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Abstract. We present a new type system for an object-oriented (OO) language that characterizes the sizes of data structures and the amount of heap memory required to successfully execute methods that operate on these data structures. Key components of this type system include type assertions that use symbolic Presburger arithmetic expressions to capture data structure sizes, the effect of methods on the data structures that they manipulate, and the amount of memory that methods allocate and deallocate. For each method, we conservatively capture the amount of memory required to execute the method as a function of the sizes of the method's inputs. The safety guarantee is that the method will never attempt to use more memory than its type expressions specify. We have implemented a type checker to verify memory usages of OO programs. Our experience is that the type system can precisely and effectively capture memory bounds for a wide range of programs.

Embedded systems are becoming more widely used but these systems are often resource constrained. Programming models for these systems should take into formal consideration resources such as stack and heap. In this paper, we show how memory resource bounds can be inferred for assembly-level programs. Our inference process captures the memory needs of each method in terms of the symbolic values of its parameters. For better precision, we infer path-sensitive information through a novel guarded expression format. Our current proposal relies on a Presburger solver to capture memory requirements symbolically, and to perform fixpoint analysis for loops and recursion. Apart from safety in memory adequacy, our proposal can provide estimate on memory costs for embedded devices and improve performance via fewer runtime checks against memory bound.

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One promising approach to verifying heap-manipulating programs is based on user-defined inductive predicates in separation logic. This approach can describe data structures with complex invariants and sound reasoning based on unfold/fold. However, an important component towards more expressive program verification is the use of lemmas that can soundly relate predicates beyond their original definitions. This paper outlines a new automatic mechanism for proving and applying user-specified lemmas under separation logic.

Abstract. We present a new modular shape analysis that can synthesize heap memory specification on a per method basis. We rely on a second-order biabduction mechanism that can give interpretations to unknown shape predicates. There are several novel features in our shape analysis. Firstly, it is grounded on second-order bi-abduction. Secondly, we distinguish unknown pre-predicates in pre-conditions, from unknown post-predicates in post-condition; since the former may be strengthened, while the latter may be weakened. Thirdly, we provide a new heap guard mechanism to support more precise preconditions for heap specification. Lastly, we formalise a set of derivation and normalization rules to give concise definitions for unknown predicates. Our approach has been proven sound and is implemented on top of an existing automated verification system. We show its versatility in synthesizing a wide range of intricate shape specifications.