Intermediate representation

[Nicolas COLLIN]

Hello.
First I apologize for my english but I'm french and sometimes I make 
mistakes.

I have to create a file containing some informations by processing C++ 
code source for work.
But why create a whole lexical analyzer while I can use the intermediate 
representation tree of GCC ?
To do it, I'm going to introduce a fonction in GCC which analyze the 
intermediate representation tree used by GCC and create a file 
containing all of the informations I need.
I read all the informations I found about the tree and now my problem is 
that I don't know how to introduce this very function into GCC (I 
haven't found anything about it over the net).
What is the best way to do it ? Create a new "back-end" ? I read about 
it and I don't think it could work. Can I put it into the source code 
instead ? If so, where can I put it ?
I work on egcs1.1, but I know that the tree is implemented in, so it can 
work.
I'm sorry to bother you with this but I searched a long time over the 
net and didn't find any clue about the way to do it.

Thank you very much.

Nicolas COLLIN