GWL This is an example of building a static call graph (actually a tree) for a single routine. It builds a tree with the routine as the only child off of the root. A node's children are its callers (note, there are multiple paths to a caller, a caller is only inserted once in the tree). It would be more correct to use a graph, but my objective was just to find "top level" callers and I really did not care about the path.