This paper studies how to verify the conformity of a program with its specification and proposes a novel constraint-programming framework for bounded program verification (CPBPV). The CPBPV framework uses constraint stores to represent the specification and the program and explores execution paths nondeterministically. The input program is partially correct if each constraint store so produced implies the post-condition. CPBPV does not explore spurious execution paths as it incrementally prunes execution paths early by detecting that the constraint store is not consistent. CPBPV uses the rich language of constraint programming to express the constraint store. Finally, CPBPV is parametrized with a list of solvers which are tried in sequence, starting with the least expensive and less general. Experimental results often produce orders of magnitude improvements over earlier approaches, running times being often independent of the variable domains. Moreover, CPBPV was able to detect subtle errors in some programs while other frameworks based on model checking have failed.
Université de Nice–Sophia Antipolis（尼斯-索菲亚安提波利斯大学）；Brown University（布朗大学）
This report describes experimental results for a set of benchmarks on program verification. It compares the capabilities of CPBVP "Constraint Programming framework for Bounded Program Verification" [4] with the following frameworks: ESC/Java, CBMC, Blast, EUREKA and Why.
Many approaches for verifying input-output properties of neural networks have been proposed recently. However, existing algorithms do not scale well to large networks. Recent work in the field of model compression studied binarized neural networks (BNNs), whose parameters and activations are binary. BNNs tend to exhibit a slight decrease in performance compared to their full-precision counterparts, but they can be easier to verify. This paper proposes a simple mixed integer programming formulation for BNN verification that leverages network structure. We demonstrate our approach by verifying p…
We present an approach for the verification of feed-forward neural networks in which all nodes have a piece-wise linear activation function. Such networks are often used in deep learning and have been shown to be hard to verify for modern satisfiability modulo theory (SMT) and integer linear programming (ILP) solvers. The starting point of our approach is the addition of a global linear approximation of the overall network behavior to the verification problem that helps with SMT-like reasoning over the network behavior. We present a specialized verification algorithm that employs this approxim…
Ladder Logics is a programming language standardized in IEC 61131-3 and widely used for programming industrial Programmable Logic Controllers (PLC). A PLC program consists of inputs (whose values are given at runtime by factory sensors), outputs (whose values are given at runtime to factory actuators), and the logical expressions computing output values from input values. Due to the graphical form of Ladder programs, and the amount of inputs and outputs in typical industrial programs, debugging such programs is time-consuming and error-prone. We present, in this paper, a Why3-based tool protot…
In this paper, we present linear programming-based sufficient conditions, some of them polynomial-time, to establish the liveness and memory boundedness of general dataflow process networks. Furthermore, this approach can be used to obtain safe upper bounds on the size of the channel buffers of such a network.
Traditional software engineering programming paradigms are mostly object or procedure oriented, driven by deterministic algorithms. With the advent of deep learning and cognitive sciences there is an emerging trend for data-driven programming, creating a shift in the programming paradigm among the software engineering communities. Visualizing and interpreting the execution of a current large scale data-driven software development is challenging. Further, for deep learning development there are many libraries in multiple programming languages such as TensorFlow (Python), CAFFE (C++), Theano (Py…
In the cloud, the technology is used on-demand without the need to install anything on the desktop. Software as a Service is one of the many cloud architectures. The PubSub messaging pattern is a cloud-based Software as a Service solution used in complex systems, especially in the notifications part where there is a need to send a message from one unit to another single unit or multiple units. Haskell is a generic typed programming language which has pioneered several advanced programming language features. Based on the lambda calculus system, it belongs to the family of functional programming…
With the progress in deductive program verification research, new tools and techniques have become available to support design-by-contract reasoning about non-trivial programs written in widely-used programming languages. However, deductive program verification remains an activity for experts, with ample experience in programming, specification and verification. We would like to change this situation, by developing program verification techniques that are available to a larger audience. In this paper, we present how we developed prototypal program verification support for Snap!. Snap! is a vis…
Algorithmic and data refinement are well studied topics that provide a mathematically rigorous approach to gradually introducing details in the implementation of software. Program refinements are performed in the context of some programming language, but mainstream languages lack features for recording the sequence of refinement steps in the program text. To experiment with the combination of refinement, automated verification, and language design, refinement features have been added to the verification-aware programming language Dafny. This paper describes those features and reflects on some …
Rule-based policy and contract systems have rarely been studied in terms of their software engineering properties. This is a serious omission, because in rule-based policy or contract representation languages rules are being used as a declarative programming language to formalize real-world decision logic and create IS production systems upon. This paper adopts an SE methodology from extreme programming, namely test driven development, and discusses how it can be adapted to verification, validation and integrity testing (V&V&I) of policy and contract specifications. Since, the test-driven appr…
We review some results regarding specification, programming and verification of different classes of distributed systems which stemmed from the research of the Concurrency and Mobility Group at University of Firenze. More specifically, we examine the distinguishing features of network-aware programming, service-oriented computing, autonomic computing, and collective adaptive systems programming. We then present an overview of four different languages, namely Klaim, Cows, Scel and AbC. For each language, we discuss design choices, present syntax and semantics, show how the different formalisms …
These proceedings contain the papers presented at the 11th International Workshop on Automated Specification and Verification of Web Systems (WWV 2015), which was held on 23 June 2015 in Oslo, Norway, as a satellite workshop of the 20th International Symposium on Formal Methods (FM 2015). WWV is a yearly interdisciplinary forum for researchers originating from the following areas: declarative, rule-based programming, formal methods, software engineering and web-based systems. The workshop fosters the cross-fertilisation and advancement of hybrid methods from such areas.
