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Re: [perl #133327] stack checks make -DDEBUGGING builds incompatiblewith normal ones

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From:
Niko Tyni
Date:
July 4, 2018 20:23
Subject:
Re: [perl #133327] stack checks make -DDEBUGGING builds incompatiblewith normal ones
Message ID:
21238_1530735809_5B3D2CC0_21238_25_1_20180704202311.GA2110@estella.local.invalid
On Wed, Jul 04, 2018 at 05:28:21AM -0700, Dave Mitchell via RT wrote:
> On Tue, Jul 03, 2018 at 08:49:39AM -0700, Niko Tyni (via RT) wrote:

> > Would it be feasible move the -DDEBUGGING check in EXTEND to run time,
> > for instance by calling a function that's a no-op in non-DEBUGGING
> > interpreters, or checking for an interpreter variable that's only set
> > in -DDEBUGGING builds? This has a runtime cost, but I'm not sure how
> > significant that is?
> 
> I wouldn't like any solution that adds extra run-time overhead to
> non-debugging-build XS modules.
> 
> To avoid that, the debugging part of the perl interperter would need to be
> able to determine when it calls an XS sub or a non-core pp_foo() function,
> whether that code what compiled under DEBUGGING. I can't think of a way to
> determine this.

I see.
 
> A fall-back position would be to add support for a PERL_NO_STACK_HWM_CHECK
> define / build option which would completely disable checks, even if
> the core was built with DEBUGGING. That would of course disable
> the check even for XS modules built with DEBUGGING.

Yeah, I suppose we will have to disable the checks in the Debian
debugperl for now. A supported way to do that in 5.30 would be very
much appreciated.

Thanks for looking at this,
-- 
Niko

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