From owner-freebsd-ppc@freebsd.org Thu Sep 8 02:42:23 2016 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 71ED2BD1765 for ; Thu, 8 Sep 2016 02:42:23 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-45.reflexion.net [208.70.210.45]) (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 217BE395 for ; Thu, 8 Sep 2016 02:42:22 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 4355 invoked from network); 8 Sep 2016 02:42:06 -0000 Received: from unknown (HELO mail-cs-01.app.dca.reflexion.local) (10.81.19.1) by 0 (rfx-qmail) with SMTP; 8 Sep 2016 02:42:06 -0000 Received: by mail-cs-01.app.dca.reflexion.local (Reflexion email security v8.00.0) with SMTP; Wed, 07 Sep 2016 22:42:19 -0400 (EDT) Received: (qmail 20644 invoked from network); 8 Sep 2016 02:42:18 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 8 Sep 2016 02:42:18 -0000 Received: from [192.168.0.104] (ip70-189-131-151.lv.lv.cox.net [70.189.131.151]) by iron2.pdx.net (Postfix) with ESMTPSA id 175E4EC8FEB for ; Wed, 7 Sep 2016 19:42:14 -0700 (PDT) From: Mark Millard Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Subject: Re: From llvm: Fwd: [Bug 26519] Clang 3.8.0's "Target: powerpc-unknown-freebsd11.0" code generation is violating the SVR4 ABI (SEGV can result) [fixed in llvm -r280705] Message-Id: Date: Wed, 7 Sep 2016 19:42:13 -0700 To: FreeBSD PowerPC ML Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) X-Mailer: Apple Mail (2.3124) X-BeenThere: freebsd-ppc@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Porting FreeBSD to the PowerPC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Sep 2016 02:42:23 -0000 Krzysztof Parzyszek kristof at swissmail.org wrote on Wed Sep 7 23:03:03 = UTC 2016 > What about this? https://reviews.llvm.org/D13351 >=20 >=20 > -Krzysztof >=20 > On 9/7/2016 5:50 PM, Krzysztof Parzyszek wrote: > > What are the requirements for soft-float, i.e. what conditions = exactly > > does the generated code need to meet? Is the purpose of it to = eliminate > > the use of floating point registers? > > > > Is there a library that implements the floating point operations? If > > not, that is going to be the main obstacle. > > > > -Krzysztof https://reviews.llvm.org/D13351 is for ppc32 (TARGET_ARCH=3Dpowerpc in = FreeBSD terms), not ppc64 (TARGET_ARCH=3Dpowerpc64 in FreeBSD terms). As Justin Hibbits wrote in answer to what soft-float is used for: > Soft float is required when building the kernel to prevent the = compiler from using floating point optimizations. >=20 > - - Justin I think that "optimizations" here means (in part?) avoiding the floating = point hardware as the kernel need not save/restore the registers and the = like for its own activities. Only user-space gets that service as I = understand. I have used clang/clang++ to do a partially-working FreeBSD buildworld = for TARGET_ARCH=3Dpowerpc (ppc32) based on = https://reviews.llvm.org/D13351 material having been included in clang = 3.8.0. (I had to temporarily modify the kernel to have a so-called = "red-zone" on the stack for signal delivery, effectively stepping = outside FreeBSD's TARGET_ARCH=3Dpowerpc related ABI standard.) But TARGET_ARCH=3Dpowerpc64 just reports that clang does not have = softfloat and the build stops as things are. =3D=3D=3D Mark Millard markmi at dsl-only.net