I have published this to the gcc mailling list
James Michael DuPont - Linkage of GPLed GCC to Closed Source via XML or Perl Dear GCC Developers,

For the past three years, I have been working on a
project to create a object oriented interface to the
GCC compiler, the GCC Node Introspector
(http://introspector.sourceforge.net/).

This turned from a c into a Perl project after
realising the power of Perl for handling strings and
complex data structures.
Currently I am using a modified version of c-dump.c
like done in CPPX
(http://swag.uwaterloo.ca/~cppx/doc/cppx/arch.html). I
output the tree nodes into a XML form that is very
similar to the tree dump, just with xml syntax. This
is streamed into a Perl program via popen and written
to a Postgres database.