How to get AST for C source in plugin?

[Ilya Caramishev]

Hi,

I've posted this question to gcc-help list back in December and haven't 
got any reaction, so I decided to repost it here.

I'm trying to do some static analysis of C source using GCC 4.5 and my 
plugin.

I've tried registering my plugin for PLUGIN_FINISH_UNIT event. My plugin 
gets called, but I couldn't find a way to access AST - nothing is passed 
to my plugin as parameter. Maybe there is some GCC's global variable 
that contains AST I can use?

Alternatively I've tried Kenji Koyanagi's patch 
(http://gcc.gnu.org/ml/gcc/2009-03/msg00136.html) and it worked just 
fine, but I don't know whether this patch is going to be accepted in GCC 
4.5 codeline, which can be a show-stopper for me, because I want my 
plugin to work with standard compiler. Are there plans to add 
PLUGIN_C_PRE_GENERICIZE event to GCC plugin infrastructure?

Are there any other ways to get AST for the whole translation unit or 
separate functions in my plugin?

Regards,
Ilya