COSTA: Design and Implementation of a Cost and Termination Analyzer for Java Bytecode

This paper describes the architecture of costa, an abstract interpretation based cost and termination analyzer for Java bytecode. The system receives as input a bytecode program, (a choice of) a resource of interest and tries to obtain an upper bound of the resource consumption of the program. costa provides several non-trivial notions of cost, as the consumption of the heap, the number of bytecode instructions executed and the number of calls to a specific method. Additionally, costa tries to prove termination of the bytecode program which implies the boundedness of any resource consumption. Having cost and termination together is interesting, as both analyses share most of the machinery to, respectively, infer cost upper bounds and to prove that the execution length is always finite (i.e., the program terminates). We report on experimental results which show that costa can deal with programs of realistic size and complexity, including programs which use Java libraries. To the best of our knowledge, this system provides for the first time evidence that resource usage analysis can be applied to a realistic object-oriented, bytecode programming language.