[llvm-dev] wasteful cmake defaults

[Robinson, Paul via llvm-dev]

> >     I don't think having this documented is all that helpful.  I know
> that
> >     when I build a new project, if I see it has cmake, I just do cmake -
> G
> >     Ninja && ninja and don't bother reading the docs.
> >
> >     I think it would make the most sense to change the default to be
> >     Release+Asserts, because this is the most likely configuration to
> work
> >     on the average system.
> >
> >
> > Can you expand on why release+asserts and not just release?
> > I can imagine folks just wanting to try clang out of the box and finding
> > it "slow" because they don't know that assertions have to be disabled
> > explicitly for example.
> > Of course developers have to opt-in assertions, but they also have to
> > think about opting in Debug info and sanitizers.
> >
> 
> The reason I prefer enabling asserts is because it gives you better
> information when something goes wrong, and I think this can be helpful
> for new users.  But this is just a slight preference, I would support
> either Release+Asserts or Release as the default.
> 
> -Tom

FWIW, within Sony our wrapper build script defaults to Release+Asserts.

We could default to Release+Asserts if the build type is empty; but if
it's not empty, we do what you asked (and Release would not imply Asserts).

Has anyone measured the compiler performance difference for +Asserts lately?
I have a vague memory that it was ~10% but that was quite a while ago.
--paulr