https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80556
--- Comment #65 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-11 branch has been updated by Iain D Sandoe <ia...@gcc.gnu.org>: https://gcc.gnu.org/g:94c9c6acdc14de186abe4ea59c54920fbfb60beb commit r11-9878-g94c9c6acdc14de186abe4ea59c54920fbfb60beb Author: Iain Sandoe <i...@sandoe.co.uk> Date: Sat Sep 18 23:38:53 2021 +0100 Darwin: Rework handling for unwinder code in libgcc_s and specs [PR80556]. This addresses a long-standing problem where a work-around for an unwinder issue (also a regression) regresses other functionality. The patch replaces several work-arounds with a fix for PR80556 and a work-around for PR88590. * The fix for PR80556 requires a bump to the SO name for libgcc_s, since we need to remove the unwinder symbols from it. This would trigger PR88590 hence the work-around for that. * We weaken the symbols for emulated TLS support so that it is possible for a DSO linked with static-libgcc to interoperate with a DSO linked with libgcc_s. Likewise main exes. * We remove all the gcc-4.2.1 era stubs machinery and workarounds. * libgcc is always now linked ahead of libc, which avoids fails where the libc (libSystem) builtins implementations are not up to date. * The unwinder now always comes from the system - for Darwin9 from /usr/lib/libgcc_s.1.dylib - for Darwin10 from /usr/lib/libSystem.dylib - for Darwin11+ from /usr/lib/system/libunwind.dylib. We still insert a shim on Darwin10 to fix an omitted unwind function, but the underlying unwinder remains the system one. * The work-around for PR88590 has two parts (1) we always link libgcc from its convenience lib on affected system versions (avoiding the need to find the DSO path); (2) we add and export the emutls functions from DSOs - this makes a relatively small (20k) addition to a DSO. These can be backed out when a proper fix for PR88590 is committed. For distributions that wish to install a libgcc_s.1.dylib to satisfy linkage from exes that linked against the stubs can use a reexported libgcc_s.1.1 (since that contains all the symbols that were previously exported via the stubs). The replacement libgcc_s.1 forwards the symbols from the new SO. In order to support DYLD_LIBRARY_PATH on systems (where it works) we forward the libSystem unwinder symbols from 10.7+ and a compiler-local version of the libgcc unwinder on earlier. For macOS 10.4 to 10.6 this is 'bug-compatible' with existing uses. For 10.7+ the behaviour will now actually be correct. Backported from commits d4943ce939d9654932624b9ece24c3a474ae4157, 7add7f7bb3d35726a0c45322ffdbbab2bbf6a348, b504917e43b9a559c9ac779e08784ad412125f2e, 32731fa5b0abf092029b8e2be64319b978bda514, 574c09da48a5a0ff4c32dd4577eaf65bac8c94a0 and c18ddb05b0391a397f8882fc6a12a1bab7e0df52 Signed-off-by: Iain Sandoe <i...@sandoe.co.uk> gcc/ChangeLog: PR target/80556 * config/darwin-driver.c (darwin_driver_init): Handle exported symbols and symbol lists (suppress automatic export of the TLS symbols). * config/darwin.c (darwin_rename_builtins): Remove workaround. * config/darwin.h (LINK_GCC_C_SEQUENCE_SPEC): Likewise. (REAL_LIBGCC_SPEC): Handle revised library uses. * config/darwin.opt (nodefaultexport): New. * config/i386/darwin.h (PR80556_WORKAROUND): Remove. * config/i386/darwin32-biarch.h (PR80556_WORKAROUND): Likewise. * config/i386/darwin64-biarch.h (PR80556_WORKAROUND): Likewise. libgcc/ChangeLog: * config.host: Add weak emutls crt to the extra_parts. (*-*-darwin*): Add logic to build a shared unwinder library for Darwin8-10. Add shim declaration header to powerpc*-darwin builds. * config/i386/darwin-lib.h (DECLARE_LIBRARY_RENAMES): Remove workaround. * config/libgcc-libsystem.ver: Add exclude list for the system- provided unwinder. * config/t-slibgcc-darwin: Bump SO version, remove stubs code. Build a legacy libgcc_s.1 and the supporting pieces (all FAT libs). * config/t-darwin-ehs: Add dependencies to the shared unwinder objects. Add dependency on unwind.h. * config/t-darwin: Reorganise the EH fragments to place them for inclusion in a shared EH lib. Add libgcc_tm.h to the dependencies for darwin10-unwind-find-enc-func. * config/i386/libgcc-darwin.10.4.ver: Removed. * config/i386/libgcc-darwin.10.5.ver: Removed. * config/rs6000/libgcc-darwin.10.4.ver: Removed. * config/rs6000/libgcc-darwin.10.5.ver: Removed. * config/i386/t-darwin: Build legacy libgcc_s.1. * config/rs6000/t-darwin: Likewise. * config/rs6000/t-darwin-ehs: Remove dependency on the powerpc end file. Add darwin-fallback.o. gcc/testsuite/ChangeLog: * gcc.dg/torture/fp-int-convert-timode-3.c: Remove XFAIL. * gcc.dg/torture/fp-int-convert-timode-4.c: Likewise.
