RFR (XS) 8156068: Unsafe.{get|set}Opaque should be single copy atomic

Aleksey Shipilev aleksey.shipilev at oracle.com
Thu May 5 19:06:44 UTC 2016


Please review a tiny fix in C2 intrinsics that make
Unsafe.{get|set}Opaque single-copy atomic, as intended. These opaque
methods are supposed to act like std::atomic(..., memord_relaxed), that
is, do not induce ordering, but still provide access atomicity.

Interpreter and C1 are delegating to volatile get/set, and so are atomic
already. C2 has a little bug that was introduced along with the initial
VarHandles change.



Testing: jcstress atomicity test on 32-bit x86; RBT (hs-tier0-comp).


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