arXiv subjects

Felipe R. Monteiro

Publications and source records attributed to Felipe R. Monteiro.

8 recordsLinked to original sources

arXiv2026

Learning Context-Free Grammars for Grammar-Constrained Decoding via Declarative Agentic Programming with Guarantees

Language models (LMs) are increasingly used to interact with external services via programs written in domain-specific languages (DSLs). Unfortunately, since DSLs are often low-resource and esoteric, LMs frequently produce syntactically invalid programs in these languages. Grammar-constrained decoding can eliminate such failures, but requires syntactic constraints. These are usually in the form of a context-free grammar for the target language, an artifact that is hard to come by for third-party DSLs. In this work, we define an agent, called Autogrammar, that automatically learns context-free grammars from documentation and execution data. Autogrammar is formalized as a Kripke structure whose nondeterministic choices are resolved by a language model, enabling declarative control of agent behavior via linear temporal logic constraints. We evaluate four versions of Autogrammar on three DSLs (i.e., Amazon CloudWatch Logs Insights, Dynatrace Query Language, and Datadog Search Syntax) and find that it generates grammars that achieve near perfect precision on unseen data; that temporal restrictions reduce execution time by 3.8x without incurring statistically-significant loss in precision; that execution data is crucial while documentation is dispensable; and that grammar-constrained decoding using Autogrammar-generated grammars significantly improves end-to-end LM performance on eight out of ten real tasks, matching or exceeding the performance of a professionally-maintained grammar. In comparison, the context-free grammars generated by existing LM baselines and a state-of-the-art formal technique perform significantly worse over the same evaluation.

cs.PL↗

arXiv2026

Kani: A Model Checker for Rust

Rust's ownership type system prevents memory errors in safe code, but certain desirable properties remain orthogonal to compilation: the soundness of unsafe operations (e.g., raw pointer dereferences), functional correctness, and absence of runtime panics. We present Kani, an open-source model checker for Rust that pushes bounded model checking beyond bug-finding to provide correctness guarantees for these properties. Kani compiles proof harnesses from Rust's Mid-level Intermediate Representation (MIR) into CBMC's bit-precise verification engine, automatically checking a comprehensive set of safety properties with no user annotation. To extend verification from bounded to unbounded, Kani provides a specification language comprising function contracts, loop contracts, quantifiers, and function stubbing. We demonstrate feasibility through case studies on industrial Rust projects, where contracts upgraded verification from panic-freedom to functional correctness, uncovering six previously unknown bugs. Kani operates at scale in production CI, with over 16,000 harnesses verified per code change in the Rust standard library verification campaign.

cs.SE↗

arXiv2026

Verifying the Rust Standard Library

Rust's type system prevents many classes of memory errors, yet its standard library relies heavily on unsafe code whose correctness is validated through testing, including dynamic checks under Miri, but lacks static verification. We present what is, to the best of our knowledge, the largest verification campaign reported for a software library: an open, crowdsourced effort that integrates complementary verification tools into the continuous integration of a verification repository forked from the Rust standard library. We analyze the campaign's effectiveness, discuss the practical value of machine-checked proofs for a subset of undefined behaviors (e.g., out-of-bounds access, null and dangling pointer dereferences, and use of uninitialized memory), and frame the remaining obstacles as open challenges for the formal-methods community.

cs.LO↗

arXiv2021

Model Checking C++ Programs

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 offers, such as templates, inheritance, polymorphism, exception handling, and the Standard C++ Libraries. We formalize these features within our formal verification framework using a decidable fragment of first-order logic and then show how state-of-the-art SMT solvers can efficiently handle that. We implemented our verification approach on top of ESBMC. We compare ESBMC to LLBMC and DIVINE, which are state-of-the-art verifiers to check C++ programs directly from the LLVM bitcode. Experimental results show that ESBMC can handle a wide range of C++ programs, presenting a higher number of correct verification results. At the same time, it reduces the verification time if compared to LLBMC and DIVINE tools. Additionally, ESBMC has been applied to a commercial C++ application in the telecommunication domain and successfully detected arithmetic overflow errors, potentially leading to security vulnerabilities.

cs.SE↗

arXiv2019

Boost the Impact of Continuous Formal Verification in Industry

Software model checking has experienced significant progress in the last two decades, however, one of its major bottlenecks for practical applications remains its scalability and adaptability. Here, we describe an approach to integrate software model checking techniques into the DevOps culture by exploiting practices such as continuous integration and regression tests. In particular, our proposed approach looks at the modifications to the software system since its last verification, and submits them to a continuous formal verification process, guided by a set of regression test cases. Our vision is to focus on the developer in order to integrate formal verification techniques into the developer workflow by using their main software development methodologies and tools.

cs.SE↗

arXiv2019

Beyond k-induction: Learning from Counterexamples to Bidirectionally Explore the State Space

We describe and evaluate a novel k-induction proof rule called bidirectional k-induction (bkind), which substantially improves the k-induction bug-finding capabilities. Particularly, bkind exploits the counterexamples generated by the over-approximation step to derive new properties and feed them back to the bounded model checking procedure. We also combine an interval invariant generator and bkind to significantly improve the number of correct verification results. Experimental results show that bkind can considerably reduce the verification time compared to the naive k-induction proof rule, since it only requires half the number of steps to find a given safety property violation in an unsafe program. The bkind algorithm outperforms 2LS, another state-of-the-art k-induction verifier, and produces more than twice correct proofs and about 35% more correct alarms than when analysing a large set of public available benchmarks.

cs.LO↗

arXiv2016

Bounded Model Checking of State-Space Digital Systems: The Impact of Finite Word-Length Effects on the Implementation of Fixed-Point Digital Controllers Based on State-Space Modeling

The extensive use of digital controllers demands a growing effort to prevent design errors that appear due to finite-word length (FWL) effects. However, there is still a gap, regarding verification tools and methodologies to check implementation aspects of control systems. Thus, the present paper describes an approach, which employs bounded model checking (BMC) techniques, to verify fixed-point digital controllers represented by state-space equations. The experimental results demonstrate the sensitivity of such systems to FWL effects and the effectiveness of the proposed approach to detect them. To the best of my knowledge, this is the first contribution tackling formal verification through BMC of fixed-point state-space digital controllers.

cs.SE↗

arXiv2016

Complementary Training Programme for Electrical and Computer Engineering Students Through an Industrial-Academic Collaboration (Extended Version)

We describe the results of an industrial-academic collaboration among the Graduate Program in Electrical Engineering (PPGEE), the Electronics and Information Research Centre (CETELI), and Samsung Eletrônica da Amazônia Ltda. (Samsung), which aims at training human resources for Samsung's research and development (R&D) areas. Inspired by co-operative education systems, this collaboration offers an academic experience by means of a complementary training programme (CTP), in order to train undergraduates and graduate students in electrical and computer engineering, with especial emphasis on digital television (TV), industrial automation, and mobile devices technologies. In particular, this cooperation has provided scholarships for students and financial support for professors and coordinators in addition to the construction of a new building with new laboratories, classrooms, and staff rooms, to assist all research and development activities. Additionally, the cooperation outcomes led to applications developed for Samsung's mobile devices, digital TV, and production processes, an increase of 37% in CETELI's scientific production (i.e., conference and journal papers) as well as professional training for undergraduates and graduate students.

cs.CY↗