From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F322C43382 for ; Wed, 26 Sep 2018 18:00:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0D1F42147D for ; Wed, 26 Sep 2018 18:00:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="bls8IzGM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D1F42147D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727427AbeI0AO1 (ORCPT ); Wed, 26 Sep 2018 20:14:27 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:33097 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725937AbeI0AO1 (ORCPT ); Wed, 26 Sep 2018 20:14:27 -0400 Received: by mail-pf1-f194.google.com with SMTP id d4-v6so13840751pfn.0 for ; Wed, 26 Sep 2018 11:00:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=uXIwahuaS+t2PQbti3lmHWJPn0xFUyZCUXsmrWQpQL4=; b=bls8IzGM9J8y0J2ofAzIk4TQT+VpiYHiNgWBuhhZwVqiO6mFPe8zEq5Sk36j+Tsvo0 gCV8oox0Ea2SXLM2/sq1OM3T/zI8lXILhEcFblSHexqT5UaiOBOHWHd2DyQsRKOrStt7 2Ng+aIZPjDDbg33f5922IG5tpEVFoWf8TNm9M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=uXIwahuaS+t2PQbti3lmHWJPn0xFUyZCUXsmrWQpQL4=; b=ZxCJtwMNP5nv9hBtTwz6RDcQEd6TdJxYxCJ5ObC+adDrbGH5tc07W/GFGzhE2dDop4 UuehCcGqsX2MoXQaGqdYxJjJ5RkDOF4hjBW7Rrz95qFRND5NLqmjgGClVSkKfNB+LnoK 0ODkxlYCvTUcfcO1n3xgtKWOwTrPTEwpQIpJG5PcSCYzFlSzrB9e3XMM6waHyrpt9SUb F0GVPjL9R9ICz/0BBSaRmoY+9kLCkGfw6BRQ5eGaczPteGSImjPiTXEBvTjnjcmbyPI5 cVo0QHgEz2ScvCfN6XgSTV5MIxCTPBoIO/FZZ0f+7DNDQQQcre5eUId/9fGNV5Ajj/8t Iepg== X-Gm-Message-State: ABuFfoiKbTzSl6ZcnHCwtFbww/7jSuj0Ijr6FJLzIDASx2OOUwQkwJoH ieVfv9L4e0O9muwDAw6jDjde/g== X-Google-Smtp-Source: ACcGV63nfdMhzeowuIATub8X4L2uV19LEKKm9uJ8GTPiQqj9TBBH6wtpOmiATY+XLV11rJFITJ8Vgw== X-Received: by 2002:a62:d286:: with SMTP id c128-v6mr6096876pfg.14.1537984820679; Wed, 26 Sep 2018 11:00:20 -0700 (PDT) Received: from localhost ([2620:15c:202:1:b6af:f85:ed6c:ac6a]) by smtp.gmail.com with ESMTPSA id a15-v6sm9516778pfe.32.2018.09.26.11.00.19 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 26 Sep 2018 11:00:19 -0700 (PDT) Date: Wed, 26 Sep 2018 11:00:19 -0700 From: Matthias Kaehlcke To: Nick Desaulniers Cc: Linus Torvalds , Masahiro Yamada , Kees Cook , sparse@chrisli.org, linux-sparse@vger.kernel.org, LKML , daniel.santos@pobox.com, Chris Wilson , Jani Nikula Subject: Re: [PATCH v2] compiler.h: give up __compiletime_assert_fallback() Message-ID: <20180926180019.GD22824@google.com> References: <1535220989-27645-1-git-send-email-yamada.masahiro@socionext.com> <84cf6ae0-97c8-6b73-ca86-b3d3b3daba5b@pobox.com> <8d5cf8c6-556a-96a1-610d-c92355783a9f@pobox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 31, 2018 at 09:46:02AM -0700, Nick Desaulniers wrote: > On Tue, Aug 28, 2018 at 4:00 PM Nick Desaulniers > wrote: > > > > On Mon, Aug 27, 2018 at 1:42 PM Daniel Santos wrote: > > > > > > Hello Nick, > > > > > > On 08/27/2018 03:09 PM, Nick Desaulniers wrote: > > > >>> Let's give up __compiletime_assert_fallback(). This commit does not > > > >>> change the current behavior since it just rips off the useless code. > > > >> Clang is not the only target audience of > > > >> __compiletime_assert_fallback(). Instead of ripping out something that > > > >> may benefit builds with gcc 4.2 and earlier, why not override its > > > > Note that with commit cafa0010cd51 ("Raise the minimum required gcc > > > > version to 4.6") that gcc < 4.6 is irrelevant. > > > > > > Ah, I guess I'm not keeping up, that's wonderful news! Considering that > > > I guess I would be OK with its removal, but I still think it would be > > > better if a similar mechanism to break the Clang build could be found. > > > > I'm consulting with our best language lawyers to see what combinations > > of _Static_assert and __builtin_constant_p would do the trick. > > Linus, > Can this patch be merged in the meantime? friendly ping :) With c5c2b11894f4 ("drm/i915: Warn against variable length arrays") clang raises plenty of vla warnings about __compiletime_error_fallback() in the i915 driver. Would be great to get rid of those without having to revert that commit.