From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by sourceware.org (Postfix) with ESMTPS id 281753858431 for ; Fri, 29 Oct 2021 18:21:41 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 281753858431 Received: from mail-qv1-f71.google.com (mail-qv1-f71.google.com [209.85.219.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-339-jM3Mg1W3NDagmmrRs9loGw-1; Fri, 29 Oct 2021 14:21:36 -0400 X-MC-Unique: jM3Mg1W3NDagmmrRs9loGw-1 Received: by mail-qv1-f71.google.com with SMTP id kj30-20020a056214529e00b00398ec9793a8so1583297qvb.4 for ; Fri, 29 Oct 2021 11:21:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=Z8/tXjTjKrCdXikbBtl69BDncx56crbF9cOd+8cDVA4=; b=utjBUWJ8DKVg5MEvrhz1Y8UbQSwnwln06xpzqv8ggOWIEg18pH/yfPzklx4IfYkYyX cKVOM9blj71zJdATrzkXRHtCxWZairMNrHVFLjfZTRk+7vc1rEpz7+lImQJz+Wmcw4mQ O9W7+0B8wPcZvozNFDHIVRg9j6OQtCJJST2YrexZrkMvxZglGDkpA5owlQHVp6qg9mIy BMUACmOMhrJIhx39AnZ2cKy6biqEgfK3oqvKRnm3D5qbXURNwfQiG+iHETpGQ33WWuT9 Nt5e4mwX9QnbrCK4ng+xEI/CktwfNEZRVHqIVhWdVEUrgOQ/Vz7twNcdjv1FaEdj7tJe A6AQ== X-Gm-Message-State: AOAM530n5vJkyYixOHqmOcf6NqTq0f0I3GF2ugcjtFFKidNpt0J9DCvK vTUvNfqtkfPMw8/jwORvtRSY5aHP3Q4a3i/uqhk/zGpB4zDLAN1qI3qgAAT4bHn8AhohOt9GU4C HnWaVNOTVnrkvh1nr2f8z X-Received: by 2002:a37:2705:: with SMTP id n5mr10146719qkn.127.1635531695589; Fri, 29 Oct 2021 11:21:35 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxwfLDTeLWKmu5/iVk95FXPSjn560FNIrHL/Z1TeV76DlNf6hw5m0ILlntKG0vNfuCIL1+otg== X-Received: by 2002:a37:2705:: with SMTP id n5mr10146700qkn.127.1635531695311; Fri, 29 Oct 2021 11:21:35 -0700 (PDT) Received: from [192.168.1.16] (198-84-214-74.cpe.teksavvy.com. [198.84.214.74]) by smtp.gmail.com with ESMTPSA id t4sm4847430qkp.42.2021.10.29.11.21.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 29 Oct 2021 11:21:34 -0700 (PDT) Message-ID: <1763c6f4-dfb9-e102-84d6-892ee2a3208a@redhat.com> Date: Fri, 29 Oct 2021 14:21:33 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [PATCH v2] elf: Support DT_RELR relative relocation format [BZ #27924] To: Fangrui Song , libc-alpha@sourceware.org Cc: binutils@sourceware.org References: <20211017005020.2645717-1-maskray@google.com> From: Carlos O'Donell Organization: Red Hat In-Reply-To: <20211017005020.2645717-1-maskray@google.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=unavailable autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Oct 2021 18:21:42 -0000 On 10/16/21 20:50, Fangrui Song via Binutils wrote: > PIE and shared objects usually have many relative relocations. In > 2017/2018, SHT_RELR/DT_RELR was proposed on > https://groups.google.com/g/generic-abi/c/bX460iggiKg/m/GxjM0L-PBAAJ > ("Proposal for a new section type SHT_RELR") and is a pre-standard. RELR > usually takes 3% or smaller space than R_*_RELATIVE relocations. The > virtual memory size of a mostly statically linked PIE is typically 5~10% > smaller. We've been going over this patch on the weekly Monday patch queue review. I took a note to point out that one of the blockers here is that it is difficult to immediately test this work because it requires a working glibc build using ldd (which has support for DT_RELR). What is the status of the lld support patches for glibc? If we made progress on the lld support then we'd be able to more easily review a testable configuration and keep the review going forward. -- Cheers, Carlos.