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 4FADD3858431 for ; Thu, 17 Feb 2022 12:08:49 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 4FADD3858431 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=1645099729; 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=G0yp/Ho734agrNUAm04Ea+kDHKmkjjMjPrR6j3gKYfg=; b=Vl8ec5JFrDN27XO+QxeAP2daN02mLdjPt+84BADvU4/+xuUip3aDwmS4a42L8m9ZcVFzWi LeBamIh9XDl5PN3Cep+YUt1vFlXjenA/rQAN2cG77p5aXoqfuYuqmbv1EIUZKzEimRCd/o 8BvsF63L+nEE1Li8ZV/DgnHMN9PGhpY= 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-450-ElVxJ-TeOv2Q9ci8L6LL7Q-1; Thu, 17 Feb 2022 07:08:47 -0500 X-MC-Unique: ElVxJ-TeOv2Q9ci8L6LL7Q-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27449100C609 for ; Thu, 17 Feb 2022 12:08:47 +0000 (UTC) Received: from calimero.vinschen.de (unknown [10.36.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EBCEC73153 for ; Thu, 17 Feb 2022 12:08:46 +0000 (UTC) Received: by calimero.vinschen.de (Postfix, from userid 500) id 83FD2A80896; Thu, 17 Feb 2022 13:08:45 +0100 (CET) Date: Thu, 17 Feb 2022 13:08:45 +0100 From: Corinna Vinschen To: newlib@sourceware.org Subject: Re: [PATCH v2] newlib: libm: merge build up a directory Message-ID: Reply-To: newlib@sourceware.org Mail-Followup-To: newlib@sourceware.org References: <20220212203450.19650-1-vapier@gentoo.org> <20220217044256.5483-1-vapier@gentoo.org> MIME-Version: 1.0 In-Reply-To: <20220217044256.5483-1-vapier@gentoo.org> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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, 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: Thu, 17 Feb 2022 12:08:50 -0000 On Feb 16 23:42, Mike Frysinger wrote: > Convert all the libm/ subdir makes into the top-level Makefile. This > allows us to build all of libm from the top Makefile without using any > recursive make calls. This is faster and avoids the funky lib.a logic > where we unpack subdir archives to repack into a single libm.a. The > machine override logic is maintained though by way of Makefile include > ordering, and source file accumulation in libm_a_SOURCES. > > One thing to note is that this will require GNU Make because of: > libm_a_CFLAGS = ... $(libm_a_CFLAGS_$(subst /,_,$(@D))) > This was the only way I could find to supporting per-dir compiler > settings, and I couldn't find a POSIX compatible way of transforming > the variable content. I don't think this is a big deal as other > Makefiles in the tree are using GNU Make-specific syntax, but I call > this out as it's the only one so far in the new automake code that > I've been writing. > > Automake doesn't provide precise control over the output object names > (by design). This is fine by default as we get consistent names in all > the subdirs: libm_a-.o. But this relies on using the same set > of compiler flags for all objects. We currently compile libm/common/ > with different optimizations than the rest. > > If we want to compile objects differently, we can create an intermediate > archive with the subset of objects with unique flags, and then add those > objects to the main archive. But Automake will use a different prefix > for the objects, and thus we can't rely on ordering to override. > > But if we leverage $@, we can turn Automake's CFLAGS into a multiplex > on a per-dir (and even per-file if we wanted) basis. Unfortunately, > since $@ contains /, Automake complains it's an invalid name. While > GNU Make supports this, it's a POSIX extension, so Automake flags it. > Using $(subst) avoids the Automake warning to get a POSIX compliant > name, albeit with a GNU Make extension. > --- > v2 > - rebased onto latest tree > - fixed a parallel build issue with generated newlib headers & libm objects Ok, do your thing. Thx, Corinna