From owner-svn-src-all@FreeBSD.ORG Sun Jan 13 20:35:09 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 249D9F98; Sun, 13 Jan 2013 20:35:09 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) by mx1.freebsd.org (Postfix) with ESMTP id D9B18A3D; Sun, 13 Jan 2013 20:35:08 +0000 (UTC) Received: from svn.freebsd.org (svn.FreeBSD.org [8.8.178.70]) by svn.freebsd.org (8.14.5/8.14.5) with ESMTP id r0DKZ8he084293; Sun, 13 Jan 2013 20:35:08 GMT (envelope-from dim@svn.freebsd.org) Received: (from dim@localhost) by svn.freebsd.org (8.14.5/8.14.5/Submit) id r0DKZ8Uk084292; Sun, 13 Jan 2013 20:35:08 GMT (envelope-from dim@svn.freebsd.org) Message-Id: <201301132035.r0DKZ8Uk084292@svn.freebsd.org> From: Dimitry Andric Date: Sun, 13 Jan 2013 20:35:08 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r245384 - stable/9/contrib/gcc X-SVN-Group: stable-9 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 13 Jan 2013 20:35:09 -0000 Author: dim Date: Sun Jan 13 20:35:08 2013 New Revision: 245384 URL: http://svnweb.freebsd.org/changeset/base/245384 Log: MFC r245272: Add an ugly hack to libgcc's unwind code, to make it behave properly at runtime on amd64, when it is compiled by clang. Some versions of clang don't save and restore all callee registers, if a __builtin_eh_return() intrinsic is used in a function. This is particularly bad on amd64. Until the problem gets fixed by upstream, use an asm statement to force clang to assume the registers in question are clobbered, when invoking __builtin_eh_return(), so it will emit code to save and restore them. This should fix the crashes reported on -current with some C++ programs, particularly those that throw exceptions over multiple function boundaries. Reported by: stefanf Modified: stable/9/contrib/gcc/unwind-dw2.c Directory Properties: stable/9/contrib/gcc/ (props changed) Modified: stable/9/contrib/gcc/unwind-dw2.c ============================================================================== --- stable/9/contrib/gcc/unwind-dw2.c Sun Jan 13 19:39:13 2013 (r245383) +++ stable/9/contrib/gcc/unwind-dw2.c Sun Jan 13 20:35:08 2013 (r245384) @@ -1438,6 +1438,17 @@ uw_init_context_1 (struct _Unwind_Contex context->ra = __builtin_extract_return_addr (outer_ra); } +#if defined(__clang__) && defined(__amd64__) +/* Some versions of clang don't save and restore all callee registers, if a + __builtin_eh_return() intrinsic is used in a function. This is particularly + bad on amd64. For now, use the following ugly hack to force it to assume + those registers are clobbered, when invoking __builtin_eh_return(), so it + will emit code to save and restore them. */ +#define CLOBBER_REGS_HACK \ + __asm __volatile(" " : : : "r15", "r14", "r13", "r12", "rbx", "rdx", "rax"); +#else +#define CLOBBER_REGS_HACK +#endif /* __clang__ */ /* Install TARGET into CURRENT so that we can return to it. This is a macro because __builtin_eh_return must be invoked in the context of @@ -1448,6 +1459,7 @@ uw_init_context_1 (struct _Unwind_Contex { \ long offset = uw_install_context_1 ((CURRENT), (TARGET)); \ void *handler = __builtin_frob_return_addr ((TARGET)->ra); \ + CLOBBER_REGS_HACK \ __builtin_eh_return (offset, handler); \ } \ while (0)