From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 116862 invoked by alias); 11 May 2017 17:09:36 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 116307 invoked by uid 89); 11 May 2017 17:09:35 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.6 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=no version=3.3.2 spammy=H*f:sk:czMaAo9, H*f:sk:591431A, H*f:JU_ECHjOD_, HX-Received:10.55.197.92 X-Spam-User: qpsmtpd, 2 recipients X-HELO: mail-qk0-f196.google.com 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=zZaNea7zaFok833i/uzscFp5xGqaAw1l5+dWuidlDos=; b=fHZMEBYEQOgdFUU8H3icmbEJeUyXhbqUfyho88nI5Y83UeoM7P/WRCCfjZJqmcNG3W ZsgmMXxtwHaazi3gM7Oqmu/NqX2BpNuCT1YSwLgO1EDsP6rX6uWoR+KRfw8ZMObO5Z3p HToqaeFMW9GeR3YO7GCWGXR1KAPA8TIofY4QCSjgNSucJquvX6LrHdlz1VGtuC52se2x 4ymBCWxKzzs7OsWFe9jtcOBgWJz5nRZ+8STVn7b6qQComhpaXfoBHnxJwm3yp1jruZhv kMYlUnEQELi+TSXFEf5/EBc+pUPTsMB6stE8byr4CRiAvsG2jY1jRQTQodkKH3bzIjyy HY3g== X-Gm-Message-State: AODbwcCLMkhMKNZ8jUXodouEFmBOos7MX5kCZJdEgW8Zz6yYE/4lF87i MtxHdEZhzum1iO3oufde0Z+JZEOwPw== X-Received: by 10.55.197.92 with SMTP id p89mr198256qki.34.1494522575366; Thu, 11 May 2017 10:09:35 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <9b8e44de-2fc0-4946-89d7-01c4528d7518@redhat.com> References: <20170508202153.GA28618@intel.com> <146b87ef-0c8c-c829-18e1-41db38df5fd1@redhat.com> <591431AE.6000201@arm.com> <9b8e44de-2fc0-4946-89d7-01c4528d7518@redhat.com> From: "H.J. Lu" Date: Thu, 11 May 2017 17:09:00 -0000 Message-ID: Subject: Re: [PATCH] x86: Generate PLT relocations for -z now To: "Carlos O'Donell" Cc: Szabolcs Nagy , Binutils , GNU C Library , nd Content-Type: text/plain; charset=UTF-8 X-SW-Source: 2017-05/txt/msg00343.txt.bz2 On Thu, May 11, 2017 at 9:44 AM, Carlos O'Donell wrote: > On 05/11/2017 10:51 AM, H.J. Lu wrote: >> The run-time R_X86_64_GLOB_DAT relocation against foo is >> required. There is no need to add another run-time >> R_X86_64_JUMP_SLOT relocation. We can add a linker option >> to generate the extra R_X86_64_JUMP_SLOT. But I don't think >> it should be the default. > > I don't disagree with your analysis, I disagree with the execution > of the plan. > > The plan should be: > > (a) Analyze uses of the PLT entries. > > In this case LD_AUDIT, LD_PROFILE, and ltrace all require them to > operate correctly. As I stated before, glibc and GCC have been doing everything we can to avoid PLT. > (b) Develop plan for migrating developer tooling, like LD_AUDIT, > which is a part of glibc and is well supported. > > (c) Choose one of: > > (C.1) Make PLT elision optional e.g. -z noplt > > or > > (C.2) Make LD_AUDIT work with optimizations. This is the only option. > Right now we have ignored dependent tooling that requires this > feature and have pressed on ahead with optimizations that remove > a required feature. > > If we don't want to do (C.1), then how do we do (C.2)? > > -- > Cheers, > Carlos. -- H.J.