RFR(S): 8185694: Replace SystemDictionaryShared::_java_platform_loader with SystemDictionary::is_platform_class_loader()

[Jiangli Zhou]

Hi Calvin,

> On Oct 4, 2017, at 3:32 PM, Calvin Cheung <calvin.cheung at oracle.com> wrote:
> 
> 
> 
> On 10/4/17, 10:45 AM, mandy chung wrote:
>> 
>> 
>> On 10/4/17 10:12 AM, Calvin Cheung wrote:
>>> Mandy, David,
>>> 
>>> Thanks for the review.
>>> 
>>> I've made the change based on your suggestion:
>>> http://cr.openjdk.java.net/~ccheung/8185694/webrev.01/
>> systemDictionary.cpp
>> 
>> SystemDictionary::roots_oops_do and oops_do have to be updated to traverse during GC.
> It is being handled in the following line of code in roots_oops_do():
>  CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)

Since you moved _java_platform_loader to systemDictionary.hpp, please handle that in SystemDictionary::roots_oops_do() and SystemDictionary::oops_do().

> 
> The implementation is in closed source.

Please clean up the closed code to remove those.


Thanks,

Jiangli

>> Is this new java_platform_loader function used anywhere?
> Yes, it is being used in closed source.
>> 
>> Currently SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass is preloaded.  Shouldn't this be removed?  What about jdk_internal_loader_ClassLoaders_AppClassLoader?
> They're being used in lines 184 and 193 in systemDictionary.cpp and also in closed source.
>> 
>> thread.cpp
>> 
>> 3752 SystemDictionary::compute_java_loaders(CHECK_(JNI_ERR));
>> 
>> What is the difference between CHECK_(JNI_ERR) vs CHECK_JNI_ERR?  Should it simply use CHECK_JNI_ERR as in other places?
> They are the same, in utilities/exceptions.hpp:
> #define CHECK_JNI_ERR                            CHECK_(JNI_ERR)
> 
> and it expands to the following:
> __the_thread__); if ((((ThreadShadow*)__the_thread__)->has_pending_exception())) return (-1); (void)(0
> 
> I can change it to CHECK_JNI_ERR.
> 
> thanks,
> Calvin
>> 
>> Mandy