https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63788
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Supposed BUILT_IN_OBJECT_SIZE builtin decl isn't wired. So, either you need to avoid instrumenting -fsanitize=object-size, if it is NULL, or e.g. initialize_sanitizer_builtins needs to create the __builtin_object_size builtin if it is not created by the FE. As that built-in isn't a sanitizer built-in, thus not in sanitizer.def, supposedly you could just copy the: DEF_GCC_BUILTIN (BUILT_IN_OBJECT_SIZE, "object_size", BT_FN_SIZE_CONST_PTR_INT, ATTR_PURE_NOTHROW_LEAF_LIST) line below #include "sanitizer.def" in asan.c.
