From owner-svn-src-head@freebsd.org Sat Oct 10 15:14:41 2015 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5DD8CA10166; Sat, 10 Oct 2015 15:14:41 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: from mail-io0-x229.google.com (mail-io0-x229.google.com [IPv6:2607:f8b0:4001:c06::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 1A0821935; Sat, 10 Oct 2015 15:14:41 +0000 (UTC) (envelope-from carpeddiem@gmail.com) Received: by iow1 with SMTP id 1so118192921iow.1; Sat, 10 Oct 2015 08:14:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=xc1jSdpeIWl7EC8A/yZJ18KPBXqfBP9tiZwJVE0tsso=; b=D76+GPzC8AH8k4c/BLcPbknM6kwKCj17Vf+McWjbc4slauz+SIY0H0LNCTOCEogEhn mQjSZnr06fQm5lSBsUktAQc6+NAgWCu0XXZyhn98PmEdn1MRiWm9M9KEUXCmP7wGSGbC aDmmx3LvmabGw3dzOeFI5FE28pl3e4aFRJaHvyNNPof5vI9AeKVTDW/K735T5p0X4vYK N4KPdnD6Ofz4GI8OWEjnJHfi8oANpmOfqxTPHzC1WXgwZefAb9bt1p510rDEyeX3zMrG iU3kCkbpiicMR04/P8NKlqCm8nFQ+D3IMTQkpZhKUXYCrbhdwv6W9SHm7y6/2FMEKE86 VdKw== MIME-Version: 1.0 X-Received: by 10.107.130.149 with SMTP id m21mr20474585ioi.180.1444490080482; Sat, 10 Oct 2015 08:14:40 -0700 (PDT) Sender: carpeddiem@gmail.com Received: by 10.107.158.75 with HTTP; Sat, 10 Oct 2015 08:14:40 -0700 (PDT) Received: by 10.107.158.75 with HTTP; Sat, 10 Oct 2015 08:14:40 -0700 (PDT) In-Reply-To: <20151010125348.GF2257@kib.kiev.ua> References: <201510091821.t99ILjHI054211@repo.freebsd.org> <20151010060846.GA2257@kib.kiev.ua> <20151010120311.GE2257@kib.kiev.ua> <20151010125348.GF2257@kib.kiev.ua> Date: Sat, 10 Oct 2015 15:14:40 +0000 X-Google-Sender-Auth: bKudNBfZTZrr8d_e0n-goEukJrA Message-ID: Subject: Re: svn commit: r289072 - in head/contrib: libc++/src llvm/lib/Transforms/Vectorize From: Ed Maste To: Konstantin Belousov Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, Dimitry Andric , "svn-src-head@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.20 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Oct 2015 15:14:41 -0000 On Oct 10, 2015 8:53 AM, "Konstantin Belousov" wrote: > > On Sat, Oct 10, 2015 at 12:24:33PM +0000, Ed Maste wrote: > > On 10 October 2015 at 12:03, Konstantin Belousov wrote: > > >> The declaration is extern ostream cout; which correctly has 8 byte alignment. > > > The alignment of the declaration does not matter, most likely. > > > I am not sure what you mean by saying that 8 byte alignment is desirable, > > > while compiler generates accesses (movdqa) which assume 16-byte alignment. > > > > I mean that this object is naturally expected to have 8-byte > > alignment. In previous versions of libc++.so shipped with FreeBSD it > > did, and can't be changed now (cout comes from the binary itself, via > > a copy relocation). > No, the natural alignment for char[] is 1, while ABI requires an array > longer than 15 bytes to have 16-bytes alignment. Right, but the proper alignment for ostream is 8; it's only because of the slightly bizarre definition as a char array that we end up with this 16 byte ABI alignment.