Find all occurrences of a function in Eclipse

Use Ctrl+Shift+G for search the whole workspace

Select a method and hit Ctrl+Alt+H to open its Call Hierarchy which will show you where the method is being called from.

You can find a menu entry in the context menu, when right clicking on the function. You can also press Ctrl+G when the cursor is above the function or member. Not every project and file type supports this feature. For example, EPIC Perl only supports finding the definition of a function.