We have a CORBA implementation that autogenerates Java and C++ stubs for us. Because the CORBA-generated code is difficult to work with, we need to write wrappers/helpers around the CORBA code. So we have a 2-step code generation process (yes, I know this is bad):
CORBA IDL -> annoying CORBA-generated code -> useful wrappers/helper functions
Using Java's reflection, I can inspect the CORBA-generated code and use that to generate additional code. However, because C++ doesn't have reflection, I am not sure how to do this on the C++ side. Should I use a C++ parser? C++ templates?
TLDR: How to generate C++ code using generated C++ code as input?
Have you considered to take a step back and use the IDL as source for a custom code generator? Probably you have some wrapper code that hides things like duplicate, var, ptr, etc. We have a Ruby based CORBA IDL compiler that currently generates Ruby and C++ code. That could be extended with a customer generator, see https://www.remedy.nl for RIDL and R2CORBA.
Another option would be to check out the IDL to C++11 language mapping, more details on https://www.taox11.org. This new language mapping is much easier to use and uses standard types and STL containers to work with.