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=-11.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 D6968C7618B for ; Mon, 29 Jul 2019 16:21:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B04A6206BA for ; Mon, 29 Jul 2019 16:21:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="QNUdnwD+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728671AbfG2QVq (ORCPT ); Mon, 29 Jul 2019 12:21:46 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:33112 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727576AbfG2QVq (ORCPT ); Mon, 29 Jul 2019 12:21:46 -0400 Received: by mail-pl1-f196.google.com with SMTP id c14so27638440plo.0 for ; Mon, 29 Jul 2019 09:21:46 -0700 (PDT) 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=6c39aHCrPSADKgn1QA3sQ/OzJg2W7CUxLj9xwpXNwm8=; b=QNUdnwD+0BnljNKmpSMc4dq1BHiw94BWEcKU6fhvEQa03/4iKV41fAYISj+UN/3NAL 4U3SKSKjVySDfUikKeS7kxUw15lpQOIY6MO0E7z+KYjC5MJLO6LXo0+jxLdjCRpKdisd 9d5GqsNYlbc9jvHYMxRLbYC1fQPIgz7J9VZ1gGCGAzc+2MhgJW88fvuhsEJRZIKOKUSm wj/WB4k+6L+qzQLCI4Grpkmjj+3If7uPvcS7y1u6H1mDyYfeVqylpARfkL1K0KmJWas6 C+NAm3hah4FzqYYgR7uaMLyyl7qdKYmPl2O3w4Y3EIwOGUb+aq/Ro29iUmqbaubuzhqO Fpog== 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=6c39aHCrPSADKgn1QA3sQ/OzJg2W7CUxLj9xwpXNwm8=; b=DFU7VBDRvjWvt4Gy8cCbvIsaVzbKIDrSwm44BYysRUGIGdTBhfvdRo3Sjx3m2jg845 /8imH0PduZI4naYnG5Vnm/zDYiPR4U7pxO+tOC3BvN2q7aV3kUmNBRztqePZfjKn2/Gz HkblqrAYDt1rez+PWbDRHgb9f8+JVIVocPmDjJpcPATVOv6VN4wTNIIPESajut5IaVQX WtyMipOIsIEhDPqEcDl5qnj5DDLNFWitYVZPbX3y9VBlqc+2aOMMlWLDsYDz/DGfqq65 +5LQF15/gMZoXVLuXtozH6WXa2+EXanCvgwL2ZGaF9YigzFXHadA3sqaBIHtLnMFUzGf EFmw== X-Gm-Message-State: APjAAAVQT9+Jpzm3Ye2RQjDyTdROejLWRvw60Z2snpjSF7TjL3kqlUvF ijLulyZDpK/HU+vd6TpKDCGWbiVXXw+eZT0DzHg8EA== X-Google-Smtp-Source: APXvYqxNskZ/KQ64ZtfmGcktH0OJHpIo2HF39Q8rmuazafjjU1buTQDpZhkJSEFFXEE2fvgDHJElTStCCkxLT6/DleE= X-Received: by 2002:a17:902:e703:: with SMTP id co3mr13856835plb.119.1564417305124; Mon, 29 Jul 2019 09:21:45 -0700 (PDT) MIME-Version: 1.0 References: <20190729091517.5334-1-yamada.masahiro@socionext.com> <20190729160412.GA100132@archlinux-threadripper> In-Reply-To: <20190729160412.GA100132@archlinux-threadripper> From: Nick Desaulniers Date: Mon, 29 Jul 2019 09:21:33 -0700 Message-ID: Subject: Re: [PATCH] kbuild: initialize CLANG_FLAGS correctly in the top Makefile To: Nathan Chancellor Cc: Masahiro Yamada , Linux Kbuild mailing list , Stephen Boyd , "# 3.4.x" , Michal Marek , clang-built-linux , LKML 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, Jul 29, 2019 at 9:04 AM Nathan Chancellor wrote: > > On Mon, Jul 29, 2019 at 06:15:17PM +0900, Masahiro Yamada wrote: > > CLANG_FLAGS is initialized by the following line: > > > > CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%)) > > > > ..., which is run only when CROSS_COMPILE is set. > > > > Some build targets (bindeb-pkg etc.) recurse to the top Makefile. > > > > When you build the kernel with Clang but without CROSS_COMPILE, > > the same compiler flags such as -no-integrated-as are accumulated > > into CLANG_FLAGS. > > > > If you run 'make CC=clang' and then 'make CC=clang bindeb-pkg', > > Kbuild will recompile everything needlessly due to the build command > > change. > > > > Fix this by correctly initializing CLANG_FLAGS. > > > > Fixes: 238bcbc4e07f ("kbuild: consolidate Clang compiler flags") > > Cc: # v4.20+ > > Signed-off-by: Masahiro Yamada > > Reviewed-by: Nathan Chancellor Acked-by: Nick Desaulniers -- Thanks, ~Nick Desaulniers