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163
Model Checking Programs
, 2003
"... The majority of work carried out in the formal methods community throughout the last three decades has (for good reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers, proof checkers and model checkers. In this pape ..."
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Cited by 592 (63 self)
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The majority of work carried out in the formal methods community throughout the last three decades has (for good reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers, proof checkers and model checkers. In this paper we will attempt to give convincing arguments for why we believe it is time for the formal methods community to shift some of its attention towards the analysis of programs written in modern programming languages. In keeping with this philosophy we have developed a verification and testing environment for Java, called Java PathFinder (JPF), which integrates model checking, program analysis and testing. Part of this work has consisted of building a new Java Virtual Machine that interprets Java bytecode. JPF uses state compression to handle big states, and partial order and symmetry reduction, slicing, abstraction, and runtime analysis techniques to reduce the state space. JPF has been applied to a realtime avionics operating system developed at Honeywell, illustrating an intricate error, and to a model of a spacecraft controller, illustrating the combination of abstraction, runtime analysis, and slicing with model checking.
Simplify: A theorem prover for program checking
 J. ACM
, 2003
"... This paper provides a detailed description of the automatic theorem prover Simplify, which is the proof engine of the Extended Static Checkers ESC/Java and ESC/Modula3. Simplify uses the NelsonOppen method to combine decision procedures for several important theories, and also employs a matcher to ..."
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Cited by 431 (2 self)
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This paper provides a detailed description of the automatic theorem prover Simplify, which is the proof engine of the Extended Static Checkers ESC/Java and ESC/Modula3. Simplify uses the NelsonOppen method to combine decision procedures for several important theories, and also employs a matcher to reason about quantifiers. Instead of conventional matching in a term DAG, Simplify matches up to equivalence in an Egraph, which detects many relevant pattern instances that would be missed by the conventional approach. The paper describes two techniques, labels and counterexample contexts, for helping the user to determine the reason that a false conjecture is false. The paper includes detailed performance figures on conjectures derived from realistic programchecking problems.
A Fast LinearArithmetic Solver for DPLL(T)
, 2006
"... We present a new Simplexbased linear arithmetic solver that can be integrated efficiently in the DPLL(T) framework. The new solver improves over existing approaches by enabling fast backtracking, supporting a priori simplification to reduce the problem size, and providing an efficient form of the ..."
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Cited by 289 (13 self)
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We present a new Simplexbased linear arithmetic solver that can be integrated efficiently in the DPLL(T) framework. The new solver improves over existing approaches by enabling fast backtracking, supporting a priori simplification to reduce the problem size, and providing an efficient form of theory propagation. We also present a new and simple approach for solving strict inequalities. Experimental results show substantial performance improvements over existing tools that use other Simplexbased solvers in DPLL(T) decision procedures. The new solver is even competitive with stateoftheart tools specialized for the difference logic fragment.
A decision procedure for bitvectors and arrays
 IN COMPUTER AIDED VERIFICATION, NUMBER 4590 IN LNCS
, 2007
"... STP is a decision procedure for the satisfiability of quantifierfree formulas in the theory of bitvectors and arrays that has been optimized for large problems encountered in software analysis applications. The basic architecture of the procedure consists of wordlevel preprocessing algorithms fo ..."
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Cited by 190 (11 self)
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STP is a decision procedure for the satisfiability of quantifierfree formulas in the theory of bitvectors and arrays that has been optimized for large problems encountered in software analysis applications. The basic architecture of the procedure consists of wordlevel preprocessing algorithms followed by translation to SAT. The primary bottlenecks in software verification and bug finding applications are large arrays and linear bitvector arithmetic. New algorithms based on the abstractionrefinement paradigm are presented for reasoning about large arrays. A solver for bitvector linear arithmetic is presented that eliminates variables and parts of variables to enable other transformations, and reduce the size of the problem that is eventually received by the SAT solver. These and other algorithms have been implemented in STP, which has been heavily tested over thousands of examples obtained from several realworld applications. Experimental results indicate that the above mix of algorithms along with the overall architecture is far more effective, for a variety of applications, than a direct translation of the original formula to SAT or other comparable decision procedures.
Modeling and Verifying Systems using a Logic of Counter Arithmetic with Lambda Expressions and Uninterpreted Functions
, 2002
"... In this paper, we present the logic of Counter arithmetic with Lambda expressions and Uninterpreted functions (CLU). CLU generalizes the logic of equality with uninterpreted functions (EUF) with constrained lambda expressions, ordering, and successor and predecessor functions. In addition to mod ..."
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Cited by 154 (42 self)
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In this paper, we present the logic of Counter arithmetic with Lambda expressions and Uninterpreted functions (CLU). CLU generalizes the logic of equality with uninterpreted functions (EUF) with constrained lambda expressions, ordering, and successor and predecessor functions. In addition to modeling pipelined processors that EUF has proved useful for, CLU can be used to model many infinitestate systems including those with infinite memories, finite and infinite queues including lossy channels, and networks of identical processes. Even with this richer expressive power, the validity of a CLU formula can be efficiently decided by translating it to a propositional formula, and then using Boolean methods to check validity. We give theoretical and empirical evidence for the efficiency of our decision procedure. We also describe verification techniques that we have used on a variety of systems, including an outoforder execution unit and the loadstore unit of an industrial microprocessor.
