Is there a tool which can generate a small and simple source tree after config?

[jiangtao.jit]

Hi:

While reading the kernel code
1. the huge amount of files make me scared
    there are too many alike functions in different files
    sometimes I can't figure out which one was really compiled
2. too many macros in the definition of a struct or functions declaration
    confused me a lot
    I tried to follow the generated file autoconf.h to guess the final face
    but it's really a difficult thing

Is there a tool which can generate a small and simple source tree after config?
not pre-processor
just generate a small source tree contains the files and dirs which really will be compiled
and no macros like CONFIG_SMP etc.
according to the configuration

or some other way to understand the architecture of the final working source tree?

Thanks.

--
2011-10-23 
jiangtao.jit