I would note that determining maximum stack usage is similar to the halting problem in some cases. One must carefully restrict how the program is structured for this analysis to be valid. As is stated, any sort of recursion or mutually dependent functions are out, and the use of function pointers could also cause issues.

This approach provides a good baseline. However, I'd highly recommend empirical testing as well. For example, create a sufficiently large stack, initialize the stack with a known bit pattern and then check the high water mark after fully exercising the program.