Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753224AbbGBGRG (ORCPT ); Thu, 2 Jul 2015 02:17:06 -0400 Received: from terminus.zytor.com ([198.137.202.10]:44293 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753127AbbGBGRB (ORCPT ); Thu, 2 Jul 2015 02:17:01 -0400 Message-ID: <5594D748.2020304@zytor.com> Date: Wed, 01 Jul 2015 23:16:40 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Jakub Jelinek , Vladimir Makarov CC: Andy Lutomirski , gcc@gcc.gnu.org, "linux-kernel@vger.kernel.org" , Linus Torvalds , Ingo Molnar , Thomas Gleixner Subject: Re: gcc feature request / RFC: extra clobbered regs References: <20150630213736.GQ10247@tucnak.redhat.com> <559405E5.7000405@redhat.com> <20150701153133.GY10247@tucnak.redhat.com> <559424D4.6010908@redhat.com> <20150701174333.GA10247@tucnak.redhat.com> In-Reply-To: <20150701174333.GA10247@tucnak.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1271 Lines: 28 On 07/01/2015 10:43 AM, Jakub Jelinek wrote: > On Wed, Jul 01, 2015 at 01:35:16PM -0400, Vladimir Makarov wrote: >> Actually it raise a question for me. If we describe that a function >> clobbers more than calling convention and then use it as a value (assigning >> a variable or passing as an argument) and loosing a track of it and than >> call it. How can RA know what the call clobbers actually. So for the >> function with the attributes we should prohibit use it as a value or make >> the attributes as a part of the function type, or at least say it is unsafe. >> So now I see this as a *bigger problem* with this extension. Although I >> guess it already exists as we have description of different ABI as an >> extension. > > Unfortunately target attribute is function decl attribute rather than > function type. And having more attributes affect switchable targets will be > non-fun. > How on Earth does that work with existing switchable ABIs? Keep in mind that we already support multiple ABIs... -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/