From owner-freebsd-hackers@freebsd.org Wed Sep 14 19:47:14 2016 Return-Path: Delivered-To: freebsd-hackers@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 3E56ABDAB23 for ; Wed, 14 Sep 2016 19:47:14 +0000 (UTC) (envelope-from pfg@FreeBSD.org) Received: from nm19-vm0.bullet.mail.bf1.yahoo.com (nm19-vm0.bullet.mail.bf1.yahoo.com [98.139.213.162]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E9D3D1F22 for ; Wed, 14 Sep 2016 19:47:13 +0000 (UTC) (envelope-from pfg@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1473882258; bh=bAAx7L86y6LWX32JNInEcbtayS6FFG8CrB7yCQHzQDM=; h=Subject:To:References:Cc:From:Date:In-Reply-To:From:Subject; b=JTi/a1pIQtLB6aXAVHGWdETuodcYt27hOdhvUPYXzsKKSAV4iNL9WR0JKzj9MVUQFT8exhkIj3sxfuG7WLjMv+PmAoMu1u2uzUP8VCreYyF9KP1wilWOjIE0CAs2zHlZWK/a75cbcLDmKsUsNHhiKeiqBwGtXxlX1MMq7aQunI+jxknz+euNlxSRS2MMOqy3v7sqeAGw27VYfrp+q+zWlqm4pP3aY6MeEZ0Yk/5B+lQ8trBxWgFmq0HFxe/OMEvciIUjLMS3I+oq+dESzcbTb+LJ7/e/PmusGleimb/nI8qOYnPaxi22aMOSbXm8AJy2PlvrNtyQ29Or/UoXt26jkw== Received: from [98.139.215.140] by nm19.bullet.mail.bf1.yahoo.com with NNFMP; 14 Sep 2016 19:44:18 -0000 Received: from [68.142.230.73] by tm11.bullet.mail.bf1.yahoo.com with NNFMP; 14 Sep 2016 19:44:18 -0000 Received: from [127.0.0.1] by smtp230.mail.bf1.yahoo.com with NNFMP; 14 Sep 2016 19:44:18 -0000 X-Yahoo-Newman-Id: 384503.57015.bm@smtp230.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: L6OWQMUVM1nxW368upeZykzlsXkAQT6awlhAsbnVdJq1AZa Bz5h3O11x0trl.Go6IJTZSGq1l923MCE8Kbbvv6XmQjLcIuGylVhLKxK.qvn oBw32B_jZPj7hW8jIsmeJVbxb14n15G8EUAw9xm8ZEAAHndbEueBhyQgrTM3 Ds5SnZvtT07GTsa39YbgHAjlfUvjL4HRXokwgPZZUXI6GoTDHOtogeVtK5Jx 9KQtXdZY0zCsDmwIcmCDF8N0wJZnVa_3.SLdmxJ22JLPfUDNQHz1yazBLwJ2 0kyUzOUTcwSQzG_Giw6cO3.sgFgmO4AUA5Wkbjy_25q0Zu7HU1mDq8qeeWN1 IbH8JBu_tTvnxd3JdbKiKDW3W5rEKvicr9S1H2.uRI5aSyf8_jaD7b5CJTMG nSz3KqiXKBvTdm2xtd.m9loS0g2lcJipcCB7UyJhA4kdy_eIRIPDOq8Xlt75 MRXCJ216YY_G26qO9QntrrPNJWqgMTS.5Hqp1yym74zttQ9a9xmy9GAjdoaP FVW3gfcfWSdjwM6_1ynaI9ZeEH8D5fKD2coeVbDM4ZqMPGg-- X-Yahoo-SMTP: xcjD0guswBAZaPPIbxpWwLcp9Unf Subject: Re: Is replacing alloca(3) where possible a good thing to do? To: Cedric Blancher References: <90f37d14-a187-06b2-6187-7a9c1890a73f@FreeBSD.org> Cc: FreeBSD Hackers From: Pedro Giffuni Message-ID: <5cb743dd-60fd-8018-eaf7-fe10b8db211c@FreeBSD.org> Date: Wed, 14 Sep 2016 14:44:25 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Sep 2016 19:47:14 -0000 Hello; On 14/09/2016 14:14, Cedric Blancher wrote: > dtrace can do VLA > > Are there other arguments? It was a while ago and I don't remember other than the fact that alloca() exists on all platforms and just works fine so why bother. This was only a discussion in the context of printf(1) and as I wrote we parted different ways there. If there are other notable cases then please upstream those changes first. Pedro. > Ced > > On 14 September 2016 at 21:11, Pedro Giffuni wrote: >> >> On 14/09/2016 13:54, Cedric Blancher wrote: >>> Who was the "principal Illumos developer"? I remember some heated >>> discussions, mostly rooted in 'we stick with ANSI C' and because the >>> CTF/dwarf tools in Illumos were unable to handle VLA and no one was >>> interested in fixing the BUGS in their toolchain, so the cheapest >>> solution was done: VLA was declared persona non grata. Saves company >>> money. >> >> Yes, the non-accessibility of VLAs for Dtrace was the main argument. This >> was a private conversation with Garrett D'Amore who did some nice >> enhancements to our printf(1). >> >>> Typical Sun policy which was one of the reasons which sealed the >>> downfall of Sun Microsystems. >>> >>> But this is NO ARGUMENT for FreeBSD... >> >> Our printf(1) implementation has all their enhancements but uses a VLA >> instead of alloca. >> >> This said, whatever illumos wants to keep in their code is relevant as we >> want to make it easy to merge ZFS and Dtrace changes back and forth. >> >> Pedro. > >