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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 8F125385AC3D for ; Wed, 23 Feb 2022 08:56:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8F125385AC3D Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645606591; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=9ximHv+vr8eRyUaBBD0oNrvI9aQHGukJnLxkE4c0yS4=; b=B6wkoP4C1dEBFb+Ckm18zD0XA9MhyHTknNkwCRREDf33g1rBYEWqoyQBC0YblXBsBNG3vo viwFI2NW8aaoU45PEd7LNFnxlBboo/eDVCTvQz166VrVqywMWkzSrIpB1nO22War8k92Gy jX1cQG6l+O8vW9SvMmPlgAp7/5STtMI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-274-FLDBa1BQMXCpZCYCBJ_VWg-1; Wed, 23 Feb 2022 03:56:28 -0500 X-MC-Unique: FLDBa1BQMXCpZCYCBJ_VWg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6AE00801AB2 for ; Wed, 23 Feb 2022 08:56:27 +0000 (UTC) Received: from calimero.vinschen.de (unknown [10.36.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3AEA57219B for ; Wed, 23 Feb 2022 08:56:27 +0000 (UTC) Received: by calimero.vinschen.de (Postfix, from userid 500) id A8005A80D52; Wed, 23 Feb 2022 09:56:25 +0100 (CET) Date: Wed, 23 Feb 2022 09:56:25 +0100 From: Corinna Vinschen To: newlib@sourceware.org Subject: Re: [PATCH v2] newlib: libm: workaround ar duplicate member behavior Message-ID: Reply-To: newlib@sourceware.org Mail-Followup-To: newlib@sourceware.org References: <20220221204327.2945-1-vapier@gentoo.org> <20220222002114.10214-1-vapier@gentoo.org> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vinschen@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: newlib@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Feb 2022 08:56:33 -0000 On Feb 22 12:17, Mike Frysinger wrote: > On 22 Feb 2022 12:34, Jon Turney wrote: > > On 22/02/2022 11:31, Corinna Vinschen wrote: > > > On Feb 21 19:21, Mike Frysinger wrote: > > >> GNU ar has undocumented behavior where it doesn't dedupe its inputs if > > >> they're all on the same command line, so we have to dedupe ourselves. > > >> --- > > >> v2 > > >> - use awk to dedupe the object list > > > > I think this could still at least use a comment about how the ordering > > of the inputs relates to which duplicate object are dropped and which > > are kept. > > i had updated the comment locally already and just hadn't posted it: > ## GNU ar has undocumented behavior when specifying the same name multiple times > ## in a single invocation, so we have to dedupe ourselves. The algorithm here: > ## - Generates the set of unique objects based on the basename. > ## - Favors objects later in the list (since machine objects come last). > ## - Outputs object list in same order as input for reproducibility. > > > (I'm assuming cpu-specific ones are meant to be kept in preference to > > generic routines, but how does this achieve that?) > > > > > This seems to work. > > > > > > However, what do we have to do in future to make sure the order is > > > always correct? > > i've documented this in 3 places, so think it's fine. > > (1) libc/Makefile.inc & (2) libm/Makefile.inc both have: > ## The order of includes is important for two reasons: > ## * The integrated documentation (chapter ordering). > ## * Object overridding -- machine dir must come last. > ## Do not change the order without considering the doc impact. > > (3) in the heavily rewritten build documentation i sent out [1]. > it's pending review from folks, so hasn't been merged yet. > > > > And the heritic question: Wouldn't it be safer to keep the old > > > per-subdir lib.a logic? > > i think this is a false dichotomy. the lib.a logic has the same problem, > albeit it was never documented: if the order of SUBDIRS isn't maintained, > then the machine overrides do not work correctly. if the order of the > lib.a unpacking was not done correctly, then the machine overrides do not > work correctly. the fact that it's been "stable for so long" isn't due > to the code being written well (no offense), it's because it's been so > dense & undocumented that no one has wanted to touch it with a 3m pole :P. > > > Considering the problem in the next larger context: why are we doing > > this at all? > > > > Is this just so the generic fenv routines are chewed on as they contain > > the doc markup? In which case it would be simpler to do that explicitly. > > > > If it's so that a cpu- specific fenv doesn't need to provide all the > > objects, well, that could be done explicitly as well, I think? > > assuming you're asking about the machine-override logic specifically and > not "why am i changing the build system at all", then the current newlib > design supports more than fenv. fortunately, i believe i already wrote > up all the docs you want :). please give it a look and see if i missed > anything. > [1] https://sourceware.org/pipermail/newlib/2022/019275.html > -mike Ok, thanks, please push. Corinna