Dynamic Verification of C++ Generic Algorithms

Dynamic veriication is a new approach to formal veriication, applicable to generic algorithms such as those found in the Standard Template Library (STL, part of the Draft ANSI/ISO C++ Standard Library). Using behavioral abstraction and symbolic execution techniques, veriications are carried out at a meta-level such that the results can be used in a variety of instances of the generic algorithms without repeating the proofs. This is achieved by substituting for type parameters of generic algorithms special data types that model generic concepts by accepting symbolic inputs and deducing outputs using inference methods. By itself, this symbolic execution technique supports testing of programs with symbolic values at a meta-level. For formal verii-cation we also need to generate multiple program execution paths and use assertions (to handle while loops, for example), but we show how this can be achieved via directives to a conventional debugger program and an analysis database. The assertions must still be supplied, but they can be packaged separately and evaluated as needed by appropriate transfers of control orchestrated via the debugger. Unlike all previous veriication methods, the dynamic veriication method thus works without having to transform source code or process it with special interpreters. We include an example of the formal veriication of an STL generic algorithm.