On Wed, 25 Nov 2020 19:48:40 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>>> I just pulled the fresh master, applied this patch on top, enabled >>> `_PhantomReference_refersTo0` in `c2compiler.cpp`, and ran >>> `CONF=linux-x86_64-server-fastdebug make images run-test TEST=tier1 >>> TEST_VM_OPTS="-XX:+UseShenandoahGC"` without problems. >>> >>> @vnkozlov, what Shenandoah failure did you see? Attention @rkennke. >> >> @shipilev 2 new tests added by JDK-8188055 does not trigger C2 compilation. >> You need to run my new test to trigger problem I see: >> >> java -Xbatch -XX:-TieredCompilation -XX:CICompilerCount=1 >> -XX:+UseShenandoahGC TestReferenceRefersTo.java >> >> # Internal Error >> (/open/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp:999), >> pid=2498681, tid=2498694 >> # assert(!is_narrow) failed: phantom access cannot be narrow >> # >> # JRE version: Java(TM) SE Runtime Environment (16.0) (fastdebug build >> 16-internal+0-2020-11-24) >> # Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug >> 16-internal+0-2020-11-24, mixed mode, sharing, compressed oops, shenandoah >> gc, linux-amd64) >> # Problematic frame: >> # V [libjvm.so+0x1862090] >> ShenandoahBarrierC2Support::call_lrb_stub(Node*&, Node*&, Node*, Node*&, >> Node*, unsigned long, PhaseIdealLoop*)+0x7e0 > >> @shipilev 2 new tests added by JDK-8188055 does not trigger C2 compilation. > > That sounds like a testbug to me! Since this PR adds C2 intrinsics, I thought > it is expected that new tests trigger it in default test configs... > >> You need to run my new test to trigger problem I see: >> >> ``` >> java -Xbatch -XX:-TieredCompilation -XX:CICompilerCount=1 >> -XX:+UseShenandoahGC TestReferenceRefersTo.java >> >> # Internal Error >> (/open/src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp:999), >> pid=2498681, tid=2498694 >> # assert(!is_narrow) failed: phantom access cannot be narrow >> # > > Right. So new intrinsic introduces the "phantom" access from C2 intrinsic > code, and it can be narrow. Shenandoah did not handle that path, because no > existing code shapes were exercising it, and it was considered dead. Since it > is not dead now, we can simply implement that part like this: > http://cr.openjdk.java.net/~shade/shenandoah/8256999-shenandoah-fix.patch. Your PR have also been bitten by #1427, merge from master to get it fixed. ------------- PR: https://git.openjdk.java.net/jdk/pull/1425
