Date: Wed, 21 Dec 2016 14:06:44 +0000 (UTC) From: Ed Maste <emaste@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r310365 - head/contrib/llvm/projects/libunwind/src Message-ID: <201612211406.uBLE6isw082252@repo.freebsd.org>
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Author: emaste Date: Wed Dec 21 14:06:44 2016 New Revision: 310365 URL: https://svnweb.freebsd.org/changeset/base/310365 Log: libunwind: make __{de,}register_frame compatible with libgcc API The libgcc __register_frame and __deregister_frame functions take a pointer to a set of FDE/CIEs, terminated by an entry where length is 0. In Apple's libunwind implementation the pointer is taken to be to a single FDE. I suspect this was just an Apple bug, compensated by Apple- specific code in LLVM. See lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp and http://lists.llvm.org/pipermail/llvm-dev/2013-April/061737.html for more detail. This change is based on the LLVM RTDyldMemoryManager.cpp. It should later be changed to be alignment-safe. Reported by: dim Reviewed by: dim MFC after: 1 month Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D8869 Modified: head/contrib/llvm/projects/libunwind/src/UnwindLevel1-gcc-ext.c Modified: head/contrib/llvm/projects/libunwind/src/UnwindLevel1-gcc-ext.c ============================================================================== --- head/contrib/llvm/projects/libunwind/src/UnwindLevel1-gcc-ext.c Wed Dec 21 11:34:16 2016 (r310364) +++ head/contrib/llvm/projects/libunwind/src/UnwindLevel1-gcc-ext.c Wed Dec 21 14:06:44 2016 (r310365) @@ -224,6 +224,47 @@ _LIBUNWIND_EXPORT uintptr_t _Unwind_GetI #if _LIBUNWIND_SUPPORT_DWARF_UNWIND +#ifdef __FreeBSD__ + +// Based on LLVM's lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp +// and XXX should be fixed to be alignment-safe. +static void processFDE(const char *addr, bool isDeregister) { + uint64_t length; + while ((length = *((const uint32_t *)addr)) != 0) { + const char *p = addr + 4; + if (length == 0xffffffff) { + length = *((const uint64_t *)p); + p += 8; + } + uint32_t offset = *((const uint32_t *)p); + if (offset != 0) { + if (isDeregister) + _unw_remove_dynamic_fde((unw_word_t)(uintptr_t)addr); + else + _unw_add_dynamic_fde((unw_word_t)(uintptr_t)addr); + } + addr = p + length; + } +} + +/// Called by programs with dynamic code generators that want to register +/// dynamically generated FDEs, with a libgcc-compatible API. + +_LIBUNWIND_EXPORT void __register_frame(const void *addr) { + _LIBUNWIND_TRACE_API("__register_frame(%p)", addr); + processFDE(addr, false); +} + +/// Called by programs with dynamic code generators that want to unregister +/// dynamically generated FDEs, with a libgcc-compatible API. +_LIBUNWIND_EXPORT void __deregister_frame(const void *addr) { + _LIBUNWIND_TRACE_API("__deregister_frame(%p)", addr); + processFDE(addr, true); +} + + +#else + /// Called by programs with dynamic code generators that want /// to register a dynamically generated FDE. /// This function has existed on Mac OS X since 10.4, but @@ -243,6 +284,7 @@ _LIBUNWIND_EXPORT void __deregister_fram _unw_remove_dynamic_fde((unw_word_t)(uintptr_t) fde); } +#endif // The following register/deregister functions are gcc extensions. // They have existed on Mac OS X, but have never worked because Mac OS X
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