Question: finding out a function return type

[Fredrik Warg]

Hi,

I'm trying to make a small modification to gcc,
but I'm having trouble trying to figure out how
the parse tree is built up.

What I want to do is to get the return type of
each function/method (actually it is enough to know
if the return type is void or something else).

The reason is that I want to output an extra
assembly instruction in each function prologue
(these are "ques" to a simulator I'm running
the programs on top of).

Where can I find information about the return
type of a function? Can anyone at least point
me in the right direction?

Note that I'm quite new to the gcc source so
don't assume I know how things fit together...

thanks,
Fredrik