I am planning to build a simple open source code visualization tool to generate UML sequence diagrams because the cost of VS Ultimate is IMHO ridiculous and impractical, but I find their sequence diagram generating tool to be extremely useful when trying to familiarize yourself with pre-existing code. I have found that existing commercial and open source alternatives are confusing and do not work beyond simple scenarios. Perhaps most importantly I see this as an opportunity to understand more about something I use on a daily basis.
From my preliminary research, it seems Mono.Cecil is worth considering per this SO question: Look if a method is called inside a method using reflection, but this currently does not support anything past .NET 4.0. I've been considering Roslyn, but I'm curious how significant of an advantage one may get by parsing the IL directly as with Mono.Cecil. Are there other options?
Any advice here would be much appreciated!