From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10olkn2014.outbound.protection.outlook.com [40.92.42.14]) by sourceware.org (Postfix) with ESMTPS id 315B7385841A for ; Sun, 26 Mar 2023 16:00:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 315B7385841A Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=maskray.me Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=maskray.me ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=jYHh+45Bi6Ub+mi1wIouPzWHNPISTmp1CC2jwzUe6wi06kWIFenbguj2ZZ9PhG2NdsI22rgAiEvyV9VSULsjgXilnwNWLRLRhDv8atzDfcy0Il1CcmdsxU1jQ7DqUStWAw0gHjcFzfo0C7VB3fVByV8SyW+dZmLDGCk4tYnbZmM4+CGl4B+1mwbDneZtyeWH6LGfWjeQ/ccZSJVTOxa4Z5DrSLFRvolrl1NPpS61duGrUdplE8N+dk/p5Eeh4JJKs29CwjJkckPWHZ2QU4+aaOWfdn8I7slgrBHq4J57bVOf59WeU9C/f16yuHf30Ycp9VnV23hoEoCuFh+i79lytA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=b+/eCi9VOMkTCrt2erUFgt/kWU6Neo0tA34sdG6N9dc=; b=M9gl86q5hgDu0kR8RbAxH469xhv3LVVKJSFjug1alL01p982VvLcpOfWby08uxPWRUlLBn1dKBYKJAh4MB0lsqhlsAm3RVFWm3L5K8m12xdVXzpi7bDfqwjMOAb6ItwbDNi6d2W3k9gR8veEbl8oKIkG1LUWzpA0cWf1LojoDbnYjbe1MhtvD0OiMwaAbP3WQm/3YPtORv6MyToqC+S0XJN9L2FhzahJSWxVd/v/zDyUq/P6GkUK0tI1jtVyAX200ffQ4+9pVaf8ef1DANh+FFjdt2AydI+Hpt8fGKPpNT+/0zLBY1c5+VVhFhOUcZiw+qvI9RHD0MWkvlU87e+xDg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none Received: from DS7PR12MB5765.namprd12.prod.outlook.com (2603:10b6:8:74::19) by DS7PR12MB5959.namprd12.prod.outlook.com (2603:10b6:8:7e::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6178.41; Sun, 26 Mar 2023 16:00:30 +0000 Received: from DS7PR12MB5765.namprd12.prod.outlook.com ([fe80::b084:b37b:f2a8:78d9]) by DS7PR12MB5765.namprd12.prod.outlook.com ([fe80::b084:b37b:f2a8:78d9%2]) with mapi id 15.20.6178.038; Sun, 26 Mar 2023 16:00:30 +0000 X-Gm-Message-State: AAQBX9e2ivNDluNMhGOCi5NN0Yfi2D4OyrrF3KlvsexsOm5ETslykjq+ a924zXm9g5+xXwdTle6hCPX9C9djxi66c3Wt1iA= X-Google-Smtp-Source: AKy350YEOOV9K482aKgru6yF/EOQEcDZijwJ4IL+vufaM4G71WJ3n5qMJH3XUsj5zyBWf8ayAGMnHCT7adUP1itLw+I= X-Received: by 2002:a17:90a:ff13:b0:23d:30a:692b with SMTP id ce19-20020a17090aff1300b0023d030a692bmr2561623pjb.4.1679846092337; Sun, 26 Mar 2023 08:54:52 -0700 (PDT) References: In-Reply-To: From: Fangrui Song Date: Sun, 26 Mar 2023 08:54:41 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: Compressed debug information To: Tom Kacvinsky Cc: Binutils Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-TMN: [eoPH+CrFvcjW0eA7kyy2TzSzshueJrio] X-ClientProxiedBy: BN9P223CA0010.NAMP223.PROD.OUTLOOK.COM (2603:10b6:408:10b::15) To DS7PR12MB5765.namprd12.prod.outlook.com (2603:10b6:8:74::19) X-Microsoft-Original-Message-ID: MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB5765:EE_|DS7PR12MB5959:EE_ X-MS-Office365-Filtering-Correlation-Id: 23e7bea0-5385-4c81-d3e7-08db2e133927 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?Z2NKeldvaWFDclRzazJ5eUhVSjNwMHdNQllhNXU4RWtaMjkrL0pRQ2ZWR3Jq?