Embed ciMethod's methodOop into CodeBuffer?

[Tom Rodriguez]

You can safely embed perm oops in nmethods but not regular  
CodeBuffers.  During code generation you use methods in the  
MacroAssembler to embed references to a JNI handle in the code, along  
with relocation information to describe it.  When the compilation  
CodeBuffer is converted into an nmethod, the jobject is dereferenced  
and that object is placed into the code stream.  This dance is  
required partly because the compiler is running in native mode, so it  
has to use JNI for GC safety.  On intel look at movoop and the  
associated code for that, along with oop_Relocation in relocInfo.hpp  
and OopRecorder in oopRecorder.hpp.  I'm not sure how well our  
strategy is going to work for Zero since it requires the ability to  
patch the instruction stream after a GC to update any oops which have  
moved.  Are you able to support that?

tom

On Jun 2, 2009, at 5:10 AM, Gary Benson wrote:

> Hi all,
>
> I've been looking at the method call stuff in Shark, and I figure
> there's a whole bunch of optimizations I can perform if I can embed
> the methodOop corresponding to a given ciMethod into the CodeBuffer.
> Is this possible?
>
> Cheers,
> Gary
>
> -- 
> http://gbenson.net/