Request for review: 7172967: Eliminate the constMethod's _method backpointer to the methodOop

[Jiangli Zhou]

Hi,

Please review the following webrev that eliminates the _method 
backpointer from constMethod. The constantPoolOop pointer is moved from 
methodOop to constMethod, so there is still enough information to map 
from constMethod back to methodOop.

   http://cr.openjdk.java.net/~jiangli/7172967/webrev.00/

Tested with jprt, runtheses and vm.quick.testlist. No performance 
degradation in specjbb2005 and specjvm98. Your review and comments very 
appreciated.

============================================================================== 

logs.method_baseline.1:
   Benchmark           Samples        Mean     Stdev             Geomean 
Weight
   specjbb2005               8    56127.57    488.69
   specjvm98                 8      537.57     14.89
============================================================================== 

logs.method.1:
   Benchmark           Samples        Mean     Stdev   %Diff     P  
Significant
   specjbb2005               8    56733.04    549.11    1.08 
0.036            *
   specjvm98                 8      538.45     19.90    0.16 
0.922            *
============================================================================== 


Thanks,

Jiangli