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=-13.3 required=3.0 tests=BAYES_00,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 B89D3C4361B for ; Thu, 3 Dec 2020 22:57:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 639AA22482 for ; Thu, 3 Dec 2020 22:57:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731904AbgLCW5g (ORCPT ); Thu, 3 Dec 2020 17:57:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728606AbgLCW5g (ORCPT ); Thu, 3 Dec 2020 17:57:36 -0500 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A041C061A51 for ; Thu, 3 Dec 2020 14:56:56 -0800 (PST) Received: by mail-pl1-x643.google.com with SMTP id j1so2020810pld.3 for ; Thu, 03 Dec 2020 14:56:56 -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=EHAYrKbj/zPl1+pVBO2mTUTD59eSt3ugUwhIW8vCe/M=; b=ovTruuoqCEsd5W5/yRX9B6q1dnWkeOHgHxocdVVbWfkA3R605oK/EWYMKEVL8CI5EO HUYQcNF0XWX4gYmPHzITxzP6Ow3StkrjkbcWocMtTHrdnGKfCziCOhHCoI2xzgubaOA6 OQiN99aPdqBWZkfavhfdXtcqrJokKEJ+UxvjvI5EMgfMxZvHW2wkJUl8+cFvoX84Bijc HqEAJsDWhSF4RFtMUkHO+Zlo9Bm0PzHfwUHj0oPE1yE7VMTzQ1RuFgpwMUfBbL5J+n2w xWUTKTDJgAzxwXdvRSgZOhZ+9zIaPiWDSQPgo++wRTMmbZKzYhw8Wx8ktgyoONFgFdW5 +Ocg== 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=EHAYrKbj/zPl1+pVBO2mTUTD59eSt3ugUwhIW8vCe/M=; b=XGM5unFd1c94yBvmvlSfFmF3xeGnwlzWIcgPibC38mRfjo2MGossGUMpQldvJ8mvVa AzO2krb/4u9g2bValzn8Y5sZHRS8yC+mtdPmBAb7oShehoBhdLucx910ZhjJIGLkyQVp ClzNXjoTNnYCgMeBOasVfzMFOGJ66Mt8H8VNAtmq1YvlBspXNH1sMMVILThwi3s+K/1D Dmq0dSamvRwVVZou58bxVsvk1VsDYrjpzndssLCXlEcCc69CoaFsRGfgdDrDkDrJner/ NLUQXFNzXM3Uz1DUDE1+mpedDyBB2D5ktuES+QKHla0AMRIHFc5nrTcrUqluTTkqoooo enyA== X-Gm-Message-State: AOAM532nvHPpO4U9lOaxfe8j5788wbpVpMTWPceZOEEoe2HQ6tQF/8HT 9i/Kl/qX6CyObvI9JPVOr15lqGYsCbT0AjSybc9BQQ== X-Google-Smtp-Source: ABdhPJzbOJ8AkzQrZ1pmet6hcC3Amko/IKkWSx77hmaWe06U2WVabo59psGy4ODZ38M2QGHs888LYCI4one4nnVU36Y= X-Received: by 2002:a17:902:e901:b029:d8:e727:2595 with SMTP id k1-20020a170902e901b02900d8e7272595mr1164945pld.56.1607036215507; Thu, 03 Dec 2020 14:56:55 -0800 (PST) MIME-Version: 1.0 References: <20201022012106.1875129-1-ndesaulniers@google.com> <20201104000016.GA2399651@rani.riverdale.lan> <20201104001703.GA2407187@rani.riverdale.lan> In-Reply-To: <20201104001703.GA2407187@rani.riverdale.lan> From: Nick Desaulniers Date: Thu, 3 Dec 2020 14:56:43 -0800 Message-ID: Subject: Re: [PATCH] Kbuild: implement support for DWARF5 To: Arvind Sankar Cc: Masahiro Yamada , Linux Kbuild mailing list , LKML , clang-built-linux , linux-toolchains@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 3, 2020 at 4:17 PM Arvind Sankar wrote: > > On Tue, Nov 03, 2020 at 04:05:36PM -0800, Nick Desaulniers wrote: > > On Tue, Nov 3, 2020 at 4:00 PM Arvind Sankar wrote: > > > > > > On Wed, Oct 21, 2020 at 06:21:06PM -0700, Nick Desaulniers wrote: > > > > Further -gdwarf-X where X is an unsupported value doesn't > > > > produce an error in $(CC). > > > > > > Do you have more details here? On godbolt.org, gcc does report an error > > > for unsupported dwarf versions. > > > > > > https://godbolt.org/z/G35798 > > > > > > gcc does not seem to pass the -gdwarf-* options to the assembler when > > > compiling C source. For assembler, gcc will pass an appropriate option > > > depending on the version of binutils it was configured with: if the > > > assembler doesn't support dwarf-5 it can call it with --gdwarf2 for eg. > > > > > > If the user is using a properly configured toolchain it doesn't look > > > like it should be an issue to just use cc-option? > > > > I wrote the base patch back in May, and didn't revisit until recently. > > I could have sworn the cc-option silently failed for the check > > cc-option does, which is /dev/null input. I need to recheck that, but > > it doesn't hurt to simply include it for now, which I've done in a v2 > > I'm about to send. > > -- > > Thanks, > > ~Nick Desaulniers > > This is giving me deja vu about the -gz=zlib option. > > Didn't Masahiro fix the cc-option issue with > 4d0831e8a029 ("kconfig: unify cc-option and as-option") > > The existing -Wa,-gdwarf-2 in the Makefile seems bogus, btw. GCC 4.9.0 > at least appears to pass on --gdwarf2 automatically. It looks like we don't need -Wa,-gdwarf-2 when -gdwarf-2 is set. So I can probably drop +DEBUG_CFLAGS += $(dwarf-aflag) from v2. Will retest though. -- Thanks, ~Nick Desaulniers