Author: Adrian Vogelsgesang Date: 2022-09-16T06:29:49-07:00 New Revision: c9cffdde393f646acf62d6160e7fa6613e038508
URL: https://github.com/llvm/llvm-project/commit/c9cffdde393f646acf62d6160e7fa6613e038508 DIFF: https://github.com/llvm/llvm-project/commit/c9cffdde393f646acf62d6160e7fa6613e038508.diff LOG: [libunwind] Fix usage of `_dl_find_object` on 32-bit x86 On 32-bit x86, `_dl_find_object` also returns a `dlfo_eh_dbase` address. So far, compiling against a version of `_dl_find_object` which returns a `dlfo_eh_dbase` was blocked using a `#if` + `#error`. This commit now removes this compile time assertion and simply ignores the returned `dlfo_eh_dbase`. All test cases are passing on a 32-bit build now. According to https://www.gnu.org/software/libc/manual/html_node/Dynamic-Linker-Introspection.html, `dlfo_eh_dbase` should be the base address for all DW_EH_PE_datarel relocations. However, glibc/elf/dl-find_object.h says that eh_dbase is the relocated DT_PLTGOT value. I don't understand how those two statements fit together, but to fix 32-bit x86, ignoring `dlfo_eh_dbase` seems to be good enough. Fixes #57733 Differential Revision: https://reviews.llvm.org/D133846 Added: Modified: libunwind/src/AddressSpace.hpp Removed: ################################################################################ diff --git a/libunwind/src/AddressSpace.hpp b/libunwind/src/AddressSpace.hpp index 315289cd4211b..b0135b0c0519c 100644 --- a/libunwind/src/AddressSpace.hpp +++ b/libunwind/src/AddressSpace.hpp @@ -584,11 +584,6 @@ inline bool LocalAddressSpace::findUnwindSections(pint_t targetAddr, // support for _dl_find_object on other unwind formats is not implemented, // yet. #if defined(DLFO_STRUCT_HAS_EH_DBASE) & defined(_LIBUNWIND_SUPPORT_DWARF_INDEX) - // We expect to run on a platform which does not use a base address for - // exception information. -#if DLFO_STRUCT_HAS_EH_DBASE -#error dlfo_eh_dbase is not supported for DWARF-based unwinding -#endif // We expect `_dl_find_object` to return PT_GNU_EH_FRAME. #if DLFO_EH_SEGMENT_TYPE != PT_GNU_EH_FRAME #error _dl_find_object retrieves an unexpected section type _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
