From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 4034071 for ; Tue, 26 Jul 2016 11:22:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 25B9DFD for ; Tue, 26 Jul 2016 11:22:23 +0000 (UTC) Message-ID: <1469532139.120686.274.camel@infradead.org> From: David Woodhouse To: Jiri Kosina Date: Tue, 26 Jul 2016 12:22:19 +0100 In-Reply-To: References: <87inw1skws.fsf@x220.int.ebiederm.org> <1469094899.120686.101.camel@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-piV+WrbypD4fgentEuk0" Mime-Version: 1.0 Cc: ksummit-discuss@lists.linuxfoundation.org Subject: Re: [Ksummit-discuss] [CORE TOPIC] [TECH TOPIC] Support (or move towards to) LLVM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-piV+WrbypD4fgentEuk0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2016-07-21 at 20:38 +0200, Jiri Kosina wrote: > On Thu, 21 Jul 2016, David Woodhouse wrote: >=20 > > Apart from resolutely not wanting to implement variable length arrays o= n=20 > > the stack, the LLVM folks actually seem quite keen to make things work.= =20 > > I'm interested in the problem you report above.. and note the absence o= f=20 > > a bug number. Can you provide it? >=20 > I am currently on vacation and on super-lousy internet connection, so=20 > looking through my archives is a bit complicated ... I *think* it started= =20 > in "[PATCH] usbhid: Fix lockdep unannotated irqs-off warning" thread on= =20 > lkml. >=20 > In case you're not able to find it from there, I'll do my homework=20 > mid-next week when I am back properly online. OK, thanks. So it looks like that's acknowledged to have been a bug, there's a patch to fix it at=C2=A0https://reviews.llvm.org/D6629=C2=A0which= may even have been committed already. The main sticking point for LLVM seems to be the variable length arrays on the stack (VLAIS), which is a GCC'ism that the LLVM/clang folks *really* don't want to support, and the fact that __builtin_constant_p() is basically always false under LLVM because it doesn't look very hard. --=20 David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation --=-piV+WrbypD4fgentEuk0 Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEeAw ggXiMIIDyqADAgECAhBrp4p9CteI1lEK+Vnk57ThMA0GCSqGSIb3DQEBCwUAMH0xCzAJBgNVBAYT AklMMRYwFAYDVQQKEw1TdGFydENvbSBMdGQuMSswKQYDVQQLEyJTZWN1cmUgRGlnaXRhbCBDZXJ0 aWZpY2F0ZSBTaWduaW5nMSkwJwYDVQQDEyBTdGFydENvbSBDZXJ0aWZpY2F0aW9uIEF1dGhvcml0 eTAeFw0xNTEyMTYwMTAwMDVaFw0zMDEyMTYwMTAwMDVaMHUxCzAJBgNVBAYTAklMMRYwFAYDVQQK 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