An associated LWN article has some context:<p><a href="https://lwn.net/Articles/451306/" rel="nofollow">https://lwn.net/Articles/451306/</a><p>The gcc plugin (written in Python) used to generate the plot:<p><a href="http://git.fedorahosted.org/git/?p=gcc-python-plugin.git;a=blob;f=generate-passes-svg.py" rel="nofollow">http://git.fedorahosted.org/git/?p=gcc-python-plugin.git;a=b...</a>