[cfe-dev] Language not recognized: 'c++-module-cpp-output'

[Boris Kolpackov via cfe-dev]

David Blaikie <dblaikie at gmail.com> writes:

> Does this actually speed up clang in an observable way?

I haven't measured, but I very much doubt there will be any significant
speedup if you are going all the way to the object code, so to speak.
The benefit will come if you want to send the file for compilation on
a remote host. In this case you won't need to start the compiler locally
at all.


> What makes it more likely for modularized code? In the sense that many more
> source files won't /need/ to use the preprocessor, so they're sort of
> quasi-preprocessed (trivially, in the sense that there's no work to do)
> already?

Yes, exactly. They won't need #include's and quite a bit of code could
probably be written without relying on macros (especially so for module
interface units).

One hold out is assert(). Maybe it can be done as a compiler intrinsic?

Boris