Question about source-to-source compilation

[Thomas Bernard]

Hello all,

As far as I know, GCC 4.x is easily retargetable for a new architecture. 
I would be interested by source-to-source compilation with the GCC 
framework. For instance, let's say the input language is C and the 
output language is C annotated with pragmas which are the results of 
some code analysis (done at middle-end level). I do not think that the 
GCC back-end could support a programming language such as C, C++ or Java.
Is GCC 4.x designed to source-to-source compilation ? Is that possible 
or do I miss something here ?

Thanks in advance,
T.