Google has implemented a series of patches which allows us to catch many STL mis-use bugs cheaply and in ABI-compatible way:
http://gcc.gnu.org/ml/gcc-patches/2013-01/msg01074.html and more ...
(just look for __google_stl in google/integration branch).
Some of the bugs we catch this way are not visible to "standard" tools like Valgrind and AddressSanitizer.
These bugs (and more) *are* visible to _GLIBCXX_DEBUG mode, but we've not been able to use that mode due to source incompatibilities, and it has ABI implications as well.
Please consider adding a light-weight ABI-compatible debug mode to trunk, once it re-opens for stage 1.
As of r227595 trunk now supports a _GLIBCXX_ASSERTIONS macro that enables lightweight checks. We will start merging some of the __google_stl checks to trunk and enabling them with that macro (which might give you a number of merge conflicts on your branch, sorry!)