From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752639AbeDDGQt (ORCPT ); Wed, 4 Apr 2018 02:16:49 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:60778 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643AbeDDGQs (ORCPT ); Wed, 4 Apr 2018 02:16:48 -0400 Subject: Re: [PATCH v2] tools include: define READ_ONCE/WRITE_ONCE for C++ To: linux-kernel@vger.kernel.org Cc: Li Zhijian , acme@redhat.com, philip.li@intel.com, mark.rutland@arm.com, paulmck@linux.vnet.ibm.com, mingo@kernel.org References: <1512005772-27112-1-git-send-email-lizhijian@cn.fujitsu.com> From: Sandipan Das Date: Wed, 4 Apr 2018 11:46:38 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <1512005772-27112-1-git-send-email-lizhijian@cn.fujitsu.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18040406-0044-0000-0000-000005433751 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18040406-0045-0000-0000-000028834C3E Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-04-04_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804040065 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 11/30/2017 07:06 AM, Li Zhijian wrote: > since 6aa7de0, we failed to build perf with C++(clang) > to fix the following compile errors > -------------- > lizhijian@haswell-OptiPlex-9020:~/lkp/linux/tools/perf$ make LLVM_CONFIG=/usr/bin/llvm-config-3.9 LIBCLANGLLVM=1 > ... > CC util/probe-finder.o > In file included from /home/lizj/linux/tools/perf/util/util.h:13:0, > from /home/lizj/linux/tools/perf/util/util-cxx.h:20, > from util/c++/clang-c.h:5, > from util/c++/clang-test.cpp:2: > /home/lizj/linux/tools/include/asm/../../arch/x86/include/asm/atomic.h: In function ‘int atomic_read(const atomic_t*)’: > /home/lizj/linux/tools/include/linux/compiler.h:157:45: error: use of deleted function ‘atomic_read(const atomic_t*)::::()’ > ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) > ^ > /home/lizj/linux/tools/include/asm/../../arch/x86/include/asm/atomic.h:28:9: note: in expansion of macro ‘READ_ONCE’ > return READ_ONCE((v)->counter); > ^ > /home/lizj/linux/tools/include/linux/compiler.h:157:11: note: ‘atomic_read(const atomic_t*)::::()’ is implicitly deleted because the default definition would be ill-formed: > ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) > ^ > /home/lizj/linux/tools/include/asm/../../arch/x86/include/asm/atomic.h:28:9: note: in expansion of macro ‘READ_ONCE’ > return READ_ONCE((v)->counter); > ^ > /home/lizj/linux/tools/include/linux/compiler.h:157:11: error: uninitialized const member in ‘union atomic_read(const atomic_t*)::’ > ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) > ^ > /home/lizj/linux/tools/include/asm/../../arch/x86/include/asm/atomic.h:28:9: note: in expansion of macro ‘READ_ONCE’ > return READ_ONCE((v)->counter); > ^ > /home/lizj/linux/tools/include/linux/compiler.h:157:23: note: ‘const int atomic_read(const atomic_t*)::::__val’ should be initialized > ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) > ^ > /home/lizj/linux/tools/include/asm/../../arch/x86/include/asm/atomic.h:28:9: note: in expansion of macro ‘READ_ONCE’ > return READ_ONCE((v)->counter); > ^ > LD tests/perf-in.o > ... > -------------- > I ran into the same problems while building perf with clang support. If the solution proposed here is acceptable, can someone please pick up this patch? -- With Regards, Sandipan