Design and develop the new symbolic linker of Frama-C

Context: CEA List, Software Safety and Security Lab

CEA List’s offices are located at the heart of Université Paris-Saclay, the largest European cluster of public and private research. Within CEA List, the Software Safety and Security Lab has an ambitious goal: help designers, developers and validation experts ship high-confidence systems and software.

Systems in our surroundings are getting more and more complex, and we have built a reputation for efficiently using formal reasoning to demonstrate their trustworthiness through the design of methods and tools to ensure that real-world systems can comply with the highest safety and security standards. In doing so, we get to interact with the most creative people in academia and the industry, worldwide.

Our organizational structure is simple: those who pioneer new concepts are the ones who get to implement them. Your work will have a direct and visible impact on the state of formal verification.

Work Description

Our team develops Frama-C, a code analysis platform for C programs which provides several analyzers as plug-ins. Frama-C itself is developed in OCaml. Frama-C allows the user to annotate C programs with formal specifications written in a specification language named ACSL. Frama-C can then ensure that a C program satisfies its formal specification by relying on several techniques including abstract interpretation, weakest preconditions calculus, and runtime assertion checking.

Frama-C has its own (symbolic) link phase. It allows detecting some classes of undefined behaviors related to incoherent symbols declarations across compilation units. Basically, from a set of ASTs (one for each file of the project), it generates a single AST that represents the entire system. Today, we need to change the behavior of this component to make it more efficient to detect undefined behaviors, deal with implementation specific behaviors, provide a better API and prepare for multi-language support.

Your role will be to: - design the new linker and its new API, taking in account the constraints related to separated compilation in mainstream programming languages, and the needs from the different Frama-C analyzers, - implement the new linker in a highly configurable way so that it can be both used with strict acceptance rules or permissive behavior (to capture code that exists in the wild), - adapt the different analyzers to the new API, - extensively test the system on existing benchmarks.

Qualifications

• PhD or more than three years of experience in a research-intensive team
• Ability to develop in OCaml or other functional languages
• Knowledge of formal methods or language semantics
• Knowledge of the C language and ability to quickly grasp new ones

Application

This position will be filled as soon as possible; yet a 3+-months procedure for administrative and security purposes is required.

• Virgile Prevosto
• Allan Blanchard