LLD's software architecture

Hi,

I'm analysing the LLD code structure (aka architecture) and am
trying to mold it into a component model.
Currently I see 4 components:
- Driver
- ReaderWriter
- Passes
- Core

I wonder if this is the order that they're supposed to be in,
since there are also code dependencies upwards from:
Core -> ReaderWriter
Passes -> ReaderWriter
ReaderWriter -> Driver

For a graphical view check:
http://c2lang.org/docs/lld_architecture_96e1b5e02.png

I think that with a few surgical patches, the dependency tree
can be completely free of circular deps.

Bas