[PATCH] clang: forward -no-integrated-as from the driver

[Rafael Espíndola]

> I'm very wary of that approach. Surely the use case for inline assembly,
> almost by *definition*, is that we're doing something that the compiler
> doesn't understand and/or doesn't get right.
>
> We don't want it looking inside and thinking it knows best, even in the
> case where it *is* going to see instructions that it actually knows
> about. Perhaps *especially* in that case.
>
> But I suppose the specific case you mention, of checking constraints,
> could have some merit. Even if the compiler takes a strictly "hands-off"
> approach and doesn't screw with the output in any way, it could still
> *see* that it's using instructions which clobber certain registers, and
> then give a warning if those clobbers are missing.
>
> But unless it's actually *using* the integrated assembler, if it can't
> parse what's in the inline asm, the failure mode should be that it just
> does nothing and doesn't manage to emit any such warnings.
>
> It certainly shouldn't bail out with an error, which is the subject of
> bug 18891.

OK, this is going a bit off topic for this code review. What this
patch does is disable the integrated assembler completely when
-no-integrated-as is given. Both for -S and -c. I think you agree that
that is the correct behavior.

Another possible change would be for the driver to make -S imply
-no-integrated assembler. That is far more contentious and should have
a code review of its own.

Cheers,
Rafael