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=-13.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,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 65400C169C4 for ; Fri, 8 Feb 2019 17:46:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E49220863 for ; Fri, 8 Feb 2019 17:46:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="t7UJ39DY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727548AbfBHRp6 (ORCPT ); Fri, 8 Feb 2019 12:45:58 -0500 Received: from mail-ed1-f66.google.com ([209.85.208.66]:45174 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726869AbfBHRp6 (ORCPT ); Fri, 8 Feb 2019 12:45:58 -0500 Received: by mail-ed1-f66.google.com with SMTP id t6so3450324edw.12; Fri, 08 Feb 2019 09:45:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=VPAIx60fv8TTLxQI5f+txnUSAJApFxWkRXdwiHSG3cg=; b=t7UJ39DYjeycYbXdDVeVsrpvAi34UPA/SMs3H47gNMdpipS4gWsPBnkpRv1h+/EpRS WQ21bJBOVLmv2PbwJHD21IEtP4mgMzqi5Jm8JAUmEQNYG0cDupmWbzsB+VU1SRm0WwwX 9PmLwluhWUizSWZi7POA42lfHG3txAAClDBtnmZcdDv8PoqpqfUy5qNAhVVOvy4zmwqw oD+9Q6miuD7r8pp7vcw94hmOQmhm4BLwuf9PpAgedVtTX6vHLRsqlR0UAz1o46Y5C+kx FompjPdlu+DBmHanOw8uG5MmHS6o49u0WgQhMCLqdZqQFo2MRj1QcDJq16Gq6JPAPl9A I0iw== 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=VPAIx60fv8TTLxQI5f+txnUSAJApFxWkRXdwiHSG3cg=; b=dsidNrRykRGztkgH+emhdjK68prSzelV9SLve/gjMP/FisvWfaqfmTLKhhM/rB/FUW xE7dHjG2IASKQuZTVxt2vdgZvvtxQm86Y3cpK3l81nS1XH8Nc/E8iVhjc6dJxm1OsaPO lSRQtIxyfb4YCJm+k96HKDLfowkczP72SW2uDq62lJP/sySWFU8DudVAuczDD9Vs7SFz /dVPGqHlhrACbK+zupBsfwhPQCFjWR4YR3eFr3wNTzlcDpoUT8k2jiknr+LI74hLazzU ELx7WbYeFyiOrGe0hbF6697WIfC106y0Uf7H/FefJrKFokOVmuJa+NLNDhFpfneL3e7U YblA== X-Gm-Message-State: AHQUAub+8VTMKIsoLQei32HleixZzd0EvxYKd/twt33Nklfg5qtxrsQ6 1z+Gx1m9F2arm8PdGpkj5n0= X-Google-Smtp-Source: AHgI3IbRiFZijyeBx6re2AuyUmg6ziXdUK85x/JFep51TPatSsdnZ3wQxoiCjzaOXmPcie14MRiMOg== X-Received: by 2002:a17:906:4ac2:: with SMTP id u2mr16873967ejt.94.1549647955913; Fri, 08 Feb 2019 09:45:55 -0800 (PST) Received: from archlinux-ryzen ([2a01:4f9:2a:1fae::2]) by smtp.gmail.com with ESMTPSA id l17sm758756edc.56.2019.02.08.09.45.54 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Fri, 08 Feb 2019 09:45:55 -0800 (PST) Date: Fri, 8 Feb 2019 10:45:53 -0700 From: Nathan Chancellor To: Nick Desaulniers Cc: Masahiro Yamada , Michal Marek , Linux Kbuild mailing list , LKML , sedat.dilek@gmail.com Subject: Re: [PATCH 3/4] Makefile: lld: tell clang to use lld Message-ID: <20190208174553.GA14762@archlinux-ryzen> References: <20190207220155.81351-1-ndesaulniers@google.com> <20190207220155.81351-3-ndesaulniers@google.com> <20190208055059.GD9647@archlinux-ryzen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 08, 2019 at 09:27:19AM -0800, Nick Desaulniers wrote: > On Thu, Feb 7, 2019 at 9:51 PM Nathan Chancellor > wrote: > > > > On Thu, Feb 07, 2019 at 02:01:51PM -0800, ndesaulniers@google.com wrote: > > > This is needed because clang doesn't select which linker to use based on > > > $LD but rather -fuse-ld=$(LD). This is problematic especially for > > > cc-ldoption, which checks for linker flag support via invoking the > > > compiler, rather than the linker. > > > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/342 > > > Suggested-by: Nathan Chancellor > > > Signed-off-by: Nick Desaulniers > > > --- > > > Makefile | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/Makefile b/Makefile > > > index 0eae4277206e..6307c17259ea 100644 > > > --- a/Makefile > > > +++ b/Makefile > > > @@ -502,6 +502,9 @@ endif > > > CLANG_FLAGS += -no-integrated-as > > > KBUILD_CFLAGS += $(CLANG_FLAGS) > > > KBUILD_AFLAGS += $(CLANG_FLAGS) > > > +ifneq ($(shell $(LD) --version 2>&1 | head -n 1 | grep LLD),) > > > +CLANG_FLAGS += -fuse-ld=lld > > Sorry, Sedat reports [0] that this is not quite correct; if $(LD) > matches LLD, then we need to set -fuse-ld=$(LD), not -fuse-ld=lld, > since you may have lld installed as lld-7 or lld-8, for example: > https://github.com/ClangBuiltLinux/linux/issues/358 > We'll need to make sure that it is compatible with the way that Clang expects arguments to '-fuse-ld=' because it looks like 'ld.' is automatically appended. https://github.com/llvm/llvm-project/blob/5be3dbdb082ffba4f846e3572ea802d156dd8d34/clang/lib/Driver/ToolChain.cpp#L438-L468 > > > +endif > > > > This section needs to be moved up above KBUILD_CFLAGS otherwise it never > > actually gets passed along. > > > > With that change, please add: > > > > Reviewed-by: Nathan Chancellor > > Tested-by: Nathan Chancellor > > > > > export CLANG_FLAGS > > > endif > > > > > > -- > > > 2.20.1.791.gb4d0f1c61a-goog > > > > > > > -- > Thanks, > ~Nick Desaulniers