A Non-repetitive Logic for Verification of Dynamic Memory with Explicit Heap Conjunction and Disjunction

In this paper, we review existing points-to Separation Logics for dynamic memory reasoning and we find that different usages of heap separation tend to be an obstacle. Hence, two total and strict spatial heap operations are proposed upon heap graphs, for conjunction and disjunction -- similar to logical conjuncts. Heap conjunction implies that there exists a free heap vertex to connect to or an explicit destination vertex is provided. Essentially, Burstall's properties do not change. By heap we refer to an arbitrary simple directed graph, which is finite and may contain composite vertices representing class objects. Arbitrary heap memory access is restricted, as well as type punning, late class binding and further restrictions. Properties of the new logic are investigated, and as a result group properties are shown. Both expecting and superficial heaps are specifiable. Equivalence transformations may make denotated heaps inconsistent, although those may be detected and patched by the two generic linear canonization steps presented. The properties help to motivate a later full introduction of a set of equivalences over heap for future work. Partial heaps are considered as a useful specification technique that help to reduce incompleteness issues with specifications. Finally, the logic proposed may be considered for extension for the Object Constraint Language.Comment: 9 pages, 7 figure

A Logical Programming Language as an Instrument for Specifying and Verifying Dynamic Memory

This work proposes a Prolog-dialect for the found and prioritised problems on expressibility and automation. Given some given C-like program, if dynamic memory is allocated, altered and freed on runtime, then a description of desired dynamic memory is a heap specification. The check of calculated memory state against a given specification is dynamic memory verification. This contribution only considers formal specification and verification in a Hoare calculus. Issues found include: invalid assignment, (temporary) unavailable data in memory cells, excessive memory allocation, (accidental) heap alteration in unexpected regions and others. Excessive memory allocation is nowadays successfully resolved by memory analysers like Valgrind. Essentially, papers in those areas did not bring any big breakthrough. Possible reasons may also include the decrease of tension due to more available memory and parallel threads. However, starting with Apt, problems related to variable modes have not yet been resolved -- neither entirely nor in an acceptable way. Research contributions over the last decades show again and again that heap issues remain and remain complex and still important. A significant contribution was reached in 2016 by Peter O'Hearn, who accepted the G\"{o}del prize for his parallel approach on a spatial heap operation.Comment: 209 pages, 97 figures, 6 appendice