From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <pab@pabigot.com>
Received: from p3plsmtpa09-10.prod.phx3.secureserver.net
	(p3plsmtpa09-10.prod.phx3.secureserver.net [173.201.193.239])
	by mail.openembedded.org (Postfix) with ESMTP id CCB7165C68
	for <openembedded-core@lists.openembedded.org>;
	Tue, 12 Aug 2014 00:12:05 +0000 (UTC)
Received: from [192.168.65.10] ([66.41.60.82])
	by p3plsmtpa09-10.prod.phx3.secureserver.net with 
	id dcC51o0061mTNtu01cC5J4; Mon, 11 Aug 2014 17:12:07 -0700
Message-ID: <53E95BD4.5090007@pabigot.com>
Date: Mon, 11 Aug 2014 19:12:04 -0500
From: "Peter A. Bigot" <pab@pabigot.com>
Organization: Peter Bigot Consulting, LLC
User-Agent: Mozilla/5.0 (X11; Linux x86_64;
	rv:31.0) Gecko/20100101 Thunderbird/31.0
MIME-Version: 1.0
To: openembedded-core@lists.openembedded.org
References: <53E9134F.7040108@pabigot.com>
In-Reply-To: <53E9134F.7040108@pabigot.com>
Subject: Re: Yocto development with C++11 threads and gcc
X-BeenThere: openembedded-core@lists.openembedded.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Patches and discussions about the oe-core layer
	<openembedded-core.lists.openembedded.org>
List-Unsubscribe: <http://lists.openembedded.org/mailman/options/openembedded-core>,
	<mailto:openembedded-core-request@lists.openembedded.org?subject=unsubscribe>
List-Archive: <http://lists.openembedded.org/pipermail/openembedded-core/>
List-Post: <mailto:openembedded-core@lists.openembedded.org>
List-Help: <mailto:openembedded-core-request@lists.openembedded.org?subject=help>
List-Subscribe: <http://lists.openembedded.org/mailman/listinfo/openembedded-core>,
	<mailto:openembedded-core-request@lists.openembedded.org?subject=subscribe>
X-List-Received-Date: Tue, 12 Aug 2014 00:12:10 -0000
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit

On 08/11/2014 02:02 PM, Peter A. Bigot wrote:
> The program below built on the target with the MACHINE=beaglebone 
> gcc-4.9.1 compiler from Yocto/OpenEmbedded poky master produces this 
> error:
>
> beaglebone[52]$ g++ -std=c++1y -pthread test.cc && ./a.out
> starting
> joining
> pure virtual method called
> terminate called without an active exception
> Aborted (core dumped)
>
> When the program is recompiled with the defines for 
> __GCC_HAVE_SYNC_COMPARE_AND_SWAP_X enabled as suggested at 
> https://groups.google.com/d/msg/automatak-dnp3/Jisp_zGhd5I/ck_Cj6nO8joJ it 
> works:
>
> beaglebone[53]$ g++ -std=c++1y -pthread test.cc && ./a.out
> starting
> joining
> doit
> done
>
> Preliminary analysis confirms that the built-ins for those defines are 
> not being added by the compiler because it thinks the target doesn't 
> support those operations.  Nonetheless, it doesn't use the substitutes 
> that are obviously available.
>
> Can anybody recall anything about the way GCC is built under OE that 
> would explain this?

Not an OE problem.  See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62100

I'm testing a patch locally and awaiting GCC maintainer comment before 
proposing it for OE.

Peter

>
> Peter
>
> /* g++ -std=c++1y -pthread test.cc && ./a.out */
> #if 0
> #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1
> #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2
> #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
> #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
> #endif
>
> #include <iostream>
> #include <thread>
>
> void
> doit ()
> {
>   std::cerr << "doit\n";
> }
>
> int main (int argc,
>           char * argv [])
> {
>   std::cerr << "starting\n";
>   std::thread thr{doit};
>   std::cerr << "joining\n";
>   thr.join();
>   std::cerr << "done\n";
>   return 0;
> }
>