https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94891
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Szabolcs Nagy <n...@gcc.gnu.org>: https://gcc.gnu.org/g:b097c7a27fb0796b2653a1d003cbf6b7a69d8961 commit r11-2058-gb097c7a27fb0796b2653a1d003cbf6b7a69d8961 Author: Szabolcs Nagy <szabolcs.n...@arm.com> Date: Thu Jun 4 09:33:35 2020 +0100 libgcc: fix the handling of return address mangling [PR94891] Mangling, currently only used on AArch64 for return address signing, is an internal representation that should not be exposed via __builtin_return_address return value, __builtin_eh_return handler argument, _Unwind_DebugHook handler argument. Note that a mangled address might not even fit into a void *, e.g. with AArch64 ilp32 ABI the return address is stored as 64bit, so the mangled return address cannot be accessed via _Unwind_GetPtr. This patch changes the unwinder hooks as follows: MD_POST_EXTRACT_ROOT_ADDR is removed: root address comes from __builtin_return_address which is not mangled. MD_POST_EXTRACT_FRAME_ADDR is renamed to MD_DEMANGLE_RETURN_ADDR, it now operates on _Unwind_Word instead of void *, so the hook should work when return address signing is enabled on AArch64 ilp32. (But for that __builtin_aarch64_autia1716 should be fixed to operate on 64bit input instead of a void *.) MD_POST_FROB_EH_HANDLER_ADDR is removed: it is the responsibility of __builtin_eh_return to do the mangling if necessary. 2020-07-13 Szabolcs Nagy <szabolcs.n...@arm.com> libgcc/ChangeLog: PR target/94891 * config/aarch64/aarch64-unwind.h (MD_POST_EXTRACT_ROOT_ADDR): Remove. (MD_POST_FROB_EH_HANDLER_ADDR): Remove. (MD_POST_EXTRACT_FRAME_ADDR): Rename to ... (MD_DEMANGLE_RETURN_ADDR): This. (aarch64_post_extract_frame_addr): Rename to ... (aarch64_demangle_return_addr): This. (aarch64_post_frob_eh_handler_addr): Remove. * unwind-dw2.c (uw_update_context): Demangle return address. (uw_frob_return_addr): Remove.
