabled on runtime
 5) GC: Generation of the movable_pair_objs and movable_subtyped_objs
variables introspectable via GDB (GATHER_STATS)

--enable-debug does *not* bring:
 6) Individual tracing of malloc&free:s beyond ___base_mod.alloc_mem_calls
!= ___base_mod.free_mem_calls check on exit (___DEBUG_ALLOC_MEM_TRACE)
 7) GC debug output (___DEBUG_GARBAGE_COLLECT)
 8) TTY state dumps (___DEBUG_TTY)
 9) ___DEBUG_STACK_LIMIT and ___DEBUG_HEAP_LIMIT (not sure how it works out)
 10) ___DEBUG_HOST_CHANGES (no clue what this is, seems insignificant
( * And then to make this discussion complete, regarding all the
___DEBUG_SETTINGS_* defines: These are not influenced at all by
--enable-debug but are compiled in always and describe settings only
enabled on runtime given command line arguments as parsed in main.c , and
they're all unused in the code except for for enabling the GC consistency


2013/9/17 Marc Feeley <feeley at iro.umontreal.ca>

> On 2013-09-07, at 10:12 AM, Mikael <mikael.rcv at gmail.com> wrote:
> > Dear Marc,
> >
> > What is the best practice for configuring Gambit to maintain maximum
> debug settings switched on but no output of a "console" file?
> >
> >
> > (
> > By maximum debug settings, I mean export of debug symbols, so this could
> be done by CFLAGS="-g" CXXFLAGS="-g" ./configure , and optionally "-o0" or
> "-o1" on that -
> >
> > And.. is there any more debug level functionality in Gambit, for
> instance does --enable-debug switch on any debug functionality beyond -g
> and "console" file output?
> >
> > The console file is not needed as it's of such a lowlevel nature, and it
> easily grows infinitely as in >>100GB.
> >
> > Also, switching off while maintaining --enable-debug requires such large
> amounts of code changes, that I'd presume --enable-debug actually was
> intended first and foremost as an enabler of "console" file output?
> > )
> >
> > Thanks!
> > Mikael
> >
> I'll turn your question back into a question to you... what would be
> appropriate levels of debugging?  What do you need specifically?  I can add
> configure flags and runtime options to control the debugging level.
> Marc
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