RFR 8004128: NPG: remove stackwalking in Threads::gc_prologue and gc_epilogue code

[Coleen Phillimore]

Mikael,  Thank you for the code review.  Can someone from the compiler 
group review the mdx removal?
thanks,
Coleen

On 7/16/14, 4:20 AM, Mikael Gerdin wrote:
>
> On Tuesday 15 July 2014 16.25.01 Coleen Phillimore wrote:
>
> > I didn't make this change to interpreter_frame_bcp or mdp_addr() at the
>
> > end. The frame code is consistent in returning intptr_t for objects on
>
> > the frame and then casting them to the right types. I think this is 
> better.
>
> Ok.
>
> /Mikael
>
> >
>
> > Thanks,
>
> > Coleen
>
> >
>
> > On 7/15/14, 11:40 AM, Mikael Gerdin wrote:
>
> > > Hi Coleen,
>
> > >
>
> > > On Monday 14 July 2014 20.05.50 Coleen Phillimore wrote:
>
> > >> Summary: remove bcx and mdx handling. We no longer have to convert
>
> > >> bytecode pointers or method data pointers to indices for GC since
>
> > >> Metadata aren't moved.
>
> > >>
>
> > >> Tested with nsk.quick.testlist, jck tests, JPRT.
>
> > >>
>
> > >> Most of this is renaming bcx to bcp and mdx to mdp. The content 
> changes
>
> > >> are in frame.cpp. StefanK implemented 90% of these changes.
>
> > >>
>
> > >> open webrev at http://cr.openjdk.java.net/~coleenp/8004128/
>
> > >
>
> > > This isn't exactly my area of the code, but I'm happy that we got 
> around
>
> > > to
>
> > > this cleanup!
>
> > >
>
> > > I looked through the change and to my not-so-runtime-familiar eyes it
>
> > > seems
>
> > > good.
>
> > >
>
> > > One thought about the frame accessors
>
> > >
>
> > > 244 intptr_t* interpreter_frame_bcp_addr() const;
>
> > > 245 intptr_t* interpreter_frame_mdp_addr() const;
>
> > >
>
> > > Now that the contents of bcp and mdp in the frames are always 
> pointers,
>
> > > perhaps these accessors should be appropriately typed?
>
> > >
>
> > > Something like
>
> > >
>
> > > 244 address* interpreter_frame_bcp_addr() const;
>
> > > 245 ProfileData** interpreter_frame_mdp_addr() const;
>
> > >
>
> > > Also, BytecodeInterpreter still has a member named _mdx, should 
> that be
>
> > > renamed to _mdp as well?
>
> > >
>
> > > /Mikael
>
> > >
>
> > >> bug link https://bugs.openjdk.java.net/browse/JDK-8004128
>
> > >>
>
> > >> Thanks,
>
> > >> Coleen
>