A mechanized semantics for C++ object construction and destruction, with applications to resource management

International audienceWe present a formal operational semantics and its Coq mechanization for the C++ object model, featuring object construction and destruction, shared and repeated multiple inheritance, and virtual function call dispatch. These are key C++ language features for high-level system programming, in particular for predictable and reliable resource management. This paper is the first to present a formal mechanized account of the metatheory of construction and destruction in C++, and applications to popular programming techniques such as "resource acquisition is initialization." We also report on irregularities and apparent contradictions in the ISO C++03 and C++11 standards

Parsing C/C++ Code without Preprocessing

It is difficult to develop style-preserving source-to-source transformation engines for C and C++. The main reason is not the complexity of those languages, but the use of the C pre-processor (cpp), especially ifdefs and macros. This has for example hindered the development of refactoring tools for C and C++. In this paper we propose to combine multiple techniques and heuristics to parse C/C++ source files as-is, while still having only a few modifications to the original grammars of C and C++. We rely on the fact that in most C and C++ software, programmers follow a limited number of conventions on the use of cpp which makes it possible to disambiguate different situations by just looking at the context, names, or indentation of cpp constructs. We have implemented a parser, Yacfe, based on these techniques and evaluated it on 16 large open source projects. Yacfe can on average parse 96% of those projects correctly. As a side effect we also found mistakes in code that was not compiled because it was protected by particular ifdefs, but that was still analyzed by Yacfe. Using Yacfe on new projects may require adapting some of our techniques. We found that as conventions and idioms are shared by many projects, the adaptation time is on average less than 2 hours for a new project