#### Context: CEA List, Software Safety and Security Lab
[CEA List](http://www-list.cea.fr/en/)'s offices are located at the heart of Université Paris-Saclay, the
largest European cluster of public and private research. Within [CEA List](http://www-list.cea.fr/en/), 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. We are a fifty-person team, and your work will
have a direct and visible impact on the state of formal verification.
#### Work Description
Our team develops [Frama-C](https://www.frama-c.com), a code analysis platform for C programs which
provides several analyzers as plug-ins. [Frama-C](https://www.frama-c.com) itself is developed in Ocaml.
[Frama-C](https://www.frama-c.com) allows the user to annotate C programs with formal specifications
written in the [ACSL](https://www.frama-c.com/html/acsl.html) specification language. [Frama-C](https://www.frama-c.com) 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.
[E-ACSL](https://www.frama-c.com/fc-plugins/e-acsl.html) is the [Frama-C](https://www.frama-c.com) plug-in dedicated to runtime assertion checking. It
converts a C program extended with formal annotations written in a subset of [ACSL](https://www.frama-c.com/html/acsl.html)
into a new C program which checks the validity of annotations at runtime: by
default, the program execution stops whenever one annotation is violated, or
behaves in the same way than the
input program if all its annotations are valid. One key feature of [E-ACSL](https://www.frama-c.com/fc-plugins/e-acsl.html) is the
expressivity of its specification language which allows the user to describe
powerful safety and security properties. Another key feature is the efficiency
of the generated code which relies on a custom memory library
and dedicated static analyses.
However [E-ACSL](https://www.frama-c.com/fc-plugins/e-acsl.html) can still be
improved in many ways in order to extend its expressivity and to reduce its
memory and time overheads. To reach this goal, (s)he shall make several
contributions, for example regarding some of the following objectives:
- improve the current compilation scheme to reduce the memory footprint of the
generated code;
- design new compilation techniques and/or adapt existing ones in order to
optimize the efficiency of the generated code;
- design novel dedicated fast static analyses to minimize the generated code;
- design one or several new intermediate representations that would make
these developments easier;
- evaluate the benefits of these improvements on concrete benchmarks and/or
use cases.
#### Qualifications
Knowledge in at least one of the following fields is required:
#### Context: CEA List, Software Safety and Security Lab
[CEA List](http://www-list.cea.fr/en/)'s offices are located at the heart of Université Paris-Saclay, the
largest European cluster of public and private research. Within [CEA List](http://www-list.cea.fr/en/), 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. We are a fifty-person team, and your work will
have a direct and visible impact on the state of formal verification.
#### Work Description
Our team develops [Frama-C](https://www.frama-c.com), a code analysis platform for C programs which
provides several analyzers as plug-ins. [Frama-C](https://www.frama-c.com) itself is developed in Ocaml.
[Frama-C](https://www.frama-c.com) allows the user to annotate C programs with formal specifications
written in the [ACSL](https://www.frama-c.com/html/acsl.html) specification language. [Frama-C](https://www.frama-c.com) 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.
[E-ACSL](https://www.frama-c.com/fc-plugins/e-acsl.html) is the [Frama-C](https://www.frama-c.com) plug-in dedicated to runtime assertion
checking. It converts a C program extended with
formal annotations written in a subset of [ACSL](https://www.frama-c.com/html/acsl.html) into a new C program which
checks the validity of annotations at runtime: by default, the program execution
stops whenever one annotation is violated, or behaves in the same way than the
input program if all its annotations are valid. For doing so, [E-ACSL](https://www.frama-c.com/fc-plugins/e-acsl.html) performs an
heavy implementation of the original source code to insert its own code that
monitors the [ACSL](https://www.frama-c.com/html/acsl.html) annotations. This technique is usually referred to as
*(online) inline runtime verification*. However,
depending on the context of application, this heavy instrumentation may lead to
prohibitive memory and runtime overheads, as well as security concerns.
The goal of the PhD consists in designing and implementing an *outline runtime
verification technique*
for [E-ACSL](https://www.frama-c.com/fc-plugins/e-acsl.html), compatible with the existing
inline technique. Outline runtime verification consists in placing the monitor
in an external entity (e.g., another thread, or a remote server) for limiting
the instrumentation to communication activities with the remote
monitor. While this technique is well known and often
applied to monitoring of temporal properties, it was never applied to runtime
assertion checking, which raises several challenges regarding the data that need
to be monitored. The expected contributions are:
- designing a new instrumentation scheme for outline runtime assertion checking;
- designing a new internal representation for the monitor, usable for both
inline and outline runtime assertion checking;
- implementing the new representation and the new instrumentation scheme inside
