Review Request: Zero JSR 292 support

[Gary Benson]

Christian Thalinger wrote:
> On Apr 4, 2011, at 10:34 AM, Gary Benson wrote:
> > John Rose wrote:
> > > On Apr 1, 2011, at 7:33 AM, Gary Benson wrote:
> > > > This webrev adds support for JSR 292 to Zero:
> > > > 
> > > > http://cr.openjdk.java.net/~gbenson/zero-jsr292-01/
> > > 
> > > Most impressive!  I think this matches the following previously
> > > filed bug:
> > > 
> > > 6829195  JSR 292 needs to support the C++ interpreter
> > 
> > Partially, yes, in that it implements invokedynamic and fast_aldc*
> > in the bytecode interpreter.  For the sparc or x86 ports you would
> > also need to write the method handle entries and add frame manager
> > support for the call_method_handle message.
> 
> How much work would that be?

I'm not sure.  Actually, thinking about it, the method handle entries
are already there (the template and C++ interpreters have the same
ABI, no?)  You could check by trying to run the method handles tests.
If that's the case, the only extra bit is adding support for
call_method_handle.  There's a potential trap, however, in that the
calls to InterpreterRuntime::resolve_invokedynamic and
InterpreterRuntime::resolve_ldc from BytecodeInterpreter::run enter VM
mode and end up reentering the C++ interpreter.  I don't know that the
assembly language ports can handle this.  They're certainly written to
avoid it, but that might be simply because BytecodeInterpreter::run
has a huge stack frame and they didn't want too many of those on the
stack.  If it is a problem I have some partially written code that
would work around this but once I realised Zero didn't need it I
stopped working on it.

Cheers,
Gary

-- 
http://gbenson.net/