From owner-freebsd-ppc@freebsd.org Mon Oct 12 03:05:48 2015 Return-Path: Delivered-To: freebsd-ppc@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 1F488A119F1 for ; Mon, 12 Oct 2015 03:05:48 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-1.reflexion.net [208.70.210.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id C4CFC13DC for ; Mon, 12 Oct 2015 03:05:47 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 31163 invoked from network); 12 Oct 2015 03:05:46 -0000 Received: from unknown (HELO mail-cs-01.app.dca.reflexion.local) (10.81.19.1) by 0 (rfx-qmail) with SMTP; 12 Oct 2015 03:05:46 -0000 Received: by mail-cs-01.app.dca.reflexion.local (Reflexion email security v7.70.2) with SMTP; Sun, 11 Oct 2015 23:05:46 -0400 (EDT) Received: (qmail 2850 invoked from network); 12 Oct 2015 03:05:46 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 12 Oct 2015 03:05:46 -0000 X-No-Relay: not in my network X-No-Relay: not in my network Received: from [192.168.1.108] (c-67-170-167-181.hsd1.or.comcast.net [67.170.167.181]) by iron2.pdx.net (Postfix) with ESMTPSA id 8F71B1C43A3; Sun, 11 Oct 2015 20:05:39 -0700 (PDT) From: Mark Millard Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Subject: STABLE clang planned update MFC path (3.4.1 STABLE, 3.7.0, CURRENT) vs. powerpc64 Date: Sun, 11 Oct 2015 20:05:44 -0700 Message-Id: <7ABB859E-8321-48F7-885C-6667243C1388@dsl-only.net> Cc: FreeBSD PowerPC ML To: freebsd-stable@freebsd.org Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) X-Mailer: Apple Mail (2.2104) X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Oct 2015 03:05:48 -0000 On 2014-Oct-11 Dimitry Andric wrote: > On 11 Oct 2015, at 14:05, Piotr Kubaj > wrote: > > > > AFAIK if there had been such plans, they were dropped long ago. The > > reasoning it can't be done (at least for now) is that versions = 3.5.0+ > > require C++11-capable stack and that would break upgrades from = 9-STABLE > > (if the user still uses GCC, as is by default). So, LLVM in = stable/10 > > will probably be upgraded when stable/9 goes EOL. >=20 >=20 > If stable/10 had clang 3.5 or higher, you could still upgrade from > stable/9. It would only require you to do the upgrade in two steps: >=20 > * Rebuild and reinstall your stable/9 world using WITH_CLANG, > WITH_CLANG_IS_CC, and WITH_LIBCPLUSPLUS. This will install clang > 3.4.1 and libc++, and make clang the default compiler. > * Checkout stable/10 (or even head), and build/install it in the = regular > fashion. >=20 > I am personally not against merging newer llvm/clang versions into > stable/10. But the "silent agreement" has always been that you could > upgrade easily from the latest stable/X to stable/X+1, and the above > two-step process breaks that, or at least makes it more complicated. >=20 > Last but not least, note that this would only apply to the = architectures > that *can* actually build clang 3.4.1 and libc++ on stable/9. This is > currently limited to x86, little-endian arm and powerpc (64 bit, I'm > unsure about 32 bit). >=20 > -Dimitry lib/csu/powerpc64/Makefile in head has updates and comments (2015-Feb-05 = or so) about "powerpc64 csu needs to be built by gcc, so enforce that". = It is tied to clang not supporting -mlongcall and "testing shows a clang = linked with a [#] clang-built csu segfaults". The forcing of gcc use in = head looks like: CC:=3D gcc COMPILER_TYPE:=3D gcc which is not in stable/10's variant. stable/10 has a lib/csu/powerpc64/Makefile that does not force gcc but = still has: CFLAGS+=3D -I${.CURDIR}/../common \ -I${.CURDIR}/../../libc/include \ -mlongcall and so has -mlongcall in use on the command lines. Unless -mlongcall = support used to be in place for clang and was later removed, a = rebuilding of FreeBSD 9 or 10 that includes a lib/csu/powerpc64/ rebuild = likely fails to build under WITH_CLANG_IS_CC. I'm not sure about going all the way back to FreeBSD 9 but this suggests = that clang was for some time --and recently has been-- insufficient on = its own for reliable(?) powerpc64 builds (2015-Feb-05). It may be best = to consider powerpc64 omitted from the "clang 3.4.1 and libc++" list in = that last paragraph given the "upgrade easily" context intended. (If there is an easy powerpc64 upgrade then I'd like to see notes about = it: Other contexts might be able to use similar techniques. I started my = explorations with 10.) =3D=3D=3D Mark Millard markmi at dsl-only.net