RFR: 8200550: Xcode 9.3 produce warning on heapRegionSet.hpp

[Thomas Schatzl]

Hi,

On Mon, 2018-04-09 at 02:55 -0400, Kim Barrett wrote:
> > > NOT_PRODUCT/#ifndef PRODUCT is the wrong choice, being contrary
> > > to to the intent of an optimize build to be similar in
> > > performance characteristics to a product build.
> > 
> > In my understanding there is an additional clause in that sentence:
> > "[...] to a product build, including some extra verification".
> > 
> > There is lots of similar verification that uses
> > PRODUCT_RETURN/#ifndef PRODUCT that also already changes
> > performance characteristics for an optimized build.
> > See the other PRODUCT_RETURN uses (I can find 107 in just the gc
> > directory) in this and other files.
> 
> That's not my understanding from discussions with Jon Masamitsu (who
> was the only person I knew of to regularly use and care about
> "optimized" builds).  But it is certainly true there is a lot of code
> that violates that rule.  I occasionally wonder whether anyone would
> care or notice if we killed off "optimized" builds; we don't test
> that mode, with the result that it is often broken.

I agree that we may probably just remove optimized builds for the above
stated reasons, but that is another discussion :)

> > So yes, I recommend removing this capability in this instance. This
> > verification does not seem to be any different than any other.
> > 
> > Not sure if this capability is too expensive or not (this is
> > typically a bit fuzzy), but in the worst case one can use
> > NOT_DEBUG_RETURN.
> 
> Since it was previously only under ASSERT, I'm leaving it that way.
> 
> New webrevs:
> full: http://cr.openjdk.java.net/~kbarrett/8200550/open.01/
> incr: http://cr.openjdk.java.net/~kbarrett/8200550/open.01.inc/

  looks good.

Thanks,
  Thomas