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

[Calvin Cheung]

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);)

The implementation is in closed source.
> 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