Dear Sir/Madam, My name is Sean Hsiao, a master student of Computer Science of Oklahoma State University. My adviser, Dr. Istvan Jonyer, and I are doing a project. We need to know some information about Abstract Syntax Tree. So, I need to modify the original code of GCC to obtain the AST. However, there are too many files, would you please tell me which file of GCC generates AST? Thank you very much!! Sincerely, Sean Hsiao