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

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.