Sorry, I do not understand.

Each line of what?

In the benchmark listed on their website

are they comparing how long it takes for each platform P to compile v sources or P sources ?

If you mean the table under "For comparison, space and time required to build each compiler", I think, that it is about what each compiler took in time and disk space to compile itself, on the same hardware, so it is about P compiling P sources.

V can not compile C or Go, Go can not compile C, and C compilers can not compile V or Go, so it can not be otherwise.