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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/108994] [13 Regression] LLVM JIT segfaults in libgcc after upgrading from gcc 12.2.1 to 13.0.1 since r13-2706-g6e80a1d164d1f9 Date: Tue, 14 Mar 2023 07:04:55 +0000 [thread overview] Message-ID: <bug-108994-4-htmjDvBW4c@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-108994-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108994 --- Comment #18 from Jakub Jelinek <jakub at gcc dot gnu.org> --- It is a fundamental assumption that the FDE/CIE chain is zero terminated, after all, all the registration APIs (__register_frame_table, __register_frame_info_table, __register_frame_info_table_bases) take just a begin pointer, not a begin and end pointer nor begin + count or something similar, nor assume there is just one FDE (after all, a FDE needs some CIE, so there would need to be a routine that expects exactly two or something similar). When not using .eh_frame_hdr (which is used most of the time on glibc since end of 2001 when I've added it and somewhat later on Solaris etc.), crtbegin.o/crtend.o ensures this, crtbegin.o provides a label at the start of .eh_frame and is linked first among the objects: /* Stick a label at the beginning of the frame unwind info so we can register and deregister it with the exception handling library code. */ STATIC EH_FRAME_SECTION_CONST char __EH_FRAME_BEGIN__[] __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4))) = { }; while crtend.o provides the zero termination: /* Terminate the frame unwind info section with a 4byte 0 as a sentinel; this would be the 'length' field in a real FDE. */ # if __INT_MAX__ == 2147483647 typedef int int32; # elif __LONG_MAX__ == 2147483647 typedef long int32; # elif __SHRT_MAX__ == 2147483647 typedef short int32; # else # error "Missing a 4 byte integer" # endif STATIC EH_FRAME_SECTION_CONST int32 __FRAME_END__[] __attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(__alignof__(int32)))) = { 0 }; and is linked last. I believe LLVM does the same thing in compiler-rt/lib/crt/crtbegin.c and compiler-rt/lib/crt/crtend.c . If you readelf -wf any_binary_or_library it should show 00330010 ZERO terminator line (with whatever address) at the end.
next prev parent reply other threads:[~2023-03-14 7:04 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-02 18:15 [Bug libgcc/108994] New: LLVM JIT segfaults in libgcc after upgrading from gcc 12.2.1 to 13.0.1 tstellar at redhat dot com 2023-03-02 18:19 ` [Bug libgcc/108994] [13 Regression] " redi at gcc dot gnu.org 2023-03-02 19:15 ` pinskia at gcc dot gnu.org 2023-03-02 19:19 ` tstellar at redhat dot com 2023-03-02 20:09 ` pinskia at gcc dot gnu.org 2023-03-03 3:13 ` tstellar at redhat dot com 2023-03-03 3:29 ` pinskia at gcc dot gnu.org 2023-03-03 7:39 ` tstellar at redhat dot com 2023-03-03 7:45 ` pinskia at gcc dot gnu.org 2023-03-03 7:46 ` pinskia at gcc dot gnu.org 2023-03-03 7:47 ` redi at gcc dot gnu.org 2023-03-03 8:45 ` [Bug target/108994] " jakub at gcc dot gnu.org 2023-03-03 18:37 ` tstellar at redhat dot com 2023-03-04 0:15 ` tstellar at redhat dot com 2023-03-06 12:37 ` [Bug target/108994] [13 Regression] LLVM JIT segfaults in libgcc after upgrading from gcc 12.2.1 to 13.0.1 since r13-2706-g6e80a1d164d1f9 marxin at gcc dot gnu.org 2023-03-09 16:29 ` tstellar at redhat dot com 2023-03-09 18:50 ` tstellar at redhat dot com 2023-03-10 17:18 ` jakub at gcc dot gnu.org 2023-03-10 17:37 ` tstellar at redhat dot com 2023-03-14 5:41 ` tstellar at redhat dot com 2023-03-14 7:04 ` jakub at gcc dot gnu.org [this message] 2023-03-14 17:22 ` tstellar at redhat dot com 2023-03-14 18:08 ` pinskia at gcc dot gnu.org
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