Why does "jobject" on interpreter stack point to wield locations?

[Colin(Du Li)]

Thanks  a lot, Tom.
You are right!
But the question is when the stack use jobject? The method signature in the
previous example is "virtual jobject
 java.lang.ClassLoader.loadClass(jobject)", which is quite confusing.
I know one possible answer is when the method is a "native" method, it will
use jobjects instead of raw reference.  
However, I have observed it for a while. For the native method, stack
sometimes uses jobject, sometimes use raw references. Is my observation
right?
All in all, how can I tell the reference on the stack is raw reference or
jobject?
Thanks again!

Colin

Tom Rodriguez wrote:
> 
> That interpreter stack doesn't use jobjects.  It contains raw  
> references to Java objects so just use them directly.
> 
> tom
> 
> On Apr 13, 2009, at 9:21 PM, Colin(Du Li) wrote:
> 
>>
>> Hello.
>> I'm playing with stack of c++ interpreter. I have some questions  
>> about the
>> object reference on the stack.
>> Let's look at the following example:
>> When interpreter invoke("invokespecial") method  "virtual jobject
>> java.lang.ClassLoader.loadClass(jobject)", I print out stack frame  
>> (last
>> frame), and the result is as follows:
>>
>> - local  [0x7e747b90] ; #0
>> - local  [0x7e7489d0] ; #1
>> - stack  [0x7e7489d0] ; #1
>> - stack  [0x7e747b90] ; #0
>> [ - obj
>> a 'sun/misc/Launcher$AppClassLoader'
>> - lock
>> monitor
>> - monitor[0xbff3f8c8]
>> - bcp    [0xb3f3fa4e] ; @2
>> - locals [0xbff3f944]
>> - method [0xb3f3fa78] ; virtual jobject
>> java.lang.ClassLoader.loadClassInternal(jobject)
>>
>> According to the jvm specification, stack slot #0 should contain the
>> "receiver", and stack slot to the parameter of method  
>> "loadclass(jobject)".
>> I use JNIHandles::resolve(obj) to resolve the two jobjects on the  
>> above
>> stack slot. The result of slot #0 is a reference pointing to another  
>> slot of
>> the current stack. The result of slot #1 is a invalid address, "0x1".
>> The results confuse me. I assumed both of them pointed to some  
>> object is
>> heap.
>> Could you give me some explanation for this question?
>> I really need your help.
>> Thanks a lot!
>>
>> Colin.
>> -- 
>> View this message in context:
>> http://www.nabble.com/Why-does-%22jobject%22-on-interpreter-stack-point-to-wield-locations--tp23033048p23033048.html
>> Sent from the OpenJDK Hotspot Virtual Machine mailing list archive  
>> at Nabble.com.
>>
> 
> 
> 

-- 
View this message in context: http://www.nabble.com/Why-does-%22jobject%22-on-interpreter-stack-point-to-wield-locations--tp23033048p23043577.html
Sent from the OpenJDK Hotspot Virtual Machine mailing list archive at Nabble.com.