From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 00/22] add support for Clang LTO Date: Fri, 3 Jul 2020 15:25:23 +0200 Message-ID: <20200703132523.GM117543@hirez.programming.kicks-ass.net> References: <20200630201243.GD4817@hirez.programming.kicks-ass.net> <20200630203016.GI9247@paulmck-ThinkPad-P72> <20200701114027.GO4800@hirez.programming.kicks-ass.net> <20200701140654.GL9247@paulmck-ThinkPad-P72> <20200701150512.GH4817@hirez.programming.kicks-ass.net> <20200701160338.GN9247@paulmck-ThinkPad-P72> <20200702082040.GB4781@hirez.programming.kicks-ass.net> <20200702175948.GV9247@paulmck-ThinkPad-P72> <20200703131330.GX4800@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200703131330.GX4800@hirez.programming.kicks-ass.net> Sender: linux-kbuild-owner@vger.kernel.org To: "Paul E. McKenney" Cc: Marco Elver , Nick Desaulniers , Sami Tolvanen , Masahiro Yamada , Will Deacon , Greg Kroah-Hartman , Kees Cook , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , Linux Kbuild mailing list , LKML , linux-pci@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" List-Id: linux-arch.vger.kernel.org On Fri, Jul 03, 2020 at 03:13:30PM +0200, Peter Zijlstra wrote: > > The prototype for GCC is here: https://github.com/AKG001/gcc/ > > Thanks! Those test cases are somewhat over qualified though: > > static volatile _Atomic (TYPE) * _Dependent_ptr a; \ One question though; since its a qualifier, and we've recently spend a whole lot of effort to strip qualifiers in say READ_ONCE(), how does, and how do we want, this qualifier to behave. C++ has very convenient means of manipulating qualifiers, so it's not much of a problem there, but for C it is, as we've found, really quite cumbersome. Even with _Generic() we can't manipulate individual qualifiers afaict. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33270 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726022AbgGCNZe (ORCPT ); Fri, 3 Jul 2020 09:25:34 -0400 Date: Fri, 3 Jul 2020 15:25:23 +0200 From: Peter Zijlstra Subject: Re: [PATCH 00/22] add support for Clang LTO Message-ID: <20200703132523.GM117543@hirez.programming.kicks-ass.net> References: <20200630201243.GD4817@hirez.programming.kicks-ass.net> <20200630203016.GI9247@paulmck-ThinkPad-P72> <20200701114027.GO4800@hirez.programming.kicks-ass.net> <20200701140654.GL9247@paulmck-ThinkPad-P72> <20200701150512.GH4817@hirez.programming.kicks-ass.net> <20200701160338.GN9247@paulmck-ThinkPad-P72> <20200702082040.GB4781@hirez.programming.kicks-ass.net> <20200702175948.GV9247@paulmck-ThinkPad-P72> <20200703131330.GX4800@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200703131330.GX4800@hirez.programming.kicks-ass.net> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Paul E. McKenney" Cc: Marco Elver , Nick Desaulniers , Sami Tolvanen , Masahiro Yamada , Will Deacon , Greg Kroah-Hartman , Kees Cook , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , Linux Kbuild mailing list , LKML , linux-pci@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Message-ID: <20200703132523.lUMBxBBxhL02rECE2t2w0Elcgi9ZxCvCmx0BuZAgLDw@z> On Fri, Jul 03, 2020 at 03:13:30PM +0200, Peter Zijlstra wrote: > > The prototype for GCC is here: https://github.com/AKG001/gcc/ > > Thanks! Those test cases are somewhat over qualified though: > > static volatile _Atomic (TYPE) * _Dependent_ptr a; \ One question though; since its a qualifier, and we've recently spend a whole lot of effort to strip qualifiers in say READ_ONCE(), how does, and how do we want, this qualifier to behave. C++ has very convenient means of manipulating qualifiers, so it's not much of a problem there, but for C it is, as we've found, really quite cumbersome. Even with _Generic() we can't manipulate individual qualifiers afaict.