Is there a way to watch Linux boot as though it was a program compiled with GCC on a Linux environment using the -g switch so, say, I can step through the entire boot sequence from GRUB onwards, choosing to step through at C source level or assembly when necessary/desirable, by using GDB or a GDB-like tool?

I suspect it would require a virtual machine at least, to watch the boot on a host environment. Any elaboration on this topic of observing a boot would be appreciated!