Caller/called graph

If I am using an editor such as Eclipse to analyze a large PHP system and I want to find the file that a function is declared in then I can search for it. I think that the (right-click) context menu for the function sometimes has an item to open the declaration but that does not always work. The same for an include statement; even if I don't know what the path will be during execution and even if the source is in multiple folders, I can search for the file. For large systems however all that can take time (my time). Is there a tool that can process thousands (at least a couple thousand) files and produce data of what file that a called function exists in and where a function is called from? In other words, caller/called data. I understand the technical challenges. In PHP includes are processed during execution so I know it might not be possible but I am asking if there is anything that can do it as much as possible. I searched the mailing list for "caller called" and found nothing, I apologize if this has been asked before.