To my understanding, the value of GetElementPtr can always be expressed by `val = base + index_1 * length_1 + index_2 * length_2 + ...`

where `index_i`

is the i’th integer index and `length_i`

is the i’th element length

The point that I need help with is that how to retrieve these information, I’ve searched the documentation and internet, and asked GPT, no one will give out an general answer.