689 research outputs found
Finding Counterexamples from Parsing Conflicts
Abstract Writing a parser remains remarkably painful. Automatic parser generators offer a powerful and systematic way to parse complex grammars, but debugging conflicts in grammars can be time-consuming even for experienced language designers. Better tools for diagnosing parsing conflicts will alleviate this difficulty. This paper proposes a practical algorithm that generates compact, helpful counterexamples for LALR grammars. For each parsing conflict in a grammar, a counterexample demonstrating the conflict is constructed. When the grammar in question is ambiguous, the algorithm usually generates a compact counterexample illustrating the ambiguity. This algorithm has been implemented as an extension to the CUP parser generator. The results from applying this implementation to a diverse collection of faulty grammars show that the algorithm is practical, effective, and suitable for inclusion in other LALR parser generators
Testing SDRT's Right Frontier
The Right Frontier Constraint (RFC), as a constraint on the attachment of new
constituents to an existing discourse structure, has important implications for
the interpretation of anaphoric elements in discourse and for Machine Learning
(ML) approaches to learning discourse structures. In this paper we provide
strong empirical support for SDRT's version of RFC. The analysis of about 100
doubly annotated documents by five different naive annotators shows that SDRT's
RFC is respected about 95% of the time. The qualitative analysis of presumed
violations that we have performed shows that they are either click-errors or
structural misconceptions
Bounded LTL Model Checking with Stable Models
In this paper bounded model checking of asynchronous concurrent systems is
introduced as a promising application area for answer set programming. As the
model of asynchronous systems a generalisation of communicating automata,
1-safe Petri nets, are used. It is shown how a 1-safe Petri net and a
requirement on the behaviour of the net can be translated into a logic program
such that the bounded model checking problem for the net can be solved by
computing stable models of the corresponding program. The use of the stable
model semantics leads to compact encodings of bounded reachability and deadlock
detection tasks as well as the more general problem of bounded model checking
of linear temporal logic. Correctness proofs of the devised translations are
given, and some experimental results using the translation and the Smodels
system are presented.Comment: 32 pages, to appear in Theory and Practice of Logic Programmin
Diagnose network failures via data-plane analysis
Diagnosing problems in networks is a time-consuming and error-prone process. Previous tools to assist operators primarily focus on analyzing control
plane configuration. Configuration analysis is limited in that it cannot find
bugs in router software, and is harder to generalize across protocols since it
must model complex configuration languages and dynamic protocol behavior.
This paper studies an alternate approach: diagnosing problems through
static analysis of the data plane. This approach can catch bugs that are
invisible at the level of configuration files, and simplifies unified analysis of a
network across many protocols and implementations. We present Anteater, a
tool for checking invariants in the data plane. Anteater translates high-level
network invariants into boolean satisfiability problems, checks them against
network state using a SAT solver, and reports counterexamples if violations
have been found. Applied to a large campus network, Anteater revealed 23
bugs, including forwarding loops and stale ACL rules, with only five false
positives. Nine of these faults are being fixed by campus network operators
On Counterexample Guided Quantifier Instantiation for Synthesis in CVC4
We introduce the first program synthesis engine implemented inside an SMT
solver. We present an approach that extracts solution functions from
unsatisfiability proofs of the negated form of synthesis conjectures. We also
discuss novel counterexample-guided techniques for quantifier instantiation
that we use to make finding such proofs practically feasible. A particularly
important class of specifications are single-invocation properties, for which
we present a dedicated algorithm. To support syntax restrictions on generated
solutions, our approach can transform a solution found without restrictions
into the desired syntactic form. As an alternative, we show how to use
evaluation function axioms to embed syntactic restrictions into constraints
over algebraic datatypes, and then use an algebraic datatype decision procedure
to drive synthesis. Our experimental evaluation on syntax-guided synthesis
benchmarks shows that our implementation in the CVC4 SMT solver is competitive
with state-of-the-art tools for synthesis
SmartAnvil: Open-Source Tool Suite for Smart Contract Analysis
International audienceSmart contracts are new computational units with special properties: they act as classes with aspectual concerns; their memory structure is more complex than mere objects; they are obscure in the sense that once deployed it is difficult to access their internal state; they reside in an append-only chain. There is a need to support the building of new generation tools to help developers. Such support should tackle several important aspects: (1) the static structure of the contract, (2) the object nature of published contracts, and (3) the overall data chain composed of blocks and transactions. In this chapter, we present SmartAnvil an open platform to build software analysis tools around smart contracts. We illustrate the general components and we focus on three important aspects: support for static analysis of Solidity smart contracts, deployed smart contract binary analysis through inspection, and blockchain navigation and querying. SmartAnvil is open-source and supports a bridge to the Moose data and software analysis platform
Proceedings of Monterey Workshop 2001 Engineering Automation for Sofware Intensive System Integration
The 2001 Monterey Workshop on Engineering Automation for Software Intensive System Integration was sponsored by the Office of Naval Research, Air Force Office of Scientific Research, Army Research Office and the Defense Advance Research Projects Agency. It is our pleasure to thank the workshop advisory and sponsors for their vision of a principled engineering solution for software and for their many-year tireless effort in supporting a series of workshops to bring everyone together.This workshop is the 8 in a series of International workshops. The workshop was held in Monterey Beach Hotel, Monterey, California during June 18-22, 2001. The general theme of the workshop has been to present and discuss research works that aims at increasing the practical impact of formal methods for software and systems engineering. The particular focus of this workshop was "Engineering Automation for Software Intensive System Integration". Previous workshops have been focused on issues including, "Real-time & Concurrent Systems", "Software Merging and Slicing", "Software Evolution", "Software Architecture", "Requirements Targeting Software" and "Modeling Software System Structures in a fastly moving scenario".Office of Naval ResearchAir Force Office of Scientific Research Army Research OfficeDefense Advanced Research Projects AgencyApproved for public release, distribution unlimite
- …