Hi David, I understand, Klass types are no longer oops but JNIHandles::resolve_non_null() would expose naked oops. In other words, KlassOops are no longer oops but java.lang.Class objects are.
Thanks, Leela On Thu, Jul 28, 2016 at 10:51 PM, David Holmes <david.hol...@oracle.com> wrote: > Hi Leela, > > On 29/07/2016 12:59 PM, Leela Mohan wrote: > >> I think, change in the file unsafe.cpp is incorrect. ( >> http://cr.openjdk.java.net/~coleenp/6642881_8u40_hotspot/ ) >> >> Below function is accessing naked oops when thread has transitioned to >> "native": >> >> *+ static jobject get_class_loader(JNIEnv* env, jclass cls) {**+ if >> (java_lang_Class::is_primitive(JNIHandles::resolve_non_null(cls))) >> {**+ return NULL;**+ }**+ Klass* k = >> java_lang_Class::as_Klass(JNIHandles::resolve_non_null(cls));**+ oop >> loader = k->class_loader();**+ return JNIHandles::make_local(env, >> loader);**+ }* >> > > klass types are no longer oops in the Java heap, but metaspace objects > that reside in a per-classloader allocation region. They never get > compacted or relocated so raw pointers to them are safe. > > Cheers, > David > > > >> - Leela >> >> On Mon, Sep 8, 2014 at 7:05 PM, Coleen Phillimore < >> coleen.phillim...@oracle.com> wrote: >> >> >>> Thanks, Mandy! >>> >>> Coleen >>> >>> >>> On 9/8/14, 6:59 PM, Mandy Chung wrote: >>> >>> Thumbs up. >>>> >>>> Mandy >>>> >>>> On 9/5/2014 12:55 PM, Coleen Phillimore wrote: >>>> >>>> Summary: Add classLoader to java/lang/Class instance for fast access >>>>> >>>>> This is a backport request for 8u40. This change has been in the jdk9 >>>>> code for 3 months without any problems. >>>>> >>>>> The JDK changes hg imported cleanly. The Hotspot change needed a hand >>>>> merge for create_mirror call in klass.cpp. >>>>> >>>>> http://cr.openjdk.java.net/~coleenp/6642881_8u40_jdk/ >>>>> http://cr.openjdk.java.net/~coleenp/6642881_8u40_hotspot/ >>>>> >>>>> bug link https://bugs.openjdk.java.net/browse/JDK-6642881 >>>>> >>>>> Ran jdk_core jtreg tests in jdk with both jdk/hotspot changes. Also ran >>>>> jck java_lang tests with only the hotspot change. The hotspot change >>>>> can >>>>> be tested separately from the jdk change (but not the other way >>>>> around). >>>>> >>>>> Thanks, >>>>> Coleen >>>>> >>>>> >>>> >>>> >>>
