RFR: 8035746: Add missing Klass::oop_is_instanceClassLoader() function (original) (raw)

Stefan Karlsson stefan.karlsson at oracle.com
Wed Feb 26 13:17:31 PST 2014

On 2014-02-26 22:16, Coleen Phillimore wrote:

Okay with below. Thanks for pointing out the code that could be changed - I agree, they are not really worth doing.

Thanks again, Coleen.

StefanK

Coleen

On 2/26/2014 3:32 PM, Stefan Karlsson wrote: On 2014-02-26 20:38, Coleen Phillimore wrote: On 2/25/2014 12:50 PM, Stefan Karlsson wrote:

On 2014-02-25 15:15, Mikael Gerdin wrote:

Hi Stefan,

On Tuesday 25 February 2014 14.43.49 Stefan Karlsson wrote: Hi all,

Please, review this small patch to add Klass::oopisinstanceClassLoader(). Webrev: http://cr.openjdk.java.net/~stefank/8035746/webrev.00 Code change looks good. Thanks.

There are a couple of places where we check whether or not a Klass is a ClassLoader, something like: if (klass->issubclassof(SystemDictionary::ClassLoaderklass())) These places could now be changed to klass->oopisClassLoader(), saving a possibly expensive subtype check. Should we file an RFE to change these or do you want to change them straight away? I'd prefer a separate RFE. This change looks good. Thanks. I assume this is actually for G1 class unloading. Yes. Too bad though I wish you'd change it all in one pass. I just wanted to bring over this small change from the G1 Class Unloading repository and not have to argue whether changing the usages issubclassof to oopisinstanceClassLoader was worth it or not. I did a quick search for this and found these three usages: 1) src//share/vm/classfile/javaClasses.hpp- static bool issubclass(Klass* klass) { src//share/vm/classfile/javaClasses.hpp: return klass->issubclassof(SystemDictionary::ClassLoaderklass()); src//share/vm/classfile/javaClasses.hpp- } which is unused, AFAICT. 2) src//share/vm/prims/jvm.cpp: if (!vfst.method()->methodholder()->issubclassof(SystemDictionary::ClassLoaderklass())&& src//share/vm/prims/jvm.cpp- !vfst.method()->methodholder()->issubclassof(accesscontrollerklass) && src//share/vm/prims/jvm.cpp- !vfst.method()->methodholder()->issubclassof(privilegedactionklass)) { I don't think this helps the readability of the code if we change it. I don't know if this is performance critical. thanks, StefanK Thanks, Coleen thanks, StefanK /Mikael RFE: https://bugs.openjdk.java.net/browse/JDK-8035746 thanks, StefanK

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