RFR: 8251850: Simplify ResourceMark constructors using delegation

[Kim Barrett]

> On Aug 17, 2020, at 9:45 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Hi,
> 
> On 17.08.20 04:24, Kim Barrett wrote:
>>> On Aug 15, 2020, at 8:31 AM, Kim Barrett <kim.barrett at oracle.com> wrote:
>>> 
>>>> On Aug 14, 2020, at 10:29 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
>>>> 
>>>> Please review this simplification of the constructors for ResourceMark,
>>>> accomplished using delegating constructors.
>>>> 
>>>> Also made the constructors "explicit" and the class non-copyable.
>>>> 
>>>> CR:
>>>> https://bugs.openjdk.java.net/browse/JDK-8251850
>>>> 
>>>> Webrev:
>>>> https://cr.openjdk.java.net/~kbarrett/8251850/open.00/
>>>> 
>>>> Testing:
>>>> mach5 tier1
>>> 
>>> I should have looked further along in resourceArea.hpp. All the
>>> changes I made to ResourceMark? DeoptResourceMark should have similar
>>> changes made to it.
>>> 
>>> Well, I have a first round of comments from the ResourceMark changes.  I can
>>> take those into account for DeoptResourceMark.
>> This ended up engendering a fairly substantial revision.  I've taken at
>> least some of Thomas's comments into account along the way.
>> Changed ResourceMark and DeoptResourceMark to share ResourceMarkImpl, which
>> provides most of the implementation of both, eliminating the copy-paste-modify
>> "reuse" that used to be there.
>> Moved all of the state capture and rollback support into ResourceArea. The
>> mark objects include a captured state object and pass that back to the
>> ResourceArea when doing rollbacks.
>> Cleaned up the _nesting checking.
>> Removed nonsensical ResourceArea::_warned.
>> Maybe I should change the bug summary from
>> "Simplify ResourceMark constructors using delegation"
>> to something like
>> "Refactor ResourceMark and DeoptResourceMark for better code sharing"
> 
> Please do.

Done.

> 
>> New webrevs:
>> full: https://cr.openjdk.java.net/~kbarrett/8251850/open.01/
>> incr: https://cr.openjdk.java.net/~kbarrett/8251850/open.01.inc/
>> Testing:
>> mach5 tier1-3
>> local hotspot:tier1 with -XX:+UseMallocOnly
>> local hotspot:tier1 with -XX:+ZapResourceArea
>> Note that compiler/loopopts/TestDeepGraphVerifyIterativeGVN.java times out
>> when run with -XX:+UseMallocOnly, with or without these changes.
> 
>  looks good.
> 
> Thomas

Thanks.