ubsan

Recent versions of GCC and Clang feature Undefined Behavior Sanitizer (UBSan) which is a compile flag ( -fsanitize=undefined ) that adds runtime instrumentation code. On errors, a warning such as this one is shown: packet-ber.c:1917:23: runtime error: left shift of 54645397829836991 by 8 places cannot be represented in type 'long int' Now I would like to debug this and get a debug break on said line. For Address Sanitizer (ASAN) there is ASAN_OPTIONS=abort_on_error=1 which results in a fatal error that is catchable. The only UBSan option that seems usable is UBSAN_OPTIONS=print_stacktrace=1

Today I have read an article about GCC Undefined Behavior Sanitizer (ubsan) . However, when I follow steps there (add -fsanitize=undefined to my code), the compiler (GCC 4.9.2 on Ubuntu 15.04) says that some references are not defined: ||=== Build: Debug in Entangle (compiler: GNU GCC Compiler) ===| obj/Debug/EntangleApp.o||In function `EntangleApp::OnInit()':| /home/ilya/Projects/Entangle/EntangleApp.cpp|31|undefined reference to `__ubsan_handle_type_mismatch'| /home/ilya/Projects/Entangle/EntangleApp.cpp|31|undefined reference to `__ubsan_handle_load_invalid_value'| /home/ilya/Projects