Mikael Persson on the clang mailing list picked this up some time back and updated it.
http://article.gmane.org/gmane.comp.compilers.clang.devel/35...
He cleaned it up and extended to work with callgrind. Looking at this data in kcachegrind is beautiful thing.
https://github.com/mikael-s-persson/templight https://github.com/mikael-s-persson/templight-tools