Flowchart from Source Code for a clear view of the code.
Rich Call/Caller/File, Class Trees
Automatic Code/Comment Formatting for improved readability
Export to BMP/JPEG/Visio, Code Browser
Editions:
DataFlow: Object DataFlows, CallFlows, Inline expansion of flowcharts
Docs: Comprehensive HTML docs with Flowcharts/Trees
Professional: Code Publisher, Project Flowcharts, Custom symbols in flowcharts, Batch output Flowcharts/Trees

Crystal REVS is the best context-sensitive editor there is. Has Flowcharts, Call/Caller Trees, Tokens/Comment Panel, Auto-Format, Visio export, State diagrams.
Editions:
Rules: MISRA C Static Checking
DataFlow: Rich Trees, Object DataFlows, CallFlows, Inline expansion of flowcharts
Docs: Flowcharts/Trees in HTML docs
Professional: Publisher, Custom symbols, Batch output Flowcharts/Trees
ProPlus: All features + Full Project Flowchart