LLVM帶了了ARC,神一樣的東西～夢幻般的思想。
徹底瞭解了GC和引用計數那個好的爭論。
Automatic Reference Counting
Automatic Reference Counting (ARC) for Objective-C makes memory management the job of the compiler. By enabling ARC with the new Apple LLVM compiler, you will never need to type retain or release again, dramatically simplifying the development process, while reducing crashes and memory leaks. The compiler has a complete understanding of your objects, and releases each object the instant it is no longer used, so apps run as fast as ever, with predictable, smooth performance.