Data flow analysis for C++ program

I need to do some data flow analysis for C++ programs. Any open source tools that an开发者_开发知识库yone can suggest?

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try to evaluate if gcc and the intermediate front-end code transformation into GIMPLE or GENERIC (intermediate languages for workflow analysis for the code optimizer) fit for your purpose. This is fully free and open source. I just cannot tell you how exactly to output this tree representation but there are many gcc manuals online.

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Running the program and then stepping through and copying data / code flow into a separate running flowchart program works for me. Pencil and paper is good too but not so easy to manipulate or store afterwards.

Even if there is a tool to do this, I believe you are more likely to have a better understanding of the program with my approach.