Isn't it the case that for the money that will go in porting (and
testing :-O) you could actually ensure that i.e. GNAT, or your current
toolchain of choice, will survive in good shape?
But then, don't worry: there seems to be some Ada research interest
...in China, there were some papers, it is not unreasonable to think
that they are tip of an iceberg. So if not in US Defense systems, Ada
will survive in Chinese ones. So there is really no need to worry about.
What were we discussing? A web dating service? Oh no! - a critical
defense system. So the #1 question is: does the commander realize that
C++ is not nearly as good for this system as Ada?