= =?utf-8?B?WWFPQnJVdzM0V0VOcDBiTml4dXMvRXVvbE0xT3FsdlU2VHhuNW9ySUFLczVF?= =?utf-8?B?QWtVSlRXUGNlUTV4ZkhuKzN2cENFYVRybzIxTVhwUDhtblllaFhSS3EwK3JP?= =?utf-8?B?cDkwRXYwZ29mOTdjL2pDZHN4MXQySnRhYWZEMmdIcXlIV1BqdVpERVZnSm9B?= =?utf-8?B?R1JzdmM1R29KQWZWMzFUblNkZ3ljcXdRRSs2MUNzN2pUQUZ2STc0YkVLSlRo?= =?utf-8?B?WFhFU2dEOWoyYkNUNEZNV210ekF5eFB2d0ZpYXlvVm9pSStHRnJTOTBRNUI3?= =?utf-8?B?ZkNsRGhhMmhWdWhVbFQ1WUowdUtvR1lFc3plSS9lVm1nSlQ3VTQxTDIxN05v?= =?utf-8?B?MU9RTGpSYUU3cGlyanJWNnE3MFNGdkMrOUVzVituTlhoUnFZRDFzSGk4ZmFH?= =?utf-8?B?aWhTM0VGTFB1TEtwdkdMZDNIMXVjR0pGcWZGY1JKQk9GSndqQ0grai84NTFn?= =?utf-8?B?TzdYNmE5alcxd3RwVDR2MEFVTlRBcmlGVkdaclYwSWlnWkR6cTJiT3NqeXMz?= =?utf-8?B?U1hXS2tRRFIrM2ZvYnAydW9pRUdBM0w5bHBhUVVYOVpZNDJqQ3AvRmE3WWFh?= =?utf-8?B?WDRtZTdWdnhZb0RaQzFhY1Vxa3RlWXFzczg5YTFCWFpia09hbXZodGZGc2tv?= =?utf-8?B?WHhkUkpoVjh5cnkyZWxCOVN2MjkyVnYrQW5Ha3RMZWhGcXA3K2t1VFg2Z3F4?= =?utf-8?B?dzZLdFlyUXN4NE53bGNxRFAybTFvR0RQUFJKMjJHZlRoMWNSSkJncXJBWldM?= =?utf-8?B?OE0xSTBDVWZrb1JxQ1NkZHB2T3FuUTdibFFQalNNZWRCRDFKaE5FcGliNFZJ?= =?utf-8?B?NmdNT2FpTzBvY0FjOW40THVhYzJ2M3BBU2J5cXA0UnUrUjdCY2swNGxsNlFY?= =?utf-8?B?YlZRNFBvSWhQK3VIMmpOMVFqNkhUVFQzUWpPWUZaWkRVZENSZklNMFRNbzF0?= =?utf-8?B?TEsvdjlFb2NIN0tCOXBoU05EcFNwTVk0UXNVaGNPck5NK0NFcWF2MG9BUVpw?= =?utf-8?B?YUZudHRrUGZSUkUzQUVUMjI5RjdqRE9PWFZOK1duOVJCeDEvRkdWaFpWNFF1?= =?utf-8?B?U0w1QlBFeXlxVUlLQmpEUndFYTNObkZEemRSeHJFWHpvYzdFRDVac1NOcWU3?= =?utf-8?B?M3hobjVWbDRlczYyVkZlZ25NQ3gzUHVwMWFPbWV4MXhKQURjdWNudFZzOFgr?= =?utf-8?B?V3BFeGxUSDlUZVFoTmRVbkZHVjVTNEdEWnlHOHFhTjJHQ3NGN0pSWkd4ZDNJ?= =?utf-8?B?Zi9uWHhKeHBYRVhVUXlFWmNTdWFqSms1RkMwREtIcVBDdTEvSTNwd0pnZTN0?= =?utf-8?B?WktVMVJteEl1OVhXeU1lc3NVY2V6WmdiTDltRkpVYTlMRU1UMEhGTm9vM2dY?= =?utf-8?B?MlZHRU1aVUV0NnpvbS9YckM1Z24xcys1SHJnRzIvRWk3bDNqeDBQL3lWZnJ0?= =?utf-8?B?Z0hWYjZHTTJFcEY4NkpPZEtFbHd4b1NaUFdjNGJjbDE5VFhOZXZOUlBqV2JT?= =?utf-8?Q?MKoOgG3nvEcqfylkIsDzrHUL/1VEEFjOYnU0c3LhKpkYkK?= X-OriginatorOrg: sct-15-20-4755-11-msonline-outlook-71ea3.templateTenant X-MS-Exchange-CrossTenant-Network-Message-Id: 23e7bea0-5385-4c81-d3e7-08db2e133927 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB5765.