LLVM has a decent amount of documentation on integrating garbage collection, not on how to write one though.<p>Some more advanced GC integration functionality was added more recently because of the work on Webkit&#x27;s FTL JIT: <a href="http:&#x2F;&#x2F;llvm.org&#x2F;docs&#x2F;Statepoints.html" rel="nofollow">http:&#x2F;&#x2F;llvm.org&#x2F;docs&#x2F;Statepoints.html</a>