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From: Jason Merrill <jason@redhat.com>
To: "H.J. Lu" <hjl.tools@gmail.com>,
	       Richard Biener <richard.guenther@gmail.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>,
	       GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: PING^1: [PATCH] Add TYPE_EMPTY_RECORD for C++ empty class
Date: Sat, 12 Dec 2015 14:51:00 -0000	[thread overview]
Message-ID: <566C346B.8030601@redhat.com> (raw)
In-Reply-To: <CAMe9rOrogonLyyMwY8BGs-ue52kO8jKiOH9q1KHxWiicWCFHkA@mail.gmail.com>

On 12/11/2015 06:52 PM, H.J. Lu wrote:
> On Thu, Dec 10, 2015 at 3:24 AM, Richard Biener
> <richard.guenther@gmail.com> wrote:
>> On Wed, Dec 9, 2015 at 10:31 PM, Markus Trippelsdorf
>> <markus@trippelsdorf.de> wrote:
>>> On 2015.12.09 at 10:53 -0800, H.J. Lu wrote:
>>>>
>>>> Empty C++ class is a corner case which isn't covered in psABI nor C++ ABI.
>>>> There is no mention of "empty record" in GCC documentation.  But there are
>>>> plenty of "empty class" in gcc/cp.  This change affects all targets.  C++ ABI
>>>> should specify how it should be passed.
>>>
>>> There is a C++ ABI mailinglist, where you could discuss this issue:
>>> http://sourcerytools.com/cgi-bin/mailman/listinfo/cxx-abi-dev
>>
>> Yep.  As long as the ABI doesn't state how to pass those I'd rather _not_ change
>> GCCs way.
>
> It is agreed that GCC is wrong on this:
>
> http://sourcerytools.com/pipermail/cxx-abi-dev/2015-December/002876.html

Yes, I think this is just a (nasty) bug on some GCC targets.

> Here is the updated patch.   I updated -WpsABI to warn empty
> record which are passed in a variable argument list or aren't the last
> arguments.   They are triggered in:
>
> /export/build/gnu/gcc-x32/build-x86_64-linux/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/bits/hashtable.h:1507:7:
> note: the ABI of passing empty record has changed in GCC 6
 >....

Oof.  Well, at least it's all C++11 stuff, and GCC 5 still defaulted to 
C++98...

Jason

  reply	other threads:[~2015-12-12 14:51 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-08 16:22 H.J. Lu
2015-12-09 14:05 ` Richard Biener
2015-12-09 18:53   ` H.J. Lu
2015-12-09 21:14     ` H.J. Lu
2015-12-09 21:31     ` Markus Trippelsdorf
2015-12-10 11:24       ` Richard Biener
2015-12-11 23:52         ` H.J. Lu
2015-12-12 14:51           ` Jason Merrill [this message]
2015-12-12 15:27             ` Jakub Jelinek
2015-12-12 16:45               ` H.J. Lu
2015-12-12 18:43               ` Marc Glisse
2015-12-14 20:16                 ` Jason Merrill
2015-12-14 20:39                   ` H.J. Lu
2015-12-14 20:44                     ` Jason Merrill
2015-12-14 22:08                       ` H.J. Lu
2016-01-26 19:27                         ` Jason Merrill
2016-01-26 19:52                           ` H.J. Lu
2016-01-26 20:23                             ` Marc Glisse
2016-01-26 20:26                               ` H.J. Lu
2016-01-26 20:44                                 ` Marc Glisse
2016-01-26 21:21                                   ` H.J. Lu
2016-01-26 21:40                                     ` Jakub Jelinek
2016-01-26 22:21                                       ` H.J. Lu
2016-01-27  8:10                                         ` Marc Glisse
2016-01-27  8:21                                           ` Jakub Jelinek
2016-01-27  9:03                                             ` Marc Glisse
2016-01-27 13:46                                               ` H.J. Lu
2016-01-27 15:39                                                 ` H.J. Lu
2016-03-01  1:02                                                   ` Jason Merrill
2016-03-01 22:44                                                     ` H.J. Lu
2016-03-02 16:25                                                       ` Ulrich Weigand
2016-03-02 17:34                                                         ` H.J. Lu
2016-03-15 15:35                                                           ` Jason Merrill
2016-03-15 16:00                                                             ` H.J. Lu
2016-03-15 19:32                                                               ` Jason Merrill
2016-03-16 12:38                                                                 ` H.J. Lu
2016-03-16 16:58                                                                   ` Jason Merrill
2016-03-16 17:02                                                                     ` H.J. Lu
2016-03-16 19:39                                                                       ` H.J. Lu
2016-03-16 19:43                                                                         ` Jason Merrill
2016-03-15 21:40                                                             ` Joseph Myers
2016-03-15 22:31                                                               ` H.J. Lu
2016-03-15 22:35                                                                 ` Joseph Myers
2016-03-16  0:23                                                                   ` H.J. Lu
2016-03-16  0:25                                                                     ` Joseph Myers
2016-03-16  2:17                                                                       ` H.J. Lu
2016-03-16  9:46                                                                         ` Bernhard Reutner-Fischer
2016-03-16 11:53                                                                           ` H.J. Lu
2016-03-16  2:51                                                                       ` Jason Merrill
2016-03-16 11:55                                                                         ` H.J. Lu
2016-03-16 14:33                                                                           ` Jason Merrill
2016-03-16 14:48                                                                             ` H.J. Lu

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