A recent paper by Franco Gasperoni describing how a Free Software toolset (Coverage) and virtualization technology (QEMU) can be used effectively to assure code coverage in the development of software applications. While an important target use of the coverage toolset is safety-critical embedded applications, the design of the tools allows its use in non safety-critical projects.
http://www.adacore.com/uploads/technical-papers/coverage_and_free_software.pdf