[13] RFR (S): 8218874: C2: Unsafe to access PhaseIdealLoop outside of constructors

[Vladimir Kozlov]

There was problem with RM when run with -XX:+VerifyLoopOptimizations. 
Please, check that. Otherwise it looks good.

Thanks,
Vladimir K

On 2/12/19 3:15 PM, Vladimir Ivanov wrote:
> http://cr.openjdk.java.net/~vlivanov/8218874/webrev.00/
> https://bugs.openjdk.java.net/browse/JDK-8218874
> 
> It's unsafe to access PhaseIdealLoop outside of its constructors: its 
> internal data structures may be corrupted because 
> PhaseIdealLoop::build_and_optimize() allocates some of them under local 
> ResourceMark.
> 
> Proposed fix is:
>    * use caller scope for memory allocation (as other Phases do);
>    * to simplify PhaseIdealLoop usage, introduce static method 
> optimize() and allocate PhaseIdealLoop there prepended by ResourceMark;
> 
> Testing: hs-precheckin-comp, tier1-5
> 
> Best regards,
> Vladimir Ivanov