On Mon, Feb 01, 2021 at 03:41:50PM -0300, Vinicius Tinti wrote:
>
> My goal is to avoid having a dead code. Three options come to mind.
>
> The first would be to add another #ifdef SOMETHING (suggest a name).
> But this doesn't remove the code and someone could enable it by accident.
I *really* don't see the point of having the compiler whine about
"dead code", so I'm not terribly fond of
-Wunreachable-code-aggressive. There may be times where depending on
how things are compiled, we *want* the compiler to remove code block,
and it makes the code less ugly than having #ifdef ... #endif breaking
up the code.
If turning that on requires uglifying many places in the kernel code,
maybe the right answer is... don't.
That being said, I have no problem of replacing
if (0) {
...
}
with
#ifdef DX_DEBUG
...
#endif
In this particular place.
But before we go there, I want to register my extreme skepticsm about
-Wunreachable-code-aggressive. How much other places where it is
***obvious*** that the maintainer really knew what they are doing, and
it's just the compiler whining about a false positive?
> > However, if there *is* a bug, having an early detection that the
> > representation invariant of the data structure has been violated can
> > be useful in root causing a bug. This would probably be clearer if
> > the code was pulled out into a separate function with comments
> > explaining that this is a rep invariant check.
>
> Good idea. I will do that too.
If you want to do that, and do something like
#ifdef DX_DEBUG
static inline htree_rep_invariant_Check(...)
{
...
}
#else
static inline htree_rep_invariant_check(...) { }
#endif
I'm not going to complain. That's actually a better way to go, since
there may be other places in the code where a developer might want to
introduce a rep invariant check. So that's actually improving the
code, as opposed to making a pointless change just to suppress a
compiler warning.
Of course, then someone will try enabling a -W flag which causes the
compiler to whine about empty function bodies....
- Ted
