[PATCH] D120540: [Driver] Enable to use C++20 modules standalone by -fcxx-modules

[Iain Sandoe via Phabricator via cfe-commits]

iains added a comment.

I'm not sure it is exactly chaos, but it is certainly fragile and somewhat hard(er than necessary) to maintain.

We (@ChuanqiXu  and I at least) agree that there should be some way to make "which modules mode" unambiguous in both the driver and the compiler (I think we're only debating how/which flag to use)

The end game objective is that "when the compiler is processing for C++20 or later, then it should default to C++20+ modules". 
IMO, knowing "which modules mode" is in force does not alter this - if anything it ought to simplify checking whether we have completed migration (whatever that ends up meaning).

Presumably, we are never going to delete the other options (e.g. -fmodules etc) they would (perhaps) become deprecated and then "do nothing". OTOH, perhaps that mode will be needed by existing users for some considerable time.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D120540/new/

https://reviews.llvm.org/D120540