Know your place: Selectively executing statements based on context

This project provides a way for programmers to insert runtime context-sensitive code into their C programs. The idea is that a program will execute a piece of code only if the program is in a given calling context (i.e., a stack of procedure calls). One way to accomplish this technique is for the program to examine the runtime stack, determine if it matches a given context, then execute the context-sensitive code. Of course, this method is extremely inefficient. A more efficient way to determine the context is to staticly compute a unique “context value” for every possible context along a chain of procedure calls. At runtime, the program compares the actual context number to the desired context number. If these numbers are equivalent, the program executes the context-sensitive code. This facility can be useful in several scenarios: