From patchwork Fri Jan 29 19:43:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 12056421 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 145C8C433E6 for ; Fri, 29 Jan 2021 19:44:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC92164E11 for ; Fri, 29 Jan 2021 19:44:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232733AbhA2ToK (ORCPT ); Fri, 29 Jan 2021 14:44:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231533AbhA2ToF (ORCPT ); Fri, 29 Jan 2021 14:44:05 -0500 Received: from mail-qk1-x74a.google.com (mail-qk1-x74a.google.com [IPv6:2607:f8b0:4864:20::74a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2BC7C061573 for ; Fri, 29 Jan 2021 11:43:24 -0800 (PST) Received: by mail-qk1-x74a.google.com with SMTP id u66so7949844qkd.13 for ; Fri, 29 Jan 2021 11:43:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=3SeeNcVsK2P/XlQ94PAyrrJlSF2nsUa9roDX0u/Qyk0=; b=n3LuAM9o8mgd/+DA1a0GIDX9oPnXPqpqvuILu/cChVKUM5teGNlfcTzEVlTXavzk+O 8YcSVrE7+bxZ6PILpHDWg6kJf7KCcGUdp4L4ta9a4xYccVAlVrKzEclQDccBMJBkIz2+ CtVem1uB6hI1pJF679uQmTboCuR5WGgTFwAT8eZ56rRifzWHxznMwua1Sm9j6YJDqo47 0W7DbwDIBijstkONoVDUIZ7ISZHpvrxHbcaRuhPsAEk/FPQAEy2L7WzmZTQnINPMppDp P5CYEX993wZY678AsoxOAO/1PFzw5/GmAbKKpXReq0QgsK9bjrmgot1fOJ//BvzcUkA/ DkRw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=3SeeNcVsK2P/XlQ94PAyrrJlSF2nsUa9roDX0u/Qyk0=; b=r+F8yANQS1RID2pZHBBrt9xzZmvbMiePUj2BIIZixR8v9gcBjwQlXoW/GtHdVT/emD oL5Hv3urPJZiPwJeQAU4N11+vPpKLliOrClkUYYh05YjmwjgJkg4dihq7O+3Z54YBTi1 Fxz7whX5f1thjZbyXF5CfVXefgsUJLz5Ov+bDeLz6PJn+FrBdTaDU9Jset/nroHo4Gco RGnZUEeOBAYhKNG/56du+iHh8H/hCO817DjY0DrMaVCt61VkH+VgEG8J9lLjkCoiiWcq QXGMv79QZv3vBLYrJpYPu0Ww6MV6cW26UvNdS8wWTFVtxnd6IS6zPEjlIqCzFqtNMx7a LHAQ== X-Gm-Message-State: AOAM532wbOcBNAxeFlbIup6F1vvaeQ7D7AIIa6CO6BOgZJ7KpdQtAalc SejR0+NM56OYeHKNYpg6Z1MODdURhra+4nt1Glc= X-Google-Smtp-Source: ABdhPJzmLTyrTl81fsKySXCx+7Nn8/qZl7i0MRMwGNomzVPxL7QV+uEFKsqAvuafgWtjkVaMFJt51l4xcH65WGPrM1Y= Sender: "ndesaulniers via sendgmr" X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:4d25]) (user=ndesaulniers job=sendgmr) by 2002:a05:6214:186b:: with SMTP id eh11mr5646289qvb.30.1611949403920; Fri, 29 Jan 2021 11:43:23 -0800 (PST) Date: Fri, 29 Jan 2021 11:43:16 -0800 Message-Id: <20210129194318.2125748-1-ndesaulniers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.365.g02bc693789-goog Subject: [PATCH v6 0/2] Kbuild: DWARF v5 support From: Nick Desaulniers To: Masahiro Yamada Cc: Nathan Chancellor , Andrew Morton , Sedat Dilek , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org, linux-arch@vger.kernel.org, Jakub Jelinek , Fangrui Song , Caroline Tice , Nick Clifton , Yonghong Song , Jiri Olsa , Andrii Nakryiko , Arnaldo Carvalho de Melo , Nick Desaulniers Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org DWARF v5 is the latest standard of the DWARF debug info format. DWARF5 wins significantly in terms of size and especially so when mixed with compression (CONFIG_DEBUG_INFO_COMPRESSED). Link: http://www.dwarfstd.org/doc/DWARF5.pdf Patch 1 is a cleanup that lays the ground work and isn't DWARF v5 specific. Patch 2 implements Kconfig and Kbuild support for