1 Variably Interprocedural Program Analysis for RuntimeError Detection

ABSTRACT This paper describes an analysis approach based on a combination of static and dynamic techniques to find run-time errors in Java code. It uses symbolic execution to find constraints under which an error (e.g., a null pointer dereference, array out of bounds access, or assertion violation) may occur and then solves these constraints to find test inputs that may expose the error. It only alerts the user to the possibility of a real error when it detects the expected exception during a program run. The analysis is customizable in two important ways. First, we can adjust how deeply to follow calls from each top-level method. Second, we can adjust the path termination condition for the symbolic execution engine to be either a bound on the path condition length or a bound on the number of times each instruction can be revisited. We evaluated the tool on a set of benchmarks from the literature as well as a number of real-world systems that range in size from a few thousand to 50,000 lines of code. The tool discovered all known errors in the benchmarks (as well as some not previously known) and reported on average 8 errors per 1000 lines of code for the industrial examples. In both cases the interprocedural call depth played little role in the error detection. That is, an intraprocedural analysis seems adequate for the class of errors we detect