Deeply Integrating C11 Code Support into Isabelle/PIDE

Abstract

We present a framework for C code in C11 syntax deeply integrated into the Isabelle/PIDE development environment. Our framework provides an abstract interface for verification back-ends to be plugged-in independently. Thus, various techniques such as deductive program verification or whitebox testing can be applied to the same source, which is part of an integrated PIDE document model. Semantic back-ends are free to choose the supported C fragment and its semantics. In particular, they can differ on the chosen memory model or the specification mechanism for framing conditions.Our framework supports semantic annotations of C sources in the form of comments. Annotations serve to locally control back-end settings, and can express the term focus to which an annotation refers. Both the logical and the syntactic context are available when semantic annotations are evaluated. As a consequence, a formula in an annotation can refer both to HOL or C variables.Our approach demonstrates the degree of maturity and expressive power the Isabelle/PIDE subsystem has achieved in recent years. Our integration technique employs Lex and Yacc style grammars to ensure efficient deterministic parsing. We present two case studies for the integration of (known) semantic back-ends in order to validate the design decisions for our back-end interface.

Unifying semantic foundations for automated verification tools in Isabelle/UTP

“…We show how lenses allow us to perform symbolic evaluation, reason about aliasing of different variables, and model frames and Morgan's specification statement [61]. Though we use UTP notation throughout, different syntactic flavours can easily be accommodated using Isabelle's powerful syntax processing facilities [77].…”

Access: Assurance Case Centric Engineering of Safety-Critical Systems

“…Development centres around documents called Isabelle theories, which encode graphs of hyperlinked mathematical artifacts, such as definitions, theorems, and proofs. Formal method integration is supported by (1) a flexible front-end, which supports a variety of languages (Tuong and Wolff, 2019) and their translation into formal semantics; (2) an extensible plugin-oriented architecture where external tools, such as SMT solvers (Blanchette et al, 2011), can improve automation; and (3) incremental theory processing (Wenzel and Wolff, 2007). Moreover, Isabelle can be installed as a server component which other tools can make use of as a verification tool service.…”

Certifying Differential Equation Solutions from Computer Algebra Systems in Isabelle/HOL

“…KeYmaera X is, however, restricted to reasoning about dL hybrid programs, and cannot be applied directly to other notations. In particular, we cannot show that a controller specification is refined by a given implementation in a language like C [16], although tools such as VeriPhy [17] and ModelPlex [18] somewhat bridge this gap. It also cannot handle transcendental functions, such as sin and log, which are often used by control engineers.…”

“…dL has also been implemented [19,20,21] in the Isabelle proof assistant [4], as both a deep [19] and shallow embedding [20,21]. Verification in Isabelle brings the advantage of generality, whereby the hybrid systems proof could be used to show correctness of an implementation [16], or used in a larger proof about a complex system. It also allows integration with several notations in a single development, which is the goal of our target verification framework, Isabelle/UTP [22].…”