From: Jeff Law <law@redhat.com>
To: Florian Weimer <fweimer@redhat.com>,
Jonathan Wakely <jwakely.gcc@gmail.com>
Cc: Sandra Loosemore <sandra@codesourcery.com>,
Jakub Jelinek <jakub@redhat.com>,
Jeff Prothero <jprother@altera.com>,
"gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: Re: Obscure crashes due to gcc 4.9 -O2 => -fisolate-erroneous-paths-dereference
Date: Fri, 20 Feb 2015 17:32:00 -0000 [thread overview]
Message-ID: <54E76F99.6090809@redhat.com> (raw)
In-Reply-To: <54E76A58.4010401@redhat.com>
On 02/20/15 10:09, Florian Weimer wrote:
> On 02/20/2015 06:01 PM, Jeff Law wrote:
>
>> But that's always true -- this isn't any different than aliasing,
>> arithmetic overflow, etc. The standards define the contract between the
>> compiler/library implementors and the developers. Once the contract is
>> broken, all bets are off.
>
> What I don't like about this case (std::vector<T>::data() returning
> nullptr vs memcpy/memcmp/qsort non-null assertions) is that it is
> internally non-composing in a totally non-obvious way. data() is
> explicitly intended to cover interoperability with these older C
> functions, and it fails.
And that's precisely why I consider this class of issues the most
problematical.
Jeff
next prev parent reply other threads:[~2015-02-20 17:32 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-18 19:24 Jeff Prothero
2015-02-18 19:29 ` Jakub Jelinek
2015-02-19 20:56 ` Sandra Loosemore
2015-02-19 21:16 ` Daniel Gutson
2015-02-19 22:10 ` Jakub Jelinek
2015-02-19 22:26 ` Sandra Loosemore
2015-02-19 21:23 ` Joel Sherrill
2015-02-19 21:56 ` Chris Johns
2015-02-20 17:30 ` Jeff Law
2015-02-26 16:23 ` David Malcolm
2015-02-27 20:55 ` [RFC/patch for stage1] Embed compiler dumps into generated .o files (was Re: Obscure crashes due to gcc 4.9 -O2 => -fisolate-erroneous-paths-dereference) David Malcolm
2015-02-20 11:06 ` Obscure crashes due to gcc 4.9 -O2 => -fisolate-erroneous-paths-dereference Florian Weimer
2015-02-20 11:43 ` Jonathan Wakely
2015-02-20 12:05 ` Florian Weimer
2015-02-20 17:01 ` Jeff Law
2015-02-20 17:09 ` Florian Weimer
2015-02-20 17:32 ` Jeff Law [this message]
2015-02-20 18:01 ` Paul_Koning
2015-02-20 12:11 ` Jakub Jelinek
2015-02-20 17:03 ` Jeff Law
2015-03-03 19:57 ` Martin Sebor
2015-03-03 23:38 ` Jeff Law
2015-03-04 12:36 ` Richard Biener
2015-02-20 12:13 ` Andrew Haley
2015-02-20 17:03 ` Jeff Law
2015-02-18 19:30 ` Andrew Pinski
2015-02-20 9:30 ` Andrew Haley
2015-02-20 11:45 ` Florian Weimer
2015-02-20 17:01 ` Jeff Law
2015-02-20 18:07 ` Paul_Koning
2015-02-20 1:04 Jeff Prothero
2015-02-27 22:13 Manuel López-Ibáñez
2015-03-03 8:41 ` Chris Johns
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