Caller/called graph

[Sam Hobbs <Sam@xxxxxxxxxxxxxxxxxx>]

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.