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 8121538582B8 for ; Tue, 18 Oct 2022 11:15:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8121538582B8 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=1666091744; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=xeNBzr0o+BLpBa+Ojx3zm3xg3j7i64mrdP7dsntMsSw=; b=QQ5hshlY9y7G3VuvPpGx0z65dTyF5K6PLPb9D9DrQfUzhiP7LOQUAJb/MUgWYU90Q0hgzo HFzaSDJULP97s4qk7qrcJmYXnw5MaXEOYFzFGIrZ2Cp6Utj81aOUTHHgx4SOibqrpKLh2G BkJmTsulFEgsiBuPb/EAB6Mq/t0nDZ8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-640-7GP_Si7iNzCE37BGMuIzrQ-1; Tue, 18 Oct 2022 07:15:37 -0400 X-MC-Unique: 7GP_Si7iNzCE37BGMuIzrQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7D8A929AA38A for ; Tue, 18 Oct 2022 11:15:37 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.193.252]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3E15511457CA; Tue, 18 Oct 2022 11:15:37 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 29IBFY6S057039 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 18 Oct 2022 13:15:35 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 29IBFYKX057038; Tue, 18 Oct 2022 13:15:34 +0200 Date: Tue, 18 Oct 2022 13:15:33 +0200 From: Jakub Jelinek To: Ulrich Drepper Cc: Jason Merrill , gcc-patches@gcc.gnu.org Subject: Re: [PATCH] C++ API database Message-ID: Reply-To: Jakub Jelinek References: <2afc8d88-2c00-a134-7d5d-da6b7c388563@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Tue, Oct 18, 2022 at 01:01:14PM +0200, Ulrich Drepper via Gcc-patches wrote: > This is of course not a new problem in general. GNU make has for a long > time support for order-only prerequisites. With those one can exactly > express what is needed: > > ifeq ($(ENABLE_MAINTAINER_RULES), true) > FOO.h: FOO.gperf > else > FOO.h: | FOO.gperf > endif > gperf ... > > ifeq ($(ENABLE_MAINTAINER_RULES), true) > FOO.gperf: CSV > else > FOO.gperf: | CSV > endif > python ... > > The question here is whether there is a reason not to depend on GNU make > features (and whatever other make implemented this extension). GCC requires GNU make and we already use order-only prerequisities in gcc/Makefile.in : # In order for parallel make to really start compiling the expensive # objects from $(OBJS) as early as possible, build all their # prerequisites strictly before all objects. $(ALL_HOST_OBJS) : | $(generated_files) Jakub