Im theory you could try counting CPU cycles or something analogous, or algorithmic complexity as the other commenter mentioned. You could also try to measure it in comparison to different code.
Outside of that, and in any practical sense, no you can't. Performance measurements are dependent on the machine as much as the software.
If a car is hardware, and the driver is software, how would you measure the performance of the driver in the different cars? The only way I can think of is if you had 2 different drivers and could compare their times in both cars. If driver 1 is 2x as fast in car 1, and 2x as fast in car 2, you could say driver 1 has a score 2x higher than driver 2.