The distinctions are quite arbitrary since there currently isn't anything like a size-competition for compilers, but if forced to make categories, I'd consider <1kLoC to be "tiny" and <10kLoC "small".

In contrast, GCC is nearing 10MLoC - 4 orders of magnitude difference - and its C parser alone is >10kLoC: https://github.com/gcc-mirror/gcc/blob/master/gcc/c/c-parser...