PARI/GP Bug report logs - #1237
undefined behaviour in pari_init_parser

Package: pari; Maintainer for pari is Aurel Page <aurel.page@normalesup.org>; Source for pari is src:pari.

Reported by: Julian Taylor <jtaylor.debian@googlemail.com>

Date: Wed, 31 Aug 2011 15:33:08 UTC

Severity: normal

Done: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>

Bug is archived. No further changes may be made.

Full log

Message #20 received at 1237@pari.math.u-bordeaux.fr (full text, mbox, reply):

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Date: Fri, 2 Sep 2011 18:57:38 +0200
From: Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>
To: Julian Taylor <jtaylor.debian@googlemail.com>
Cc: 1237@pari.math.u-bordeaux.fr
Subject: Re: Bug#1237: undefined behaviour in pari_init_parser
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[Message part 1 (text/plain, inline)]
On Thu, Sep 01, 2011 at 11:00:43PM +0200, Julian Taylor wrote:
> On 09/01/2011 10:22 PM, Bill Allombert wrote:
> >
> >Hello Julian,
> >
> >Undefined according to what rule ? The code is only requiring the adress space to be flat
> >which is true on all supported platforms.
> >
> 
> https://www.securecoding.cert.org/confluence/display/seccode/CC.+Undefined+Behavior#CC.UndefinedBehavior-ub45

Rule ARR36-C is quite excessive: for example it disallows taking the difference
of pointers inside the same malloc'ed block. PARI stack management has always
required this functionality.

> Although it is possible that it is a compiler bug causing this
> issue, this behavior should be fixed somehow too.

Well, you can try the attached patch which work around the compiler issue without
breaking the ABI (tested on sparc).

Cheers,
Bill.

[patch (text/plain, attachment)]

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Bill Allombert <allomber@math.u-bordeaux.fr>. Last modified: Sat Aug 26 17:15:18 2023; Machine Name: pari

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