How to compare thecaller thread object and callee's holder?

[David Holmes]

Tony,

Tony Guan said the following on 04/22/10 00:06:
> a quick question: given a caller thread object( JavaThread* thread)
> and the method to be called by the thread (methodOopDesc* method), how
> do I know that the holder of the "method" is from the same caller
> object or not?

I don't understand what you mean here by "holder"?

> The reason why I am asking is:
> in
>  JRT_LEAF(int, SharedRuntime::dtrace_method_entry(    JavaThread*
> thread, methodOopDesc* method)) in shareRuntime.cpp
> 
> I want to check if the method called will start another thread or not,
> so I need to compare the holders of the caller and callee.

Again I don't know what the "holder" is here. If a method starts a 
thread then that new thread doesn't necessarily have any connection back 
to the method from which it was started.

> So one more question: is there any other way to achieve this?

I think you would have to add code in the thread start routine (of the 
JVM) and have the before/after method hooks to do this eg:

  before-method:  set flag showing current thread is interested in 
thread start
  start-thread: check if current thread interested in thread start and 
if so bump a counter
  after-method: check counter and clear flag

David Holmes