Shadowvm: Robust And Comprehensive Dynamic Program Analysis For The Java Platform

Dynamic analysis tools are often implemented using instrumentation, particularly on managed runtimes including the Java Virtual Machine (JVM). Performing instrumentation robustly is especially complex on such runtimes: existing frameworks offer limited coverage and poor isolation, while previous work has shown that apparently innocuous instrumentation can cause deadlocks or crashes in the observed application. This paper describes ShadowVM, a system for instrumentation-based dynamic analyses on the JVM which combines a number of techniques to greatly improve both isolation and coverage. These centre on the offload of analysis to a separate process; we believe our design is the first system to enable genuinely full bytecode coverage on the JVM. We describe a working implementation, and use a case study to demonstrate its improved coverage and to evaluate its runtime overhead.