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From "Alexey Varlamov" <alexey.v.varla...@gmail.com>
Subject Re: [drlvm] [jvmti] Question about JVMTI calling Java code
Date Thu, 14 Sep 2006 05:15:16 GMT
14.09.06, Gregory Shimansky<gshimansky@gmail.com> написал(а):
> On Wednesday 13 September 2006 16:14 Weldon Washburn wrote:
> > Gregory,
> >
> > You might want to look closely at the code paths in the JVMTI functions.
> > If the functions in question happen to be arbitrary Java code, then these
> > code paths could lead to many other parts of the JVM which in turn might be
> > written in Java.  In the future the JIT runtime helpers or the GC may be
> > written in Java.  For example, an innocent looking object new, poll for GC
> > or poll for preemption inside a JVMTI function could take the execution
> > path deep inside of MMTk, or as mentioned below, deep inside
> > java.util.concurrent .
> >
> > Rather than develop a general solution at this point, it may make sense to
> > make all the data JVMTI needs to read/write accessible from C code.
>
> This is what I am trying to determine. Just how much of the data currently
> _cannot_ be taken from the native code. I am quite sure thread manager can
> provide a thread name or its priority.
>
> A more problematic data in my view may be something like
> Thread.getContextClassLoader(). Since it is not directly needed for threading
> model it isn't probably kept in any native structures. Getting it may be done
> through direct access to the field of j/l/Thread. It is a kernel class of
> course, but this will oblige a classlib implementation for Harmony to have
> the same field name.
I definitely miss smth here. The kernel class by definition is VM
specific, the same as JVMTI implementation, what classlib
implementation do you mean and what obligations?
I believe we can get any of the attributes you listed via direct field
access without imposing any dependencies (outside the VM).
--
Alexey

> --
> Gregory Shimansky, Intel Middleware Products Division
>
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