RFR: 8155678: ClassLoader::initialize_module_loader_map should only be called when dumping CDS archive

[Jiangli Zhou]

Hi Calvin,

> On May 3, 2016, at 4:42 PM, Jiangli Zhou <jiangli.zhou at Oracle.COM> wrote:
> 
> Hi Calvin,
> 
>> On May 3, 2016, at 4:32 PM, Calvin Cheung <calvin.cheung at oracle.com> wrote:
>> 
>> Hi Jiangli,
>> 
>> Just a minor comment in classLoaderExt.hpp:
>> 
>> 58           jshort classloader_type = ClassLoader::classloader_type(
>> 
>> How about u2 instead of jshort?
> 
> I agree. u2 is a better choice here. Will change it.

I spoke too soon. InstanceKlass::set_class_loader_type() sets the loader type bits in '_misc_flags’ based on the ‘loader_type’ argument value. InstanceKlass has a method named loader_type(), which returns a u2 value. Note the u2 value returned by InstanceKlass::loader_type() is different from the ClassLoader::ClassLoaderType. The name of the InstanceKlass::loader_type() is missing leading, it’s better to be renamed. I’ll handle that separately.

‘jshort’ is the same a ‘s2’’. To be consistent, I changed above ‘jshort’ to be ‘s2’, since ClassLoader.classloader_type() returns s2.

Here is the updated webrev: http://cr.openjdk.java.net/~jiangli/8155678/webrev.01/

Thanks,
Jiangli

> 
> Thanks,
> Jiangli
> 
>> 
>> It is because in set_class_loader_type(), we are setting the _misc_flags which is of type u2.
>> 
>> If you make the above change, you'll need to change set_class_loader_type() as well.
>> 
>> thanks,
>> Calvin
>> 
>> On 5/3/16, 3:59 PM, Jiangli Zhou wrote:
>>> Please review the following changes that make ClassLoader::initialize_module_loader_map() CDS dump time only. The module to loader map is not used by CDS runtime, so this avoids the unnecessary overhead for runtime. As part of the changes, I moved the ClassLoader::class loader_type() call from ClassLoader::load_class() into ClassLoaderExt::Context::record_result(), since ‘class loader_type’ is only needed by record_result(). That allows ClassLoader::class loader_type() become a CDS only API.
>>> 
>>> webrev: http://cr.openjdk.java.net/~jiangli/8155678/webrev.00/
>>> bug: JDK-8155678<https://bugs.openjdk.java.net/browse/JDK-8155678>
>>> 
>>> Thanks,
>>> Jiangli
>