Lîm Tsú-thuàn

https://discourse.llvm.org/t/llvm-15-0-0-release/65099 Here we go

Update: 15.0.3 https://github.com/llvm/llvm-project/releases/tag/llvmorg-15.0.3

@mewmew Would you like to create the issue in llir/irutil?

Maybe we will also need llvm built-in variables/functions? C-API is a bit dangerous, they are added by linker, not always will be there.

I'm pretty sure **A map of name to function** would be the best, we simply modify `Module` to do so.

@mewmew Probably we can merge these **howto** to document?

I start to analyze this issue, in my view, there have two problems have to solve: 1. which structures should be replaced with interfaces I think this is quite hard...

When I implementing `getelementptr` I found using `Elemer` would be a huge change. I haven't dig into how gep work in codebase but can see there would be a big...

1. `extractvalue ` and `insertvalue `: `aggregateElemType` in `ir` and `ir/constant` has different behavior. One allows `PointerType` and one not, if this is not expected then we could use one...

I have another idea: What if we make every IR structure became an interface. Therefore `Function` for example, would be: ```go type Function interface { // ... } var _...