From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 89223 invoked by alias); 27 Apr 2017 20:04:22 -0000 Mailing-List: contact gnu-gabi-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: gnu-gabi-owner@sourceware.org Received: (qmail 88695 invoked by uid 89); 27 Apr 2017 20:04:18 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.99.2 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.1 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=ham version=3.3.2 spammy=shipped, H*Ad:U*davidxl, shipping X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=ham version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on sourceware.org X-Spam-Level: X-Spam-User: qpsmtpd, 2 recipients X-HELO: mail-qt0-f182.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=rSERFHoQMjd9WPK+P0XZZhKIgZK/RsfWooZuLKRTTaw=; b=YLKdHV0/s4SOpIdJ+a26pEgXBTVjw5eHSo4yDr4HMjs8j7wd7bqSFYJvepAuIIjdsH vReBSvtM0N/PvLqnoeXhTdMiCasiI+HC0815FfFZLHgqFOdmfGsDPaAUprgQg8/Z7bog twXqHmGYyQRr6/4TrCyg/4H+hXQjG2Puz4tmVJ6P6wINd6RABL9e0PJgZKcv3q1cLJMb pwdsLDqzndga3cPPfizVdVIhvqsaTqOP9wHgoiWdciLG1RD04E85VuUZzDkFT+/c3yDx pYpk0+u4pVI7jTUVXV2M3vd3Nl95st5jGxjIlr60iZqXDCDuFry0J7TGMYeeSK3qtWwr P+Hw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=rSERFHoQMjd9WPK+P0XZZhKIgZK/RsfWooZuLKRTTaw=; b=kCVLVrghM0tWd+xFO/qRfAV+L3fDGFXpJEJ2/CQBVSupEiqEx8s2ZbfFnXVEZegcVb THmPYQucwlapjp7F89cXLZ8VoO2nUtGoP94Glv7iUoBF3zV7FedjTi/HpJKUHBKwF+AK 9BK4NiDSowc4MKKmqWjWPu5eomOwVz5nj34O3Jry+DtIlpUeSVf4PzvW7KM4bVGKC1qI 091WLpj9ewdnkB71jSJcw668plD5zv5wx88s8tjw3YnKmcJitnchxMLc1ItFzI+yEPFG A6Fc/QcdT4P+l5wy+WFH7CkisahIT2b4bD4aqaPCvDuZc+RvzVrLmyHTBcaPH7Q44uHE pSWw== X-Gm-Message-State: AN3rC/7T2jnwFFqjGmdXPMXeUyqYO5//HTX1s3BYKJDpNdlFI4upAKt7 VrIetnsi88HlUJnFmowLepL33vxc1FuZuEs= X-Received: by 10.200.33.152 with SMTP id 24mr6382781qty.38.1493323457087; Thu, 27 Apr 2017 13:04:17 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: =?UTF-8?Q?Rafael_Esp=C3=ADndola?= Date: Sun, 01 Jan 2017 00:00:00 -0000 Message-ID: Subject: Re: Reducing code size of Position Independent Executables (PIE) by shrinking the size of dynamic relocations section To: Sriraman Tallam Cc: gnu-gabi@sourceware.org, binutils , Xinliang David Li , Cary Coutant , Sterling Augustine , Paul Pluzhnikov , Ian Lance Taylor , "H.J. Lu" , Rahul Chaudhry , Luis Lozano , Peter Collingbourne , Rui Ueyama Content-Type: text/plain; charset=UTF-8 X-SW-Source: 2017-q2/txt/msg00007.txt.bz2 On 25 April 2017 at 13:12, Sriraman Tallam wrote: > We identified a problem with PIE executables, more than 5% code size > bloat compared to non-PIE and we have a few proposals to reduce the > bloat. Please take a look and let us know what you think. Just a bit of terminology, it is not code, it is a read only data. Why is the table size a problem? I can imagine a few reasons, but it would be nice to know which one you are trying to solve: * The file size itself is a problem for shipping the file. * The startup time is a problem and a compact table makes the dynamic linker faster. * The memory usage is a problem. For the last one one thing that could be done is have something like PT_GNU_RELRO but that tells the dynamic linker to unmmap the region completely once it is done with the relocations. In addition what is done for COFF, the other existing solution I know is https://wiki.mozilla.org/Elfhack. In the case of mozilla the issue was just the size of the binary being shipped I think. Cheers, Rafael