Hi Andrew,
Oh, you mean the front end dump. Most of the dumps look like this:
Ok... I had a look at the other dumps and can see things more clearly here. Each one of these is a tree node, and links are replaced by numbers of
the form @N. After that, it's just tree nodes. Most of the meaning of these nodes is documented in gcc/tree.def, but a few nodes are language-specific and are documented in the language front ends.
Cheers,David.