A program analysis tool can play an important role in helping users understand and improve large application codes. Dragon is a robust interactive program analysis tool based on the Open64 compiler, which is an Open source C/C++/Fortran77/90 compiler for Intel Itanium systems. We designed and developed the Dragon analysis tool to support manual optimization and parallelization of large applications by exploiting the powerful analyses of the Open64 compiler. Dragon enables users to visualize and print the essential program structure of and obtains information on their large applications. Current features include the call graph, flow graph, and data dependences. Ongoing work extends both Open64 and Dragon by a new call graph construction algorithm and its related interprocedural analysis, global variable definition and usage analysis, and an external interface that can be used by other tools such as profilers and debuggers to share program analysis information. Future work includes supporting the creation and optimization of shared memory parallel programs written using OpenMP.