From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 35658 invoked by alias); 27 Jul 2017 07:19:39 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 35596 invoked by uid 89); 27 Jul 2017 07:19:38 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mx1.suse.de Received: from mx2.suse.de (HELO mx1.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 27 Jul 2017 07:19:37 +0000 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 3C5CBABBC; Thu, 27 Jul 2017 07:19:35 +0000 (UTC) Date: Thu, 27 Jul 2017 07:19:00 -0000 From: Richard Biener To: Jakub Jelinek cc: Jan Hubicka , gcc-patches@gcc.gnu.org Subject: Re: Patch ping In-Reply-To: <20170726173103.GX2123@tucnak> Message-ID: References: <20170725094050.GR2123@tucnak> <20170726134715.GW2123@tucnak> <20170726173103.GX2123@tucnak> User-Agent: Alpine 2.20 (LSU 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-SW-Source: 2017-07/txt/msg01747.txt.bz2 On Wed, 26 Jul 2017, Jakub Jelinek wrote: > On Wed, Jul 26, 2017 at 04:13:30PM +0200, Richard Biener wrote: > > > > You don't seem to use 'size' anywhere. > > > > > > size I thought about but then decided not to do anything with it. > > > There are two cases, one is where there is no ADDR_EXPR and it actually > > > a memory reference. > > > In that case in theory the size could be used, but it would need > > > to be used only for the positive offsets, so like: > > > if (off > 0) { > > > if (ptr + off + size < ptr) > > > runtime_fail; > > > } else if (ptr + off > ptr) > > > runtime_fail; > > > but when it is actually a memory reference, I suppose it will fail > > > at runtime anyway when performing such an access, so I think it is > > > unnecessary. And for the ADDR_EXPR case, the size is irrelevant, we > > > are just taking address of the start of the object. > > > > > > > You fail to allow other handled components -- for no good reason? > > > > > > I was trying to have a quick bail out. What other handled components might > > > be relevant? I guess IMAGPART_EXPR. For say BIT_FIELD_REF I don't think > > > I can > > > tree ptr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (t)), t); > > > > REALPART/IMAGPART_EXPR, yes. You can't address BIT_FIELD_REF > > apart those on byte boundary (&vector[4] is eventually folded to > > a BIT_FIELD_REF). Similar for VIEW_CONVERT_EXPR, but you are > > only building the address on the base? > > > > > > You fail to handle > > > > &MEM[ptr + CST] a canonical gimple invariant way of ptr +p CST, > > > > the early out bitpos == 0 will cause non-instrumentation here. > > > > > > Guess I could use: > > > if ((offset == NULL_TREE > > > && bitpos == 0 > > > && (TREE_CODE (inner) != MEM_REF > > > || integer_zerop (TREE_OPERAND (inner, 1)))) > > > The rest of the code will handle it. > > > > Yeah. > > > > > > > > > (I'd just round down in the case of bitpos % BITS_PER_UNIT != 0) > > > > > > But then the > > > tree ptr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (t)), t); > > > won't work again. > > > > Hmm. So instead of building the address on the original tree you > > could build the difference based on what get_inner_reference returns > > in bitpos/offset? > > I'm building both addresses and subtracting them to get the offset. > I guess the other option is to compute just the address of the base > (i.e. base_addr), and add offset (if non-NULL) plus bitpos / BITS_PER_UNIT > plus offset from the MEM_REF (if any). In that case it would probably > handle any handled_component_p and bitfields too. Yes. Can you try sth along this route? Should be a matter of adding offset and bitpos / BITS_PER_UNIT (thus rounded down) plus any MEM_REF offset on the base. Thanks, Richard.