I don't have such a tool, but there exists tools that may generate test vectors for use with the JTAG interface, so a running program gets stopped at a breakpoint, one or more variables gets forced to known states and the processor gets activated. All automatically. Just to be able to get the code to reach specific branches that are almost impossible to reach with external stimuli. How do you ever reach your "should never reach" error handler, that tries to do some form of repair job in case something really unexpected (such as reaching the default: statement of a switch that already have all known states covered)?

With a normal debugger, it can take quite long time to force execution of a number of such hard-to-reach places before every software release. Having an automatic tool that can play through the states is way nicer.