Weldon Washburn wrote:
On 9/26/06, Leo Li <[EMAIL PROTECTED]> wrote:
Hi, Weldon:
The usage of the argument of portLibrary is for the function to call
other functions of the port library if needed. The argument is just a
virtual function table, as you said, can be any implemenatation of the
HyPortLibrary struct, not only the HyPortLibrary struct the function
belongs
to. Of course, different HyPortLibrary might lead to different
behavior of
the function if the HyPortLibrary is used by it.
I think the main purpose of the design is to alter some function
of a
specified HyPortLibrary struct flexibly, especially at runtime: What is
necessary to do is just to change an entry in HyPortLibrary while the
altered function can make use of other functions as well as other
functions
can use it.
Am I all right?:)
Hmmm... Interesting idea you have. Basically the idea is to rewrite the
virtual function table _before_ any of the functions are used. This
makes
much more sense than the way drlvm currently boots up. By the way, is
there
any documentation that says what you are suggesting? In other words, was
portlib specifically designed to do what you suggest?
I think so, here below the part of portlib document at {harmony svn
root}/enhanced/classlib/trunk/doc/vm_doc/html/group__Port.html
"The port library is implemented as a table of function pointers. One
advantage of a function pointer based table is the ability to replace
any functionality without recompiling the entire Java virtual machine.
For example if an application is experiencing a memory leak, the memory
management functions of the port library can be replaced to help
determine the root cause of this leak. Alternatively applications
wishing to control all memory allocation can provide their own routines
to override the platform specific allocation and deallocation of memory.
Various implementations of the port library may choose not to implement
all functionality contained in the port library table. If a platform
does not support sockets, and thus the Java virtual machine does not
utilize sockets, the port library does not need to provide a valid
socket behavior. The port library contains version control information
<cid:[email protected]> that enables applications to
determine if required functionality is supported. In addition the
version control information allows applications to determine if the port
library provided is compatible with the one which they were compiled
against."
On 9/25/06, Weldon Washburn <[EMAIL PROTECTED]> wrote:
>
> It looks like hysignal.c is using the right monitor enter/exit().
That
> is,
> the one
> from drlvm/trunk/build/win_ia32_msvc_debug/deploy/jre/bin/hythr.dll
>
> However, a bunch of functions in classlib's hysignal.c have an
incoming
> argument of "HyPortLibrary *portlib". The portlib variable can either
> point
> to the original classlib portlib C struct. Or it can point to PORTLIB
> which
> is a C struct with all the entries nulled out (more on this later.)
>
> I think the next question to ask is what hysignal.c does with
> the "HyPortLibrary *portlib" argument. If anyone knows, please
tell us.
> Otherwise I will keep digging.
>
> From stepping through DRLVM bootup, it looks like classlib's
portlib is
> _dropped_ in signalProtectMain(). Then launcher gpProtectedMain
calls
> invocation(PORTLIB,...) where PORTLIB is a nulled out HyPortLibrary C
> struct. We need to put comments in the code describing the switch
from
> classlib's portlib to drlvm's nulled out version.
>
> On 9/22/06, Weldon Washburn <[EMAIL PROTECTED]> wrote:
> >
> > All,
> > Its not clear at this moment what threading implementation is being
> > executed when hysignal.c calls hythread_monitor_enter(). If someone
> > already knows, please tell us. Otherwise, I will step through it
with
> the
> > debugger to find out what is going on.
> > - Weldon
> >
> > --
> > Weldon Washburn
> > Intel Middleware Products Division
> >
>
>
>
> --
> Weldon Washburn
> Intel Middleware Products Division
>
>
--
Leo Li
China Software Development Lab, IBM
--
Paulex Yang
China Software Development Lab
IBM
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