Visualizing call graphs

Developers navigate and reason about call graphs throughout investigation and debugging activities. This is often difficult: developers can spend tens of minutes answering a single question, get lost and disoriented, and erroneously make assumptions, causing bugs. To address these problems, we designed a new form of interactive call graph visualization - REACHER. Instead of leaving developers to manually traverse the call graph, REACHER lets developers search along control flow. The interactive call graph visualization encodes a number of properties that help developers answer questions about causality, ordering, type membership, repetition, choice, and other relationships. And developers remain oriented while navigating. To evaluate REACHER'S benefits, we conducted a lab study in which 12 participants answered control flow questions. Compared to an existing IDE, participants with REACHER were over 5 times more successful in significantly less time. All enthusiastically preferred REACHER, with many positive comments.