LLVM 3.2 to latest

[ramonasuncion]

This is what I've been doing so far. However, I'm making an issue to keep track of all the changes since this is going to take a while. I've been slowly moving things over using the llvm-project to find how they've upgraded the project overtime. But I should have incrementally upgraded the version or at least get it to run on it's currently version before going all in. The only thing saving me is Clion right now.

[ramonasuncion]

I really fucked up with this one. I've been reading the docs and I have a lot to do...

• I have to swtich from the legacy pass manager to the modern one (PassBuilder)
• The PointerType doesn't carry element type information anymore because of opaque pointers
• The vector sizing logic is now split so there isn't any VectorType::getNumElements anymore
• There is a bunch of raw pointers being used throughout the code. I want to replace them with unique_ptr

And just a bunch of others thing...