Abstract: A source computer program is analyzed and transformed into a directed graph file comprising a function list file, listing all functions (nodes) in the directed graph file, and a function call list file, listing all calls between said functions (arcs). A hierarchical graph analysis (HGA) function: calculates a "node reach" for each node--comprising the set of all nodes which may be reached from the node in question; produces a node display threshold value--indicating the maximum node reach to be displayed; and uses the node display threshold value to produce an HGA directed graph--comprising only those nodes to be displayed. Finally, a display function displays the HGA directed graph. Optionally, the node display threshold value may be modified after the display, and a new HGA directed graph produced and displayed.