From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 99167 invoked by alias); 7 Oct 2016 09:19:07 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 96797 invoked by uid 89); 7 Oct 2016 09:19:05 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.0 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RCVD_IN_DNSWL_LOW,RCVD_IN_SEMBACKSCATTER autolearn=no version=3.3.2 spammy=INSTALL, recommendation, dumped, H*MI:3457 X-HELO: mx0a-001b2d01.pphosted.com Subject: Re: [PATCH v3 1/9] Add configure check to test if gcc supports attribute ifunc. To: libc-alpha@sourceware.org References: <1472047472-30307-1-git-send-email-stli@linux.vnet.ibm.com> From: Stefan Liebler Date: Fri, 07 Oct 2016 09:19:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <1472047472-30307-1-git-send-email-stli@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16100709-0020-0000-0000-000002104170 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16100709-0021-0000-0000-00001DD02582 Message-Id: <049007cd-3457-9aa2-5561-b7c1df88e766@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-10-07_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=14 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1610070165 X-SW-Source: 2016-10/txt/msg00163.txt.bz2 Hi, as all patches are acked I've pushed the series. I also opened the bug "Bug 77894 - Enable GNU indirect function support by default as it will be used in glibc." (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77894) against gcc and sent a note to the distribution maintainers listed in https://sourceware.org/glibc/wiki/MAINTAINERS#Distribution_Maintainers. Thanks. Stefan On 08/24/2016 04:04 PM, Stefan Liebler wrote: > This patch adds a configure check to test if gcc supports attribute ifunc. > The support can either be enabled in /gcc/config.gcc for one > architecture in general by setting default_gnu_indirect_function variable to yes > or by configuring gcc with --enable-gnu-indirect-function. > > The next patch rewrites libc_ifunc macro to use gcc attribute ifunc instead > of inline assembly to generate the IFUNC symbols due to false debuginfo. > > If gcc does not support attribute ifunc, the old approach for generating > ifunc'ed symbols is used. Then the debug-information is false. Thus it is > recommended to use a gcc with indirect function support (See notes in INSTALL). > After this patch-series these inline assemblies for ifunc-handling are not > scattered in multiple files but are used only indirect via ifunc-macros > and can simply removed in libc-symbols.h in future. > > --- > INSTALL | 8 ++++++++ > If glibc is configured with --enable-multi-arch and gcc does not support > attribute ifunc, a configure warning is dumped! > > This NEWS entry will be added: > * For multi-arch support it is recommended to use a GCC with gnu-indirect-function > support as it is used to generate ifunc'ed symbols with correct > debug-information. This support can either be enabled by configuring GCC with > '--enable-gnu-indirect-function' or by enabling it by default by setting > 'default_gnu_indirect_function' variable for a particular architecture in > gcc source file 'gcc/config.gcc'. > > ChangeLog: > > * config.h.in (HAVE_GCC_IFUNC): New undef. > * configure.ac: Add check if gcc supports attribute ifunc feature. > * configure: Regenerated. > * manual/install.texi: Add recommendation for gcc with > indirect-function support. > * INSTALL: Regenerated.