A Heap Model for Java Bytecode to Support Separation Logic

Memory usage analysis is an important problem for resource-constrained mobile devices, especially under mission- or safety-critical circumstances. Program codes running on or being downloaded into such devices are often available in low-level bytecode forms. We propose in this paper a formal heap model for Java bytecode language, on top of which we can then provide separation logic support for further memory usage verification. Our low-level heap model for Java bytecode would allow us to reason about the size and alignment properties of primitive values stored in the heap. To support type-related reasoning such as guaranteeing type and alignment safety, this model is also lifted with both base types and user-defined classes. Based on such model, we have also defined a separation logic proof system whose assertions are interpreted using the lifted heap with types. We envision, with further extension, the system would provide good support for memory usage analysis and verification for mobile devices.