ccglue is a complementary tool to cscope and ctags. The tool builds a cross-reference symbol database from cscope [and ctags] databases that can be used to display dependency-graphs (aka call-trees, code flow). Visualization can be done with the Vim CCTree plugin (http://www.vim.org/scripts/script.php?script_id=2368), or the built-in stand-alone command-line tracer.