Source Navigator NG is a source code analysis tool. With it, you can edit your source code, display relationships between classes and functions and members, and display call trees. You can navigate your source code and easily get to declarations or implementations of functions, variables and macros (commonly called "symbols") which helps you discovering and mapping unknown source code for enhancement or maintenance tasks.
Code Insight is a Open source, cross platform software for developers to browse, edit and understand code easily, like commercial one named Source Insight. Based on CodeLite IDE the CodeInsight also is aligned with GPL license.