From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) by sourceware.org (Postfix) with ESMTPS id 826F8385803F for ; Thu, 15 Apr 2021 20:44:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 826F8385803F Received: by mail-qt1-x834.google.com with SMTP id z15so11193026qtj.7 for ; Thu, 15 Apr 2021 13:44:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=z3Apk6jiuuxuS1QyDp898AfKqL2a53uSdHJ8jIv/bcE=; b=LX1VMCZREJ9fBDBG1X2Whr8FrSk/GoNaYgsjOd7ABi7QpqsRD6L8RTGfDxYVvyG1oq mrLykGk3MFttxDVSyt8Gc9VSyj9DxhBK31H6/GrXIiOxtwlzHGhGos47ZnePFrlzpnpc cjznjwk6MFJftj6GPb70AChgKkA5oMQjKzGXlNNwuLfVPNkwOz6g/2Hizea/slcfePJ0 zgiLxWPMQZhsBHqOTVWMtj/rg0yNS0D1H2YR50eFJLxk/oKZk3G54+UYxNWK4Gt77yxi EW80iVDz97Wl7zwYzsXy3khXc1J0a4AXUUBClEMwNM60SgjLdJbaEPYTXfuaGT3HyGav NrzQ== X-Gm-Message-State: AOAM533EGjD5vesSOUQLe5M83Uyy2V0GElfFVfP7Qib3NOdBj4zDEvT0 snIIC2I1QG9+ekrWnJFzOGEOK77dDI4u/uxE X-Google-Smtp-Source: ABdhPJxnSp/RNmNBPwRu2zig+YypSlsFS9Dj48YYyNisomV7HqomxgK6cb8PezDzheHxVfg9Nv0QRw== X-Received: by 2002:ac8:110f:: with SMTP id c15mr4847423qtj.251.1618519460956; Thu, 15 Apr 2021 13:44:20 -0700 (PDT) Received: from [192.168.1.132] ([177.194.41.149]) by smtp.gmail.com with ESMTPSA id l12sm2637058qkk.59.2021.04.15.13.44.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Apr 2021 13:44:20 -0700 (PDT) Subject: Re: [PATCH] powerpc: Remove backtrace implementation To: Tulio Magno Quites Machado Filho , Paul E Murphy , Florian Weimer , Adhemerval Zanella via Libc-alpha References: <20210212170941.1786380-1-adhemerval.zanella@linaro.org> <878s7ti4m0.fsf@oldenburg.str.redhat.com> <90d1d0e5-a31e-fbac-ead0-7f76f2645cd9@linaro.org> <87sg5n3g04.fsf@linux.ibm.com> <87blcbx91u.fsf@oldenburg.str.redhat.com> <20210226173909.nikuk5bohko2clqj@work-tp> <57f96ee4-7586-de09-2234-ad09c347be84@linux.ibm.com> <87y2djzk1a.fsf@linux.ibm.com> From: Adhemerval Zanella Message-ID: <12ac2270-c3af-a364-ad12-367220991d06@linaro.org> Date: Thu, 15 Apr 2021 17:44:18 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <87y2djzk1a.fsf@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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: Thu, 15 Apr 2021 20:44:26 -0000 On 15/04/2021 11:42, Tulio Magno Quites Machado Filho wrote: > Paul E Murphy via Libc-alpha writes: > >> Ping? This seems like a beneficial change. Using the unwind >> information makes for a much more robust backtrace with other languages >> which support C bindings but do not use the same ABI (specifically >> calling to and from go code in C). >> >> Should we instead turn the existing ppc backtrace into a compat symbol? >> This seems like it would address Tulio's issue with older binaries. > > If we do this, we'll never be able to remove the old implementation, which was > Adhemerval's goal. > I particularly agree that duplicated code should be removed and I believe it > would be helpful if libgcc had the fallback code. > As before, I don't think this is a ABI breaker and making powerpc align with other architecture simplifies the code and align the expectation. And afaik all projects that do require fast unwinder do it themselves (libsanitizer for instance) instead.