DWARFv5. Changes from v5: * Drop previous patch 1, it has been accepted into kbuild: https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/commit/?h=kbuild&id=3f4d8ce271c7082be75bacbcbd2048aa78ce2b44 * Trying to set -Wa,-gdwarf-4 in the earlier patch was the source of additional complexity. Drop it that part of the patch. We can revisit clang without the integrated assembler setting -Wa,-gdwarf-4 later. That is a separate problem from generally supporting DWARF v5. * Rework the final patch for clang without the integrated assembler. -Wa,-gdwarf-5 is required for DWARF5 in that case otherwise GAS will not accept the assembler directives clang produces from C code when generating asm. Changes from v4: * drop set -e from script as per Nathan. * add dependency on !CONFIG_DEBUG_INFO_BTF for DWARF v5 as per Sedat. * Move LLVM_IAS=1 complexity from patch 2 to patch 3 as per Arvind and Masahiro. Sorry it took me a few tries to understand the point (I might still not), but it looks much cleaner this way. Sorry Nathan, I did not carry forward your previous reviews as a result, but I would appreciate if you could look again. * Add Nathan's reviewed by tag to patch 1. * Reword commit message for patch 3 to mention LLVM_IAS=1 and -gdwarf-5 binutils addition later, and BTF issue. * I still happen to see a pahole related error spew for the combination of: * LLVM=1 * LLVM_IAS=1 * CONFIG_DEBUG_INFO_DWARF4 * CONFIG_DEBUG_INFO_BTF Though they're non-fatal to the build. I'm not sure yet why removing any one of the above prevents the warning spew. Maybe we'll need a v6. Changes from v3: Changes as per Arvind: * only add -Wa,-gdwarf-5 for (LLVM=1|CC=clang)+LLVM_IAS=0 builds. * add -gdwarf-5 to Kconfig shell script. * only run Kconfig shell script for Clang. Apologies to Sedat and Nathan; I appreciate previous testing/review, but I did no carry forward your Tested-by and Reviewed-by tags, as the patches have changed too much IMO. Changes from v2: * Drop two of the earlier patches that have been accepted already. * Add measurements with GCC 10.2 to commit message. * Update help text as per Arvind with help from Caroline. * Improve case/wording between DWARF Versions as per Masahiro. Changes from the RFC: * split patch in 3 patch series, include Fangrui's patch, too. * prefer `DWARF vX` format, as per Fangrui. * use spaces between assignment in Makefile as per Masahiro. * simplify setting dwarf-version-y as per Masahiro. * indent `prompt` in Kconfig change as per Masahiro. * remove explicit default in Kconfig as per Masahiro. * add comments to test_dwarf5_support.sh. * change echo in test_dwarf5_support.sh as per Masahiro. * remove -u from test_dwarf5_support.sh as per Masahiro. * add a -gdwarf-5 cc-option check to Kconfig as per Jakub. Nick Desaulniers (2): Kbuild: make DWARF version a choice Kbuild: implement support for DWARF v5 Makefile | 16 ++++++++++-- include/asm-generic/vmlinux.lds.h | 6 ++++- lib/Kconfig.debug | 41 ++++++++++++++++++++++++++----- scripts/test_dwarf5_support.sh | 8 ++++++ 4 files changed, 62 insertions(+), 9 deletions(-) create mode 100755 scripts/test_dwarf5_support.sh