Experience with Predicate Abstraction
 IN COMPUTER AIDED VERIFICATION
, 1999
"... This reports some experiences with a recentlyimplemented prototype system for verification using predicate abstraction, based on the method of Graf and Saidi [9]. Systems are described using a language of iterated guarded commands, called MurOE \Gamma\Gamma (since it is a simplified version o ..."
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Cited by 143 (6 self)
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This reports some experiences with a recentlyimplemented prototype system for verification using predicate abstraction, based on the method of Graf and Saidi [9]. Systems are described using a language of iterated guarded commands, called MurOE \Gamma\Gamma (since it is a simplified version of our MurOE protocol description language). The system makes use of two libraries: SVC [1] (an efficient decision procedure for quantifierfree firstorder logic) and the CMU BDD library. The use of these libraries increases the scope of problems that can be handled by predicate abstraction through increased efficiency, especially in SVC, which is typically called thousands of times. The verification system also provides limited support for quantifiers in formulas. The system ...
DPLL(T): Fast Decision Procedures
, 2004
"... The logic of equality with uninterpreted functions (EUF) and its extensions have been widely applied to processor verification, by means of a large variety of progressively more sophisticated (lazy or eager) translations into propositional SAT. Here we propose a new approach, namely a general DP ..."
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Cited by 141 (14 self)
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The logic of equality with uninterpreted functions (EUF) and its extensions have been widely applied to processor verification, by means of a large variety of progressively more sophisticated (lazy or eager) translations into propositional SAT. Here we propose a new approach, namely a general DPLL(X) engine, whose parameter X can be instantiated with a specialized solver Solver T for a given theory T , thus producing a system DPLL(T ). We describe this DPLL(T ) scheme, the interface between DPLL(X) and Solver T , the architecture of DPLL(X), and our solver for EUF, which includes incremental and backtrackable congruence closure algorithms for dealing with the builtin equality and the integer successor and predecessor symbols. Experiments with a first implementation indicate that our technique already outperforms the previous methods on most benchmarks, and scales up very well.
CVC: a Cooperating Validity Checker
 In 14th International Conference on ComputerAided Verification
, 2002
"... Decision procedures for decidable logics and logical theories have proven to be useful tools in verification. This paper describes the CVC ("Cooperating Validity Checker") decision procedure. CVC implements a framework for combining subsidiary decision procedures for certain logical theori ..."
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Cited by 122 (22 self)
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Decision procedures for decidable logics and logical theories have proven to be useful tools in verification. This paper describes the CVC ("Cooperating Validity Checker") decision procedure. CVC implements a framework for combining subsidiary decision procedures for certain logical theories into a decision procedure for the theories' union. Subsidiary decision procedures for theories of arrays, inductive datatypes, and linear real arithmetic are currently implemented. Other notable features of CVC are the incorporation of the highperformance Cha solver for propositional reasoning, and the ability to produce independently checkable proofs for valid formulas.
Formal verification in hardware design: A survey
, 1997
"... In recent years, formal methods have emerged as an alternative approach to ensuring the quality and correctness of hardware designs, overcoming some of the limitations of traditional validation techniques such as simulation and testing. There are two main aspects to the application of formal methods ..."
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Cited by 113 (0 self)
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In recent years, formal methods have emerged as an alternative approach to ensuring the quality and correctness of hardware designs, overcoming some of the limitations of traditional validation techniques such as simulation and testing. There are two main aspects to the application of formal methods in a design process: The formal framework used to specify desired properties of a design, and the verification techniques and tools used to reason about the relationship between a specification and a corresponding implementation. We survey a variety of frameworks and techniques which have been proposed in the literature and applied to actual designs. The specification frameworks we describe include temporal logics, predicate logic, abstraction and refinement, as well as containment between!regular languages. The verification techniques presented include model checking, automatatheoretic techniques, automated theorem proving, and approaches that integrate the above methods.
Java PathFinder  Second Generation of a Java Model Checker
 In Proceedings of the Workshop on Advances in Verification
, 2000
"... ion We have been developing an automated abstraction tool, which converts a Java program to an abstract program with respect to userspecified abstraction criteria. The user can specify abstractions by removing variables in the concrete program and/or adding new variables (currently the tool suppor ..."
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Cited by 113 (2 self)
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ion We have been developing an automated abstraction tool, which converts a Java program to an abstract program with respect to userspecified abstraction criteria. The user can specify abstractions by removing variables in the concrete program and/or adding new variables (currently the tool supports adding boolean types only) to the abstract program. Specifically, the user selects variables that must be removed and adds abstract variables that represent the predicates in which these variables occurred (typically the predicates are selected from conditions in if and while statements). Given a Java program and such abstraction criteria, the tool generates an abstract Java program in terms of the new abstract variables and unremoved concrete variables. To compute the conversion automatically, JPF uses a decision procedure, SVC (Stanford Validity Checker), which checks the validity of logical expressions [1]. The abstraction tool is designed for objectoriented programs. The user can sp...