But you aren't parsing the program. You're parsing a particular instantiation of the program for a particular set of -D defines and include files. Whole chunks of the program that were excluded by #ifdefs don't get parsed at all.
This is fine if you just want to analyze that particular instance of what the program can become, but it's not fine if you're trying to do something to the program as a whole.
This is fine if you just want to analyze that particular instance of what the program can become, but it's not fine if you're trying to do something to the program as a whole.