for review: 8236522: "always atomic" modifier for inline classes to enforce atomicity

[John Rose]

I’ve come back around to this feature, after (SMH) realizing
it should be a marker interface (java.lang.NonTearable) instead
of a new modifier and access flag.  Thanks, Brian…

Also, I’ve re-integrated my changes on top of the signature
changes and field layout changes.

Please have another look:

http://cr.openjdk.java.net/~jrose/values/atomic-8236522

(Old webrev is atomic-8236522.1)

— John

P.S. There’s a slightly over-engineered string matcher included.
I intend to use it for other purposes as well, when there are
ad hoc class lists to assign special properties to, such as
“please track locking events” and so on.  The code in
CompilerOracle was not repurposable, sadly.

> On Feb 12, 2020, at 7:36 AM, Tobias Hartmann <tobias.hartmann at oracle.com> wrote:
> 
> Hi John,
> 
> I've just sent the RFR for 8238780 which will fix these issues. I found one additional place where a
> StoreStore barrier was missing.
> 
> Thanks,
> Tobias
> 
> On 22.01.20 21:20, John Rose wrote:
>> On Jan 20, 2020, at 6:54 AM, Tobias Hartmann <tobias.hartmann at oracle.com
>> <mailto:tobias.hartmann at oracle.com>> wrote:
>>> 
>>>> 
>>>> How did it reproduce for you? It would be nice to have a regression test.
>>> 
>>> Okay, -XX:+StressLCM did the trick :)
>> 
>> Thanks for taking it out for a spin.
>> 
>> The jtreg test ValueTearing.java failed reliably (P ~ 50%)
>> on my MacBook.  Debugging that led me to add that S-S barrier.
>> 
>> — John