Villoc is a heap visualisation tool, it's a python script that renders a static html file. An example can be seen here: http://wapiflapi.github.io/villoc/, this is villoc running on an exploit of PlaidCTF 2015's challenge PlaidDB.
The easiest way to use villoc is probably to run the following command and open out.html in a browser.
ltrace ./target |& villoc.py - out.html;
It is probably a good idea to disable ASLR for repeatable results and to use a file to pass the ltrace to villoc because otherwise the target's error output will be interleaved and might confuse villoc sometimes.
setarch x86_64 -R ltrace -o trace ./target; villoc.py trace out.html;
This has been made with glibc's dl_malloc in mind. But it should work for other
implementations, especially if you play with the
options to indicate how much overhead the targeted malloc adds to the user data.