Re: Build Error in master

[Noah Lavine <noah.b.lavine@gmail.com>]

Got it! And unfortunately, it's a GC error. Here's what happens:

symbols is an SCM object defined in symbols.c. It points to an
scm_cell_t which has two elements: a type tag, and a pointer to an
scm_weak_set_t. That scm_cell_t is at 0x10101cff0.

However, that scm_cell_t is garbage collected in the scm_cons at
symbols.c:250. The reason it gets filled with SCM_EOL is that the cons
is scm_cons (SCM_BOOL_F, SCM_EOL). So I expect that the scm_cell_t is
garbage collected and then immediately reclaimed to be the pair, which
would result in its second cell being filled with SCM_EOL, which would
explain why we later extract SCM_EOL from it.

As a test, I changed the variable 'symbols' in symbols.c to be
non-static. That didn't fix it, but then again, I don't really know
how GC works yet.

I can read the libgc documentation and try to figure this out, but can
anyone point me to what I should be looking for?

Thanks,
Noah

On Wed, Feb 1, 2012 at 4:01 AM, Andy Wingo <wingo@pobox.com> wrote:
> On Wed 01 Feb 2012 03:12, Noah Lavine <noah.b.lavine@gmail.com> writes:
>
>> In the failing call,
>>   the SCM 'symbols' is 0x10101cff0, but the failing set is at 0x304,
>> which has not been allocated.
>
> 0x304 is one of the iflags, SCM_EOL I think.
>
> So, I know it might not have anything to do with it, but can you verify
> that your guile includes patch 0aed71aa51e89e714de2392c2a5f44694dca77ea
> ?  I just committed that last night, and although it does not seem to be
> related, who knows.
>
> Andy
> --
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