FlameGraph : Visualization of hierarchical data, especially pofiled stack traces ( https://www.brendangregg.com/flamegraphs.html https://github.com/brendangregg/FlameGraph )
rtags : A client/server indexer for C/C++/ObjC[++] with integration for Emacs ( http://www.rtags.net/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a flow
For Paludis use this rsync : rsync://gentoo.zugaina.org/flow-portage
If you have a problem : ycarus(-at-)zugaina.org