[Vm-dev] VM Maker: VMMaker.oscog-eem.363.mcz

[David T. Lewis]

On Wed, Sep 11, 2013 at 07:55:14AM -0700, Eliot Miranda wrote:
>  
> On Tue, Sep 10, 2013 at 4:14 PM, David T. Lewis <lewis at mail.msen.com> wrote:
> 
> >
> > On Tue, Sep 10, 2013 at 09:50:14PM +0000, commits at source.squeak.org wrote:
> > >
> > > Eliminate bytesPerWord in favour of wordSize (Smalltalk wordSize is
> > > the model here).  wordSize is shorter.  However, still generate
> > > BytesPerWord for wordSize since e.g. mpegtype.h has a parameter
> > > named WordSize.
> > >
> >
> > FYI a number of constants including BytesPerWord and BaseHeaderSize
> > are replaced by message sends in VMM trunk as part of the changes
> > that put this all under compile time control (as opposed to defining
> > at code generation time). It would probably be good to apply these
> > changes to oscog at some point also, although I cannot realistically
> > offer to put any time into it right now.
> >
> 
> Agreed.  I was reluctant to do this earlier.  Alas while it might allow one
> to run e.g. a 64-bit ObjectMemory alongside a 32bit ObjectMemory, the
> pervasive use of class and pool variables means its not possible to run an
> ObjectMemory against a SpurMemoryManager.  I'd rather change the code base
> as little as possible than risk breaking things, so I'm happy to live with
> e.g. the compact class indices staying in class/pool vars.
> 
> BTW, David, I implemented
> NewObjectMemory>>eeInstantiateClassIndex:format:numSlots: (in
> VMMaker.oscog-eem.369) which needs to set the Size4Bit.  It contains a
> comment asking you to check the code :-).  I wonder if, in your copious
> free time, you might do just that?  No hurry, and indeed I hope to render
> ObjectMemory and NewObjectMemory obsolete asap :-).

I will look at it this weekend. There is another thing that I did in trunk
that might be relevant - I refactored ObjectMemory so that it has separate
NewObjectMemory and ClassicObjectMemory, and no method overrides. The intent
is to get a clear separation of the (limited) actual differences between
the two. I think this is consistent with your original design intent, so
I was trying to do some follow up work in that regard. If you have a chance,
please try loading http://source.squeak.org/VMMaker/update-dtl.13.mcm
into a clean image and let me know if the class hierarchy for the object
memory and interpreter make sense to you.

I definitely don't think we should try to do any updates of these things 
while you are in the middle of the Spur work (and I would not have time
to work on in now anyway), but it would be good to know if they make sense
directionally.

Dave