Excerpt:

"Clang can serialize its AST out to disk and read it back into another program, which is useful for whole program analysis.

GCC does not have this. GCC's PCH mechanism (which is just a dump of the compiler memory image) is related, but is architecturally only able to read the dump back into the exact same executable as the one that produced it (it is not a structured format)."

Clang, you had me at 'hello'.

The point I outlined above is just icing on the cake!