[openasocket]

That's a good point, you can definitely optimize. I'd be curious how far you could go using static analysis. Assuming no recursion, function pointers, dynamic linking, etc; can you optimize to the point that you use as little memory as a stack approach would? I think you ALMOST can! The only blocker would be specific call patterns that would require a lot of memory, but are unreachable. That's where the halting problem hits.

You just make a call graph where the nodes are functions and directed edges indicate which function calls which. Without recursion function pointers and the like you can compute this exactly and this forms a DAG. Each node is given a weight, which is the amount of local memory that function needs. Start at the entry point function, and compute the longest distance path (using the node weight).