Re: 'stack overflow' message for Darwin; host hooks

[Geoffrey Keating <geoffk at apple dot com>]

On Thursday, February 6, 2003, at 12:34  PM, Zack Weinberg wrote:

> Geoffrey Keating <geoffk@apple.com> writes:
>
> > On Wednesday, February 5, 2003, at 10:20  PM, Zack Weinberg wrote:
> > > Cute, but would you mind putting some thought into a way to avoid a
> > > re-proliferation of x-fragments?  I went to considerable effort to 
> > > get
> > > within epsilon of being able to eliminate that facility entirely.
> > Yes, there's a way to eliminate all the new x-fragments and a bunch of
> > t-fragments too: automatic dependency generation.
> Okay, that gives me additional incentive to get automatic dependency
> generation going.  (I have a plan; finding time is another question.)
I'd really like automatic dependencies.  Our dependencies keep getting 
out-of-date.

> > > I thought we had code in toplev.c to call rlimit() to set the soft
> > > stack limit as high as it could go, rather than bothering the user
> > > about it.
> > No, we don't; that would be bad, if the user sets a limit we should
> > honour it.
> I'm of two minds here.  On the one hand, honoring the user's limits is
> a good thing; on the other hand, we know that the default stack limit
> is too low for us on Darwin and it seems to me that we ought not to
> make the user worry about that.
It's too low for some highly atypical test cases, but in real programs 
the limit is not a problem.

> Maybe the *real* right thing is to figure out why we still need so
> much stack and change that.  I remember that some work was done in
> the past on allocating huge arrays with malloc instead of alloca...
I haven't investigated all the cases, but at least for one test case 
the cause was real recursion in walk_tree (thousands of levels deep).