RFR (S) 8228630: Remove always true parameter to NoSafepointVerifier

[David Holmes]

Hi Coleen,

On 31/07/2019 6:45 am, coleen.phillimore at oracle.com wrote:
> Summary: Also remove NoGCVerifier since NoSafepointVerifier covers GC 
> checking when not already at a safepoint and is a stronger check.

It wasn't at all clear to me that we may not want a NoGCVerifier that is 
independent of safepoints e.g. for use in a non-JavaThread. But AFAICS 
we don't use NoGCVerifier directly, but only via NoSafepointVerifier - 
in which case the "no safepoint" check subsumes the "no gc" check and 
the whole thing collapses to what you have (which results in a nice 
amount of code deletion!).

It took me a while to follow through all the changes but it seems good.

I spotted this reference to NoGCVerifier:

./share/opto/runtime.cpp:// Thus, it cannot be a leaf since it contains 
the NoGCVerifier.

I'm not at all sure that the rest of the comment related to this is 
accurate any more - the reference to the NoGCVerifier didn't make sense 
to me.

Thanks,
David
-----

> See bug for more details also.  Tested with all jtreg 
> runtime,compiler,serviceability and gc tests.  Also hs-tier1-3 on 
> linux-x64-debug.
> 
> open webrev at http://cr.openjdk.java.net/~coleenp/2019/8228630.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8228630
> Thanks,
> Coleen