Abstract. Configurable software verification is a recent concept for expressing different program analysis and model checking approaches in one single formalism. This paper presents CPAchecker, a tool and framework that aims at easy integration of new verification components. Every abstract domain, together with the corresponding operations, implements the interface of configurable program analysis (CPA). The main algorithm is configurable to perform a reachability analysis on arbitrary combinations of existing CPAs. In software verification, it takes a considerable amount of effort to convert a verification idea into actual experimental results -we aim at accelerating this process. We hope that researchers find it convenient and productive to implement new verification ideas and algorithms using this flexible and easy-to-extend platform, and that it advances the field by making it easier to perform practical experiments. The tool is implemented in Java and runs as command-line tool or as Eclipse plug-in. CPAchecker implements CPAs for several abstract domains. We evaluate the efficiency of the current version of our tool on software-verification benchmarks from the literature, and compare it with other state-of-the-art model checkers.CPAchecker is an open-source toolkit and publicly available. OverviewThe field of software verification is a fast growing area, and researchers contribute new ideas and approaches with enormous pace. The more new approaches are discovered, the more difficult it is to understand the essential insight or the fundamental difference that makes a new approach good and better. Experimental evaluation is often a deciding factor for whether or not a new approach is considered an advancement of the field. But it requires a considerable engineering effort to actually build the software infrastructure for evaluating verification algorithms. Adapting a suitable parser front-end and transforming the abstract syntax tree into a format that is convenient for verification algorithms is one example. The interaction with a theorem prover is yet another issue that needs to be considered. There are successful approaches in program analysis as well as in model checking, but these techniques are rarely combined; the reason is that it is indeed extremely difficult to combine them. Most published approaches are not even comparable, because the choice of the parser front-end, the choice of the theorem prover, and the choice of the pointer-alias analysis algorithm in the corresponding tool implementation, considerably influence the performance and precision of the new verification algorithm. When evaluating a performance comparison of two approaches, it is often difficult to identify what the new approach contributes and what is due to the different environment. In practice, it was so far extremely difficult to perform an experimental performance evaluation of one component while keeping all other components constant.Configurable program analysis (CPA) provides a conceptual basis for expressing different ve...

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Abstract-Product-line technology is increasingly used in mission-critical and safety-critical applications. Hence, researchers are developing verification approaches that follow different strategies to cope with the specific properties of product lines. While the research community is discussing the mutual strengths and weaknesses of the different strategies-mostly at a conceptual level-there is a lack of evidence in terms of case studies, tool implementations, and experiments. We have collected and prepared six product lines as subject systems for experimentation. Furthermore, we have developed a modelchecking tool chain for C-based and Java-based product lines, called SPLVERIFIER, which we use to compare sample-based and family-based strategies with regard to verification performance and the ability to find defects. Based on the experimental results and an analytical model, we revisit the discussion of the strengths and weaknesses of product-line-verification strategies.

We have extended the software model checker BLAST to automatically generate test suites that guarantee full coverage with respect to a given predicate. More precisely, given a C program and a target predicate Ô, BLAST determines the set Ä of program locations which program execution can reach with Ô true, and automatically generates a set of test vectors that exhibit the truth of Ô at all locations in Ä. We have used BLAST to generate test suites and to detect dead code in C programs with up to 30 K lines of code. The analysis and test-vector generation is fully automatic (no user intervention) and exact (no false positives).

In automatic software verification, we have observed a theoretical convergence of model checking and program analysis. In practice, however, model checkers are still mostly concerned with precision, e.g., the removal of spurious counterexamples; for this purpose they build and refine reachability trees. Lattice-based program analyzers, on the other hand, are primarily concerned with efficiency. We designed an algorithm and built a tool that can be configured to perform not only a purely tree-based or a purely lattice-based analysis, but offers many intermediate settings that have not been evaluated before. The algorithm and tool take one or more abstract interpreters, such as a predicate abstraction and a shape analysis, and configure their execution and interaction using several parameters. Our experiments show that such customization may lead to dramatic improvements in the precision-efficiency spectrum.

Abstract-A software product line is a set of software products that are distinguished in terms of features (i.e., end-user-visible units of behavior). Feature interactions -situations in which the combination of features leads to emergent and possibly critical behavior-are a major source of failures in software product lines. We explore how feature-aware verification can improve the automatic detection of feature interactions in software product lines. Feature-aware verification uses product-line-verification techniques and supports the specification of feature properties along with the features in separate and composable units. It integrates the technique of variability encoding to verify a product line without generating and checking a possibly exponential number of feature combinations. We developed the tool suite SPLVERIFIER for feature-aware verification, which is based on standard model-checking technology. We applied it to an e-mail system that incorporates domain knowledge of AT&T. We found that feature interactions can be detected automatically based on specifications that have only local knowledge.

The next generation of networked mechatronic systems will be characterized by complex coordination and structural adaptation at run-time. Crucial safety properties have to be guaranteed for all potential structural configurations. Testing cannot provide safety guarantees, while current model checking and theorem proving techniques do not scale for such systems. We present a verification technique for arbitrarily large multi-agent systems from the mechatronic domain, featuring complex coordination and structural adaptation. We overcome the limitations of existing techniques by exploiting the local character of structural safety properties. The system state is modeled as a graph, system transitions are modeled as rule applications in a graph transformation system, and safety properties of the system are encoded as inductive invariants (permitting the verification of infinite state systems). We developed a symbolic verification procedure that allows us to perform the computation on an efficient BDD-based graph manipulation engine, and we report performance results for several examples.

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