Can software be written (for some specific programming language, platform, etc.) that will inform a user of exactly how many times the relevant machine-level instruction pointers change value during the execution of a program? Is such software already available?
Yes, this is possible, at least on many processors. The key is the use of hardware performance counters.
I'm not sure if there's a good API for accessing these. But tools such as OProfile can do this kind of performance monitoring for you.