RFR: 5043030 (reflect) unnecessary object creation in reflection

[Andrej Golovnin]

Hi David,

>> 
>> The valueOf calls may also allocate a new object so you can't just
>> delete the JvmtiExport::post_vm_object_alloc call. Unfortunately you
>> can't tell whether a new object was allocated or not. It is only for the
>> smaller primitive types that any kind of Object caching is mandated.
> 
> It is only for the smaller values (-128 to +127) of the integer primitives types (plus boolean) that caching is mandated. Float.valueOf and Double.valueOf always create objects.
> 

You are right, that #valueOf call may allocate an object.
But as far as I understand currently the JvmtiExport::post_vm_object_alloc call
is only needed, because today the native code itself allocates an object
by calling java_lang_boxing_object::create(type, value, CHECK_NULL);.

My code changes this behavior and delegates object allocation back to Java
by calling 

  JavaCalls::call_static(&boxed_value,
                         klass_handle,
                         vmSymbols::valueOf_name(),
                         valueOf_signature,
                         &args,
                         THREAD);

But maybe I misunderstood the implementation of JavaCalls.

Best regards,
Andrej Golovnin