Libcc1 is the GCC cc1 plugin for the GDB debugger. With the latest GCC SVN/Git code tonight is now C++ support to complement the C interfaces.
With this code thanks to Red Hat is the C++ libcc1 support. "Extend libcc1's C API to distinguish between integral types with the same width, as in C++. Likewise for float types. Export small bits of functionality from the C++ front-end for use in libcc1. Add support for the C++ front-end to look up names and addresses using a libcc1-registered binding oracle. Add support for global friends."
Red Hat developer Alexandre Oliva who spearheaded this code had written this blog post a few months back about the impact of libcc1 C++ support for those using GDB. Check out that post for all the interesting technical details.
GCC 7.1 is expected to be officially released in March~April.