Thomas.Rodriguez at Sun.COM
Thu Jul 3 11:33:08 PDT 2008
InterpreterRuntime::resolve_invoke would be a good instrumentation
point, though you'd have to modify the code in the generated
interpreter to always enter that code instead of only the first time a
call site is resolved. Start in the code for
TemplateTable::_invokevirtual and friends and step through that code
to see how it works. Obviously you'd have to disable the compilers
since your trick only works in the interpreter.
Have you considered using bytecode rewriting to capture whatever it is
On Jul 3, 2008, at 11:11 AM, Nagy Mostafa wrote:
> Thanks, Tim.
> Yes, I know I can use JVMTI for the task, but I also wanted to
> collect call-site and some other specific info (e.g. field access)
> information. Can the JVM pass information about call site bytecode
> index/pointer to JVMTI ?
> - nagy
> On Wed, Jul 2, 2008 at 3:05 PM, Tim Bell <Tim.Bell at sun.com> wrote:
> Nagy1981 wrote:
> Hi, I am trying to modify the hotspot interpreter to collect some
> profile data.
> The main thing I want to do is build a call-tree. I want to add a
> hook to
> the interpreter whenever an invoke_* bytecode operation is about to
> such that my call-tree gets updated. Can you please guide me to the
> part of
> the code where control is passed from the interpreter to the
> assembly code
> corresponding to a bytecode operation. All I can find is parts where
> assembly code get generated, but I can't figure out where it is
> Have you looked at the javadoc for the JVMTI_EVENT_METHOD_ENTRY event?
> Does this supply the functionality you need? It would be easier to
> write a JVM TI agent  to collect this information than it would
> be to modify the interpreter.
> If you still want to modify the JVM code, read over
> jvmtiExport.cpp. Look for
> void JvmtiExport::post_method_entry()
> If you still want to modify the JVM, look over the code base for
> calls to post_method_entry() and that should give you an idea where
> to start.
> Hope this helps - Tim Bell
>  The JVM Tool Interface (JVM TI): How VM Agents Work
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