From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by sourceware.org (Postfix) with ESMTPS id 053083858D37 for ; Tue, 30 Jun 2020 08:14:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 053083858D37 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=tdevries@suse.de X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 0A442AAC3; Tue, 30 Jun 2020 08:14:32 +0000 (UTC) Subject: Re: [committed][gdb/testsuite] Update psym-external-decl.exp for gcc-10/clang To: Pedro Alves , Gary Benson Cc: gdb-patches@sourceware.org References: <20200502075127.GA21196@delia> <20200617122432.GA28940@blade.nx> <20200618161044.GA1032@blade.nx> <21d9fcc8-62c4-d1a5-f085-0c7f26783255@suse.de> <20200619140041.GB31823@blade.nx> <6dd30362-e9dd-6bc9-bf40-8b846b926e5a@suse.de> <20200626093727.GA8682@blade.nx> From: Tom de Vries Autocrypt: addr=tdevries@suse.de; keydata= xsBNBF0ltCcBCADDhsUnMMdEXiHFfqJdXeRvgqSEUxLCy/pHek88ALuFnPTICTwkf4g7uSR7 HvOFUoUyu8oP5mNb4VZHy3Xy8KRZGaQuaOHNhZAT1xaVo6kxjswUi3vYgGJhFMiLuIHdApoc u5f7UbV+egYVxmkvVLSqsVD4pUgHeSoAcIlm3blZ1sDKviJCwaHxDQkVmSsGXImaAU+ViJ5l CwkvyiiIifWD2SoOuFexZyZ7RUddLosgsO0npVUYbl6dEMq2a5ijGF6/rBs1m3nAoIgpXk6P TCKlSWVW6OCneTaKM5C387972qREtiArTakRQIpvDJuiR2soGfdeJ6igGA1FZjU+IsM5ABEB AAHNH1RvbSBkZSBWcmllcyA8dGRldnJpZXNAc3VzZS5kZT7CwKsEEwEIAD4WIQSsnSe5hKbL MK1mGmjuhV2rbOJEoAUCXSW0JwIbAwUJA8JnAAULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAh CRDuhV2rbOJEoBYhBKydJ7mEpsswrWYaaO6FXats4kSgc48H/Ra2lq5p3dHsrlQLqM7N68Fo eRDf3PMevXyMlrCYDGLVncQwMw3O/AkousktXKQ42DPJh65zoXB22yUt8m0g12xkLax98KFJ 5NyUloa6HflLl+wQL/uZjIdNUQaHQLw3HKwRMVi4l0/Jh/TygYG1Dtm8I4o708JS4y8GQxoQ UL0z1OM9hyM3gI2WVTTyprsBHy2EjMOu/2Xpod95pF8f90zBLajy6qXEnxlcsqreMaqmkzKn 3KTZpWRxNAS/IH3FbGQ+3RpWkNGSJpwfEMVCeyK5a1n7yt1podd1ajY5mA1jcaUmGppqx827 8TqyteNe1B/pbiUt2L/WhnTgW1NC1QDOwE0EXSW0JwEIAM99H34Bu4MKM7HDJVt864MXbx7B 1M93wVlpJ7Uq+XDFD0A0hIal028j+h6jA6bhzWto4RUfDl/9mn1StngNVFovvwtfzbamp6+W pKHZm9X5YvlIwCx131kTxCNDcF+/adRW4n8CU3pZWYmNVqhMUiPLxElA6QhXTtVBh1RkjCZQ Kmbd1szvcOfaD8s+tJABJzNZsmO2hVuFwkDrRN8Jgrh92a+yHQPd9+RybW2l7sJv26nkUH5Z 5s84P6894ebgimcprJdAkjJTgprl1nhgvptU5M9Uv85Pferoh2groQEAtRPlCGrZ2/2qVNe9 XJfSYbiyedvApWcJs5DOByTaKkcAEQEAAcLAkwQYAQgAJhYhBKydJ7mEpsswrWYaaO6FXats 4kSgBQJdJbQnAhsMBQkDwmcAACEJEO6FXats4kSgFiEErJ0nuYSmyzCtZhpo7oVdq2ziRKD3 twf7BAQBZ8TqR812zKAD7biOnWIJ0McV72PFBxmLIHp24UVe0ZogtYMxSWKLg3csh0yLVwc7 H3vldzJ9AoK3Qxp0Q6K/rDOeUy3HMqewQGcqrsRRh0NXDIQk5CgSrZslPe47qIbe3O7ik/MC q31FNIAQJPmKXX25B115MMzkSKlv4udfx7KdyxHrTSkwWZArLQiEZj5KG4cCKhIoMygPTA3U yGaIvI/BGOtHZ7bEBVUCFDFfOWJ26IOCoPnSVUvKPEOH9dv+sNy7jyBsP5QxeTqwxC/1ZtNS DUCSFQjqA6bEGwM22dP8OUY6SC94x1G81A9/xbtm9LQxKm0EiDH8KBMLfQ== Message-ID: Date: Tue, 30 Jun 2020 10:14:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Jun 2020 08:14:34 -0000 On 6/29/20 2:32 PM, Pedro Alves wrote: > On 6/28/20 11:50 AM, Tom de Vries wrote: >> On 6/26/20 11:37 AM, Gary Benson wrote: >>> Tom de Vries wrote: >>>> On 6/19/20 4:00 PM, Gary Benson wrote: >>>>> Tom de Vries wrote: >>>>>> On 6/18/20 6:10 PM, Gary Benson wrote: >>>>>>> Tom de Vries wrote: >>>>>>>> On 6/17/20 2:24 PM, Gary Benson wrote: >>>>>>>>> Tom, I'd like this testcase to not fail silently. Is the >>>>>>>>> functionality under test something that isn't ever >>>>>>>>> expected to work with clang, or is this a test that should >>>>>>>>> pass with clang (but it currently doesn't, for whatever >>>>>>>>> reason)? >>>>>>>> >>>>>>>> I'm not sure. The test can pass with clang, provided it >>>>>>>> generates the required debug info. It currently doesn't. >>>>>>>> Why that is the case, I have no idea. >>>>>>> >>>>>>> I think that means the test should work but it doesn't. Would >>>>>>> you object if I push a patch removing the test-skipping logic? >>>>>>> It will mean an extra FAIL when tested using clang >>>>>> >>>>>> I don't think having a fail for a compiler bug/missing-feature >>>>>> is a good idea. >>>>>> >>>>>> If this is due to a bug/missing-feature in clang, then we need to: >>>>>> - xfail the test, >>>>>> - file the PR in clang, and >>>>>> - reference the PR at the xfail. >>>>> >>>>> Is this a bug/missing feature in clang though? >>>>> How sure are you GDB isn't at fault? >>>> >>>> Clang emits less debug info than GCC. Whether that's a bug, a >>>> missing feature or an explicit unsupported feature in clang, I >>>> don't known. >>>> >>>> I known that gdb isn't at fault. It can't do anything without the >>>> missing debug info. The test was specifically written to use that >>>> debug info. >>> >>> I'm not really sure what's the right thing to do here. >>> >>> On the one hand, my current task is ensuring GDB can debug >>> clang-compiled with clang as well as it can debug GCC-compiled >>> code. From that perspective the skip-if-clang logic in this >>> test is hiding a failure I need to investigate. >>> >>> On the other hand, I'm an engineer working on GDB, and from that >>> perspective I want to be able to run the GDB testsuite and see >>> 100% pass, on whatever setup I test it on. And yes, I know it >>> doesn't... but it *should*. >>> >>> Is there a way to pass a "don't skip clang failures" flag to the >>> testcases, such that people running the testsuite normally would >>> see tests like these return UNSUPPORTED, but I could run the >>> testsuite with the flag so it'd not skip but FAIL wherever the >>> problem is? >> >> I think the following is a good way of dealing with this. >> >> We introduce a proc in gdb.exp called debug_info_for_decl or some such, >> that returns false by default for clang. > > I think it would be useful to include an intro description to > > gdb.base/psym-external-decl.exp > > since it currently doesn't describe what it is testing. Looking > at the commit log of the patch that introduced it helps, but > one shouldn't have to do that. > > So the difference between gcc and clang AFAIU is that gcc emits > debug info for the extern variable declaration (and with newer GCCs, > only if there's a reference to the variable in the CU, otherwise > not even so), while seemingly clang would only emit debug info for > the variable's definition, which isn't compiled with -g, so we > end up with no debug info for the variable. > > I would suggest filing a bug with clang, to confirm whether > this is intentional, or whether they see it as a bug. I would > think it is a bug, but I'm not sure. If indeed a bug, we would > XFAIL the test. > I've filed https://bugs.llvm.org/show_bug.cgi?id=46514 . Thanks, - Tom