sábado, julio 16, 2005

Bernd Fisher: Generación de código certificable

En el contexto de la 4ta conferencia de Ingeniería de Componentes y Programación Generativa, (Generative Programming and Component Engineering [GPCE'05]), varios temas de mucho interés, y entre ellos, el propuesto por Bernd Fisher: Generación de código certificable. Así se presenta el tema en la informaión previa:

ABSTRACT Code generators based on template expansion techniques are easier to build than purely deductive systems but do not guarantee the same level of assurance: instead of providing correctness-by-construction, the correctness of the generated code depends on the correctness of the generator itself. We present an alternative assurance approach, in which the generator is extended to enable Hoare-style safety proofs for each individual generated program. The proofs ensure that the generated code does not go wrong, i.e., does not violate certain conditions during its execution.

The crucial step in this approach is to extend the generator in such way that it produces all required annotations (i.e., pre-/postconditions and loop invariants) without compromising the assurance provided by the subsequent verification phase. This is achieved by embedding annotation templates into the code templates, which are then instantiated in parallel by the generator. This is feasible because the structure of the generated code and the possible safety properties are known when the generator is developed. It does not compromise the provided assurance because the annotations only serve as auxiliary lemmas and errors in the annotation templates ultimately lead to unprovable safety obligations.

We have implemented this approach and integrated it into the AutoBayes and AutoFilter program generators. We have then used it to fully automatically prove that code generated by the two systems satisfies both language-specific properties such as array-bounds safety or proper variable initialization-before-use and domain-specific properties such as vector normalization, matrix symmetry, or correct sensor input usage.

Otros trabajos: Patrones en la reingeniería de código OO, por Oscar Nierstrasz

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