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=-11.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 9A122C433DF for ; Sun, 16 Aug 2020 12:14:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74F9E207FB for ; Sun, 16 Aug 2020 12:14:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="tVKZPu4R" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726715AbgHPMOY (ORCPT ); Sun, 16 Aug 2020 08:14:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726389AbgHPMOQ (ORCPT ); Sun, 16 Aug 2020 08:14:16 -0400 Received: from mail-oi1-x241.google.com (mail-oi1-x241.google.com [IPv6:2607:f8b0:4864:20::241]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8446AC061786 for ; Sun, 16 Aug 2020 05:14:16 -0700 (PDT) Received: by mail-oi1-x241.google.com with SMTP id b22so12398709oic.8 for ; Sun, 16 Aug 2020 05:14:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:reply-to:from:date:message-id:subject:to:cc; bh=dePSLKsu+YCWcQIX7wvlYCR7MFq4XN12gBiIPCD2giI=; b=tVKZPu4RGZCM733zT3krVxSaJ/kBBLGHF54lzQH9Bt2FEsQJ46AW0UXtBFgzUhLFL0 RroznuIjAtMTbMcqrJoJ2dSuSGD9CBrAVjAHnCUUUGin7sUgvQm2qZjYcqx8Ac5kG1qh kAPo8Nke8hzqXcGgl+SkdBDNfkTcO8ieR6uqMI0laOMvXaB9a8tyYAjGsDm9lPHpB5Xg ciaYGDzUMGz/vTrEO2Ntq0tV4flXCIzV1eNeN4+u5Y2n38wgLqcx0Sfvo3xC77AQtzTV dZk1Hp00Zaj2Zj2bNmjxMQJ9CUQk8YuBnoWYToSpQeZycsmyPA/JhEmFLpWqWWvyfJay IWMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:reply-to:from:date:message-id :subject:to:cc; bh=dePSLKsu+YCWcQIX7wvlYCR7MFq4XN12gBiIPCD2giI=; b=pWUvInGtz9268lmUAN//4pUaYPuPGCNeLTt2eZ6/wTcdI/2vtd9MQOICrYPb7FvwDr 8Apj2pnq+IcLgG18F+PpT6tuMRjTdKuvezr4vksJEx+VunvE+rSMy8kcvDMzYDebtRZB o5s4pR5CANOxYb8tv2c+Xo1Ds2sFkzWzlVljEzqlmDGLJv/fdbrInW23WWwi16u1Z3mv T0h0axVnGOSdlB++6uPo0tb394PFF05iqoYNnjj0TGb8zzFum5CCyt1F8QViOkhYoyWK a6PGCqZ9lgpNYbFni34tzyTqyxgF5NmymSEVCvngz+cC9g8PWpMY5+X/PPQI9kuhjmAQ etBQ== X-Gm-Message-State: AOAM530UnjARnC54Atu3GeS5dsGhTtPKmVN3Z7aY5gIVgOxSKzrwP5eM BYoPot+lL1ZzyFdv0sg4yMk7ySdQj0yMy8QlsOU= X-Google-Smtp-Source: ABdhPJyhqzxAkY+SdMO6hzC8zvEmTamAcDzA4anBm6gwobGMn5WpKkk/tiWSRxjOKFkgJKoudG+4o0Wc5+nv4cGeDjU= X-Received: by 2002:a05:6808:311:: with SMTP id i17mr6903127oie.72.1597580055929; Sun, 16 Aug 2020 05:14:15 -0700 (PDT) MIME-Version: 1.0 Reply-To: sedat.dilek@gmail.com From: Sedat Dilek Date: Sun, 16 Aug 2020 14:14:04 +0200 Message-ID: Subject: Introduce CONFIG_DEBUG_INFO_AS_DWARF2 and CONFIG_DEBUG_INFO_AS_DWARF4 To: Masahiro Yamada Cc: linux-kbuild@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Hi Masahiro, I wondered why my generated linux-image-db Debian packages were so big when I use GCC toolchain instead of LLVM toolchain. It turned out I mixed both... KBUILD_AFLAGS += -Wa,-gdwarf-2 ...together with... DEBUG_CFLAGS += -gdwarf-4 ...when CONFIG_DEBUG_INFO_DWARF4=y is set. So I hacked up something like the following to prevent this: diff --git a/Makefile b/Makefile index 24a4c1b97bb0..e7a8e47b0e34 100644 --- a/Makefile +++ b/Makefile @@ -815,7 +815,11 @@ DEBUG_CFLAGS += -gsplit-dwarf else DEBUG_CFLAGS += -g endif +ifdef CONFIG_DEBUG_INFO_AS_DWARF2 KBUILD_AFLAGS += -Wa,-gdwarf-2 +else ifdef CONFIG_DEBUG_INFO_AS_DWARF4 +KBUILD_AFLAGS += -Wa,-gdwarf-4 +endif endif ifdef CONFIG_DEBUG_INFO_DWARF4 DEBUG_CFLAGS += -gdwarf-4 diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9ad9210d70a1..9f11fc71462c 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -257,10 +257,23 @@ config DEBUG_INFO_SPLIT to know about the .dwo files and include them. Incompatible with older versions of ccache. +config DEBUG_INFO_AS_DWARF2 + bool "Use DWARF-2 assembler option with debuginfo" + depends on $(cc-option,-Wa$(comma)-gdwarf-2) + help + Set DWARF-2 assembler option with debuginfo + +config DEBUG_INFO_AS_DWARF4 + bool "Use DWARF-4 assembler option with debuginfo" + depends on $(cc-option,-Wa$(comma)-gdwarf-4) + help + Set DWARF-4 assembler option with debuginfo + config DEBUG_INFO_DWARF4 bool "Generate dwarf4 debuginfo" depends on DEBUG_INFO depends on $(cc-option,-gdwarf-4) + select DEBUG_INFO_AS_DWARF4 help Generate dwarf4 debug info. This requires recent versions of gcc and gdb. It makes the debug information larger. NOTE: This is on top of Linux v5.8 vanilla. NOTE-2: When building with LLVM toolchain v11.0.0-rc1+ and especially with LLVM_IAS=1 (and LLVM=1) DWARF version 4 is a good choice. For details see below links. Thoughts? Regards, - Sedat - [1] https://github.com/ClangBuiltLinux/linux/issues/1086 [2] https://github.com/ClangBuiltLinux/linux/issues/1086#issuecomment-674503335 [3] https://github.com/ClangBuiltLinux/linux/issues/1086#issuecomment-674517876