Compiling Link dependent targets in parallel

Hi,

Currently for link dependent targets, say if A depends on B, for A to start
compiling the compilation and linking of B has to be completed first. But
given that compilation of both the targets is independent of each other,
isn't there a way where A and B compile in parallel and this wait happens
only at Link Time. i.e

-> A's compilation starts
-> B's compilation starts (in parallel)
-> if A finishes first it waits for B to finish(for linking), but if B
finishes first A doesn't have to wait

this will save a lot of time that target A spends just waiting for B to
complete, which could have used to compile A in parallel as well.

Thanks,
Shubham