tree 4cc5217ae73035a56f6a5f5923b4d11a8fdeac7d
parent aac4647e6eb7c04d34e7d8fbdab08efa8ba079a4
author John Cuthbertson <johnc@openjdk.org> 1302195200 -0700
committer John Cuthbertson <johnc@openjdk.org> 1302195200 -0700

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error

A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.

Reviewed-by: kvn, iveresov, never, tonyp, dholmes