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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 8DA80C35E15 for ; Tue, 25 Feb 2020 20:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5EC192176D for ; Tue, 25 Feb 2020 20:59:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qYTPCkYA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729580AbgBYU7i (ORCPT ); Tue, 25 Feb 2020 15:59:38 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:42949 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726764AbgBYU7h (ORCPT ); Tue, 25 Feb 2020 15:59:37 -0500 Received: by mail-pg1-f193.google.com with SMTP id h8so137227pgs.9 for ; Tue, 25 Feb 2020 12:59:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=l4iIiKgZ3F5fVRZU+jMxKAB1P3b/lgfIZbluQQ7RBgg=; b=qYTPCkYAahUF4zPxst0kQF5J8/vc/2BezBXHhhRlDOYeqgskoi2uAFCUYtJ/jzZfWS 5dffLkxHLwzHR8R+vUtRRZHjOQlymJLdgOnB8zDaYgd/xzVpeJfbH8ggSiG+tlewjtzX WCprmfHB4VCsjxXC5f9dGqb9V8mmaJx42e8kcL6enZ0a6wLEnFraVjlH15ieiFOBD0DA e+1+nq0Mu55AYqf5YP9EP4dl+TzEDeAN+AcdZtvhU6OxQIogDdfKGdQe5LHEyO39pSZt 4HUHFndr7cMDtI2NtlJrXLQxrzNiCGEg+wSMjI/Y47ABvuw1ioz9fQzZqQjmfHQUkuXT ugLg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=l4iIiKgZ3F5fVRZU+jMxKAB1P3b/lgfIZbluQQ7RBgg=; b=Y8TfaosKhynvgMA8pUT1O1GRKGAeRDa/wLDXu8pGCYYpEMbzCMb/gIJ2NYvNrtmThM rFjPP2W1nJVrMSMP2efCzjIpiyjcswF+45hQQ8KKCDoaUZI9MR7AzSnvHaR9H3/WRHzM qyxfkm0m6NCszlQX78eKddReIHnpM8WqwSOVLVMsPZ3KZQJ6F1KhYQjTQqu76jQ5Ivlt sqJXc9L15G4rPTyk6siaLvQtAPFNOnDNC8Rk1Eguk8kj+JcIZquQQlO70Z+Gh8rBGs+U tLSPX6UEV6Wr1vzZe/4F2w01Iucxm93oacIayi1H2I9cAvLGx5ka1+rdwDrsN+3YqSC0 KWgg== X-Gm-Message-State: APjAAAWFdkPxFM91P+vkwC9nDf9vv0fzj/UUZGSKssttwrxRrvTXlS54 HnCzJLf47B2q6uVD8mLPquA0XTk1hiWUnPfu2DlP6g== X-Google-Smtp-Source: APXvYqzLuZWs29B9hUeIcVf8Zmto6Gx+iGZUlBReKdtGQkRIb/Vk49VhQ/NAnYYH0v5R4SQAoVrwGFn0m1gnqnK80+c= X-Received: by 2002:a63:4e22:: with SMTP id c34mr371057pgb.263.1582664376061; Tue, 25 Feb 2020 12:59:36 -0800 (PST) MIME-Version: 1.0 References: <20200224174129.2664-1-ndesaulniers@google.com> <202002242003.870E5F80@keescook> <20200225041643.GA17425@ubuntu-m2-xlarge-x86> In-Reply-To: <20200225041643.GA17425@ubuntu-m2-xlarge-x86> From: Nick Desaulniers Date: Tue, 25 Feb 2020 12:59:25 -0800 Message-ID: Subject: Re: [PATCH] Documentation/llvm: add documentation on building w/ Clang/LLVM To: Nathan Chancellor Cc: Kees Cook , Jonathan Corbet , Masahiro Yamada , Michal Marek , Linux Kbuild mailing list , Linux Doc Mailing List , LKML , clang-built-linux Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 24, 2020 at 8:16 PM Nathan Chancellor wrote: > > Should this also include an update to Documentation/process/changes.rst > > with the minimum version required? (I would expect this to be "9" for Clang, > > and "11" for ld.lld.) > > I think the clang one should be added in a separate patch that > solidifies that in include/linux/compiler-clang.h with a CLANG_VERSION > macro and version check, like in include/linux/compiler-gcc.h. > > ld.lld's minimum version should also be 9, what is the blocking issue > that makes it 11? I'm super hesitant to put a minimally required version of Clang, since it really depends on the configs you're using. Sure, clang-9 will probably work better than clang-4 for some configs, but I would say ToT clang built from source would be even better, as unrealistic as that is for most people. The question of "what's our support model" hasn't realistically come up yet, so I don't really want to make a decision on that right now and potentially pigeonhole us into some support scheme that's theoretical or hypothetical. We need to expand out the CI more, and get more people to even care about Clang, before we start to concern ourselves with providing an answer to the question "what versions of clang are supported?" But it's just a strong opinion of mine, held loosely. Either way, it can be done (or not) in a follow up patch. I would like to land some Documentation/ even if it's not perfect, we can go from there. -- Thanks, ~Nick Desaulniers