Can I dump list of macro defines used from clang preprocessor

Clang Frontend
1

I’m trying to come up with some smart recompile logic for defines given via command line arguments.

To do this, it would be nice if clang could write out to a file what macro defines it used from the command line, or what macro defines it checked existence of

is this possible? thanks

To be clear, I am not asking to dump pre-defined macros, or get the preprocessor output

2

-E -dM

3

Right, so I am not asking to dump pre-defined macros, or get the preprocessor output

Let me be more specific

If I have source code that is like this:

#ifdef USE_FOOBAR
...
#endif

and compile it with

-DUSE_FOOBAR -DUSE_OTHER

I would like Clang to tell me that the source code used the define USE_FOOBAR