Many Program Verification and Synthesis problems of interest can be modeled directly using Horn clauses and many recent advances in the CLP and CAV communities have centered around efficiently solving problems presented as Horn clauses. The HCVS series of workshops aims to bring together researchers working in the two communities of Constraint/Logic Programming (e.g., ICLP and CP), Program Verification (e.g., CAV, TACAS, and VMCAI), and Automated Deduction (e.g., CADE, IJCAR), on the topic of Horn clause based analysis, verification, and synthesis. Horn clauses for verification and synthesis h…
These proceedings contain the papers presented at the 10th International Workshop on Automated Specification and Verification of Web Systems (WWV 2014), which was held on 18 July 2014 in Vienna, Austria, as a satellite workshop of the Federated Logic Conference (FLoC 2014), associated to the 7th International Joint Conference on Automated Reasoning (IJCAR 2014), as part of the Vienna Summer of Logic (VSL 2014). WWV is a yearly workshop that aims at providing an interdisciplinary forum to facilitate the cross-fertilization and the advancement of hybrid methods that exploit concepts and tools dr…
This volume contains the post-proceedings of the second Workshop on Verification of Objects at RunTime EXecution (VORTEX 2018) that was held in Amsterdam, co-located with the European Conference on Object-Oriented Programming (ECOOP 2018) and the ACM SIGSOFT International Symposium on Software Testing and Analysis (ISSTA 2018). Runtime verification is an approach to software verification which is concerned with monitoring and analysis of software and hardware system executions. Recently, it has gained more consensus as an effective and promising approach to ensure software reliability, bridgin…
Automated software verification is a very active field of research which has made enormous progress both in theoretical and practical aspects. Recently, an important amount of research effort has been put into applying these techniques on top of mainstream programming languages. These languages typically provide powerful features such as reflection, aliasing and polymorphism which are handy for practitioners but, in contrast, make verification a real challenge. In this work we present Pest, a simple experimental, while-style, multiprocedural, imperative programming language which was conceived…
Verification conditions (VCs) are logical formulas whose satisfiability guarantees program correctness. We consider VCs in the form of constrained Horn clauses (CHC) which are automatically generated from the encoding of (an interpreter of) the operational semantics of the programming language. VCs are derived through program specialization based on the unfold/fold transformation rules and, as it often happens when specializing interpreters, they contain unnecessary variables, that is, variables which are not required for the correctness proofs of the programs under verification. In this paper…
In the last three decades, memory safety issues in system programming languages such as C or C++ have been one of the significant sources of security vulnerabilities. However, there exist only a few attempts with limited success to cope with the complexity of C++ program verification. Here we describe and evaluate a novel verification approach based on bounded model checking (BMC) and satisfiability modulo theories (SMT) to verify C++ programs formally. Our verification approach analyzes bounded C++ programs by encoding into SMT various sophisticated features that the C++ programming language …
This paper describes a static verification framework for the message-passing fragment of the Go programming language. Our framework extracts models that over-approximate the message-passing behaviour of a program. These models, or behavioural types, are encoded in Promela, hence can be efficiently verified with Spin. We improve on previous works by verifying programs that include communication-related parameters that are unknown at compile-time, i.e., programs that spawn a parameterised number of threads or that create channels with a parameterised capacity. These programs are checked via a bo…
We explore an approach to verification of programs via program transformation applied to an interpreter of a programming language. A specialization technique known as Turchin's supercompilation is used to specialize some interpreters with respect to the program models. We show that several safety properties of functional programs modeling a class of cache coherence protocols can be proved by a supercompiler and compare the results with our earlier work on direct verification via supercompilation not using intermediate interpretation. Our approach was in part inspired by an earlier work by E. D…
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 …
Trigger-action programming (TAP) is a popular end-user programming framework that can simplify the Internet of Things (IoT) automation with simple trigger-action rules. However, it also introduces new security and safety threats. A lot of advanced techniques have been proposed to address this problem. Rigorously reasoning about the security of a TAP-based IoT system requires a well-defined model and verification method both against rule semantics and physical-world features, e.g., concurrency, rule latency, extended action, tardy attributes, and connection-based rule interactions, which has be…
Formal specification is widely employed in the construction of high-quality software. However, there is often a huge gap between formal specification and actual implementation. While there is already a vast body of work on software testing and verification, the task to ensure that an implementation indeed meets its specification is still undeniably of great difficulty. ATS is a programming language equipped with a highly expressive type system that allows the programmer to specify and implement and then verify within the language itself that an implementation meets its specification. In this p…
