dim added subscribers: emaste, jrtc27, dim. dim added a comment. FWIW, this commit turned out to break the FreeBSD dns/bind916 port, see https://bugs.freebsd.org/259921.
The short story is that the bind9 code on and after this line: https://gitlab.isc.org/isc-projects/bind9/-/blob/main/lib/isc/log.c#L1525 gets changed from something like: .Ltmp661: #DEBUG_VALUE: isc_log_doit:category_channels <- $r12 .loc 3 0 58 # log.c:0:58 xorl %eax, %eax testl %r15d, %r15d setg %al movl %r15d, %ecx negl %ecx movq %rcx, -840(%rbp) # 8-byte Spill leaq 8328(%r13), %rcx #DEBUG_VALUE: isc_log_doit:matched <- 0 movq %rcx, -808(%rbp) # 8-byte Spill .Ltmp662: .loc 3 1552 25 is_stmt 1 # log.c:1552:25 to using a relative lookup table: .Ltmp661: #DEBUG_VALUE: isc_log_doit:category_channels <- $r12 .loc 3 0 58 # log.c:0:58 xorl %eax, %eax testl %r15d, %r15d setg %al movl %r15d, %edx negl %edx leaq reltable.isc_log_doit(%rip), %rcx movq %rdx, -848(%rbp) # 8-byte Spill movslq (%rcx,%rdx,4), %rdx addq %rcx, %rdx movq %rdx, -840(%rbp) # 8-byte Spill leaq 8328(%r13), %rcx #DEBUG_VALUE: isc_log_doit:matched <- 0 movq %rcx, -808(%rbp) # 8-byte Spill .Ltmp662: .loc 3 1552 25 is_stmt 1 # log.c:1552:25 However, the value of `%rcx` at the `movslq (%rcx,%rdx,4), %rdx` statement becomes -2, so it attempts to access data before `reltable.isc_log_doit`. As that is in `.rodata`, this leads to a segfault. The current working theory is that some code is hoisted out of the do-while loop starting at https://gitlab.isc.org/isc-projects/bind9/-/blob/main/lib/isc/log.c#L1531, in particular the `[-level]` accesses on lines 1613 and 1843: snprintf(level_string, sizeof(level_string), "%s: ", log_level_strings[-level]); ... } else { syslog_level = syslog_map[-level]; } but maybe these negative offsets confuse the lookup table converter? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D94355/new/ https://reviews.llvm.org/D94355 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
