[16] RFR(S): 8247218: Add default constructor to VectorSet to use Thread::current()->resource_area() as arena by default

[Vladimir Kozlov]

Looks good.

Note for others, VectorSet(Arena*) version is left because compiler uses it with an other arena (comp_arena).

resource_area is used per compilation phase or even smaller scopes.
comp_arena is used per one compilation scope.

Thanks,
Vladimir

On 6/18/20 3:36 AM, Christian Hagedorn wrote:
> Hi
> 
> Please review the following cleanup:
> https://bugs.openjdk.java.net/browse/JDK-8247218
> http://cr.openjdk.java.net/~chagedorn/8247218/webrev.00/
> 
> By adding an additional default constructor in VectorSet (as also present in Node_List, Node_Stack etc.), we can replace 
> the often found pattern
> 
>    Arena* a = Thread::current()->resource_area();
>    VectorSet visited(a);
> 
> by a simple
> 
>    VectorSet visited;
> 
> I additionally cleaned up some other places where this pattern was found, for example for Node_List etc.
> 
> Thank you!
> 
> Best regards,
> Christian