6716785: implicit null checks not triggering with CompressedOops
Summary: allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check
Reviewed-by: kvn, jmasa, phh, jcoomes
1cc8dd79fd1cd13d36b385196271a29632c67c3b jdk7-b24
bf2517e15f0c0f950e5b3143c4ca11e2df73dcc1 jdk7-b25
5ae7db536e3fcf6be78e45b240a9058095e0ed38 jdk7-b26
67052ac87fc927d048e62ec54ff42adb230d3f7c jdk7-b27
18dc4ba4739a537fd146f77da51db16efce28da2 jdk7-b28
bfe4572fd301a6fcd120373cdb2eff5d2da0c72c jdk7-b29
bee4731164a06ddece1297ae58db24aca6a1c626 jdk7-b30