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Mar 2023 16:00:30.3880 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB5959 X-Spam-Status: No, score=-3.0 required=5.0 tests=BAYES_00,KAM_DMARC_STATUS,KAM_INFOUSMEBIZ,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Sun, Mar 26, 2023 at 8:29=E2=80=AFAM Tom Kacvinsky via Binutils wrote: > > Hi again, > > On Sun, Mar 26, 2023 at 10:21=E2=80=AFAM Tom Kacvinsky wrote: > > > HI, > > > > I have a question about compressed debug sections. I think I am > > getting compressed debug sections because a build of our product > > with -gz=3Dnone (using GCC 12.1) results in larger artifacts than a > > build without -gz=3Dnone. Moreover, if I use ld.lld for the linker, wh= ere > > I built LLVM without zlib support, it complains that the object files w= ere > > ELF_COMPRESSED and ld.lld could not handle them because LLVM > > was built with zlib support. > > > > Because of that I am under the impression that the compressed debug > > section object files fed into the linker result in compressed debug > > sections > > in the final shared library or executable, provided the linker can hand= le > > compressed debug sections. > > > > But I don't know how to verify that the final debug section(s) in the > > executables/shared libraries have debug information. Google was not my > > friend with respect to determining that. I looked at readelf and > > objdump options (from binutils 2.39) and didn't see an option for that.= I > > also looked at dwarfdump output but didn't see anything. > > > > Any hints? > > > > > I'd like to retract this idiotic question of mine. Turns out that no, > there was > no compressed debug data. I compared -gz=3Dnone and against a build w/o > -gz=3Dnone and the sizes were the same. Then I built with -gz=3Dzlib and= the > file sizes then changed. > > So I found my answer by experimentation. Now I am going to see what I > can do to get this information using tools like readelf or dwarfdump. > > Tom Hi, Tom, you can use readelf -S or readelf -t to check whether an object file has compressed debug sections. % readelf -S a.o ... Section Headers: [Nr] Name Type Address Off Size ES Flg Lk Inf Al ... [ 5] .debug_abbrev PROGBITS 0000000000000000 000080 000087 00 C 0 0 8 % readelf -t a.o ... Section Headers: [Nr] Name Type Address Off Size ES Lk Inf Al Flags ... [ 5] .debug_abbrev PROGBITS 0000000000000000 000080 000087 00 0 0 8 [0000000000000800]: COMPRESSED ZLIB, 0000000000000093, 1 I have just added the information to my blog post: https://maskray.me/blog/2022-01-23-compressed-debug-sections