From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id DF18146012; Wed, 8 Jan 2025 03:46:50 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 4306A40150; Wed, 8 Jan 2025 03:46:50 +0100 (CET) Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by mails.dpdk.org (Postfix) with ESMTP id 0572F4014F for ; Wed, 8 Jan 2025 03:46:48 +0100 (CET) Received: by linux.microsoft.com (Postfix, from userid 1213) id 0B33A203E381; Tue, 7 Jan 2025 18:46:48 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0B33A203E381 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1736304408; bh=IhtlSVkGokRE6QZNyVKalBJrLi4WgyCB24PJ865aYJs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DoVqToZfjL/2sIplu4NrLdSCgD3VmloM88icO8ELcoAmzaaDOSWGP+Ro5psq4V9vS LO8E3KcavsfFcjs5QA3K/5vRoHfYyI+I2c8XoSmzSi68TmWFeWop2Q92bKtKrfr1nP xv2DS4Ry7C3RMpgExzqG8PYwz84Wci1Zwe+aeoZU= Date: Tue, 7 Jan 2025 18:46:48 -0800 From: Andre Muezerie To: Bruce Richardson Cc: Stephen Hemminger , dev@dpdk.org Subject: Re: [PATCH v11 0/3] add diagnostics macros to make code portable Message-ID: <20250108024647.GA15780@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> References: <1735263196-2809-1-git-send-email-andremue@linux.microsoft.com> <1735918611-17374-1-git-send-email-andremue@linux.microsoft.com> <20250103112402.64bf2d96@pi5> <20250103212634.GA24552@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Mon, Jan 06, 2025 at 11:00:15AM +0000, Bruce Richardson wrote: > On Fri, Jan 03, 2025 at 01:26:34PM -0800, Andre Muezerie wrote: > > On Fri, Jan 03, 2025 at 11:24:02AM -0800, Stephen Hemminger wrote: > > > On Fri, 3 Jan 2025 07:36:48 -0800 > > > Andre Muezerie wrote: > > > > > > > From: Andre Muezerie > > > > To: andremue@linux.microsoft.com > > > > Cc: dev@dpdk.org, stephen@networkplumber.org > > > > Subject: [PATCH v11 0/3] add diagnostics macros to make code portable > > > > Date: Fri, 3 Jan 2025 07:36:48 -0800 > > > > X-Mailer: git-send-email 1.8.3.1 > > > > > > > > It was a common pattern to have "GCC diagnostic ignored" pragmas > > > > sprinkled over the code and only activate these pragmas for certain > > > > compilers (gcc and clang). Clang supports GCC's pragma for > > > > compatibility with existing source code, so #pragma GCC diagnostic > > > > and #pragma clang diagnostic are synonyms for Clang > > > > (https://clang.llvm.org/docs/UsersManual.html). > > > > > > > > Now that effort is being made to make the code compatible with MSVC > > > > these expressions would become more complex. It makes sense to hide > > > > this complexity behind macros. This makes maintenance easier as these > > > > macros are defined in a single place. As a plus the code becomes > > > > more readable as well. > > > > > > Since 90% of these cases are about removing const from a pointer, > > > maybe it would be better to have a macro that did that? > > > > > > Would not work for base driver code which is pretending to be platform independent. > > > > Most of the warnings I've seen were about dropping the volatile qualifier, like the one below: > > > > ../drivers/net/i40e/i40e_rxtx_vec_sse.c:42:32: warning: cast from 'volatile struct i40e_32byte_rx_desc::(unnamed at ../drivers/net/i40e/base/i40e_type.h:803:2) *' to '__attribute__((__vector_size__(2 * sizeof(long long)))) long long *' drops volatile qualifier [-Wcast-qual] > > 42 | _mm_store_si128((__m128i *)&rxdp[i].read, > > | ^ > > > > To make sure I understood your suggestion correctly, you're proposing to replace this > > > > __rte_diagnostic_push > > __rte_diagnostic_ignored_wcast_qual > > _mm_store_si128((__m128i *)&rxdp[i].read, dma_addr0); > > __rte_diagnostic_pop > > > > > > with something like this? > > > > _mm_store_si128(RTE_IGNORE_CAST_QUAL((__m128i *)&rxdp[i].read), dma_addr0); > > > > This could be done, and I think it does look better, despite the slight line length increase. > > +1 for this option. One macro can be used to drop all qualifiers, both > const and volatile, right? Yes, a single macro can drop all qualifiers. I did realize though that the macro must involve the entire expression - it cannot be used just around one parameter, unfortunately. It would look like: RTE_IGNORE_CAST_QUAL(_mm_store_si128((__m128i *)&rxdp[i].read, dma_addr0);) This is still the same line length as before, but not as elegant. For some code blocks where many consecutive lines (4+) would require this macro I feel that it might still make sense to use __rte_diagnostic_ignored_wcast_qual, because using RTE_IGNORE_CAST_QUAL might result in additional lines anyways due to 80 column width limit. I'm planning to submit a new version of the patchset with this mixed approach unless there are objections.