Request for reviews (S): 7148109: C2 compiler consumes too much heap resources

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/7148109/webrev

7148109: C2 compiler consumes too much heap resources

RA may use a lot of native memory when C2 compiles big method with a lot of 
branches and simultaneous live date. For each (spill, split) cycle RA allocates 
arrays in Split() method with size "sizeof(p*)*num_blocks*spill_cnt" and does 
not free resource on method exit. With  _num_blocks == 1000 and spill_cnt == 500
RA will use more then 5Mb of additional native memory for each cycle. RA will do 
up to 24 cycles before bailout so it can consume more then 100Mb by one C2 
compiler thread.

Add split_arena to allocate these arrays and free them on method's exit.

Thanks,
Vladimir