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 B5F503857B92 for ; Sat, 18 Jun 2022 03:54:30 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B5F503857B92 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-358-RQmgsY_fPDWmAYs3ox-QNA-1; Fri, 17 Jun 2022 23:54:26 -0400 X-MC-Unique: RQmgsY_fPDWmAYs3ox-QNA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 86D083C0CD3E; Sat, 18 Jun 2022 03:54:26 +0000 (UTC) Received: from greed.delorie.com (unknown [10.22.8.54]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 71F2AC28115; Sat, 18 Jun 2022 03:54:26 +0000 (UTC) Received: from greed.delorie.com.redhat.com (localhost [127.0.0.1]) by greed.delorie.com (8.15.2/8.15.2) with ESMTP id 25I3sPkX4125406; Fri, 17 Jun 2022 23:54:25 -0400 From: DJ Delorie To: Wilco Dijkstra Cc: libc-alpha@sourceware.org Subject: Re: [patch/idea] Add register scrambling to testsuite In-Reply-To: Date: Fri, 17 Jun 2022 23:54:25 -0400 Message-ID: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-5.8 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=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) 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: Sat, 18 Jun 2022 03:54:33 -0000 Wilco Dijkstra writes: > If the purpose is to debug assembler implementations, this won't work > since the compiler will use many of these registers, Er, yay? If the compiler uses the register, it will likely be non-zero, and either way, it will be more like a "real" application where ALL the registers have been used at some point. The problem happens if the registers are unused from program start to the function, and remain with the EABI initial 'zero' value. That is common in our trivial test cases. > Also this is the first time I've heard about an uninitialized read Each bug is an opportunity for something to happen the first time. > Why should we do something about uninitialized variables when the > testsuite could be improved to better test all these corner cases? Well, I'm willing to add this part. It's something that makes the testsuite overall better, is fairly simple, and within my scope. Fixing all the string tests to be more robust is a worthy goal but not something I can do. So the question becomes, why should I do something simple, when I could do nothing at all? That's a silly question; it's better to do something.