From owner-freebsd-toolchain@freebsd.org Tue Apr 24 20:24:03 2018 Return-Path: Delivered-To: freebsd-toolchain@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 887FBFB2350 for ; Tue, 24 Apr 2018 20:24:03 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 1E31669CCC for ; Tue, 24 Apr 2018 20:24:03 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id D170EFB234F; Tue, 24 Apr 2018 20:24:02 +0000 (UTC) Delivered-To: toolchain@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C01BDFB234E for ; Tue, 24 Apr 2018 20:24:02 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 606CC69CBD for ; Tue, 24 Apr 2018 20:24:02 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 8BCD31D875 for ; Tue, 24 Apr 2018 20:24:01 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w3OKO1Gh086112 for ; Tue, 24 Apr 2018 20:24:01 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w3OKO1sl086111 for toolchain@FreeBSD.org; Tue, 24 Apr 2018 20:24:01 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: toolchain@FreeBSD.org Subject: [Bug 227723] clang 6.0 breaks php56/opcache Date: Tue, 24 Apr 2018 20:24:01 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: 11.1-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: dim@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: ale@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-toolchain@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Maintenance of FreeBSD's integrated toolchain List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Apr 2018 20:24:03 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D227723 --- Comment #6 from Dimitry Andric --- After some bisecting, it turns out this behavior changed due to the followi= ng upstream commit: https://reviews.llvm.org/rL313784 ("Remove offset size che= ck in nullptr arithmetic handling") and https://reviews.llvm.org/rL313666 ("Te= ach clang to tolerate the 'p =3D nullptr + n' idiom used by glibc"). See also https://reviews.llvm.org/D37042. What PHP5 is doing is, strictly speaking, undefined behavior, as adding num= bers to null pointers is normally not allowed. In the upstream commit, Andrew Kaylor has apparently tried to make this work, at least partially, for a few specific cases used in glibc. PHP7 and later use a completely different way of storing these variable/num= ber hybrids, which is not affected by this, as it apparently avoids any null pointer arithmetic. I'll see if I can get some feedback from Andrew on this. --=20 You are receiving this mail because: You are on the CC list for the bug.=