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Behavior class variable 'IndirectInstVars'

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Richard Sargent

Behavior class variable 'IndirectInstVars'

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I came across this class variable. I was wondering what it was all about.
Is there anyone at Instantiations who knows and wants to tell? :-)

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Seth Berman

Re: Behavior class variable 'IndirectInstVars'

Hi Richard,

I wanted to get you an answer...thought I'm not sure its the best one because I haven't been in this area a whole lot.

It looks like IndirectInstVars comes into play when packaging an image. I guess with IC read-only segments and the fact that a runtime can have multiple ICs, there is a problem to solve involving objects referring to each other across boundaries. This IndirectInstVars seems to provide a central registry where these can be accessed and during packaging I see that bytecodes are rewritten such that the slots read/store indexes into this table which then get the actual value.

Looking at packager code makes my eyes bleed and puts me in a bad mood...so I had to stop:) Just consider this a best guess for the moment.

-- Seth

On Friday, November 21, 2014 5:43:40 PM UTC-5, Richard Sargent wrote:

I came across this class variable. I was wondering what it was all about.
Is there anyone at Instantiations who knows and wants to tell? :-)

Richard Sargent

Re: Behavior class variable 'IndirectInstVars'

Administrator

On Tuesday, November 25, 2014 8:49:46 AM UTC-8, Seth Berman wrote:

I wanted to get you an answer...thought I'm not sure its the best one because I haven't been in this area a whole lot.

Thanks, Seth. It's appreciated.

It looks like IndirectInstVars comes into play when packaging an image. I guess with IC read-only segments and the fact that a runtime can have multiple ICs, there is a problem to solve involving objects referring to each other across boundaries. This IndirectInstVars seems to provide a central registry where these can be accessed and during packaging I see that bytecodes are rewritten such that the slots read/store indexes into this table which then get the actual value.

That does sound sensible.

Looking at packager code makes my eyes bleed and puts me in a bad mood...so I had to stop:) Just consider this a best guess for the moment.

I agree ... and sympathize.

Thanks again.

-- Seth

On Friday, November 21, 2014 5:43:40 PM UTC-5, Richard Sargent wrote:
I came across this class variable. I was wondering what it was all about.
Is there anyone at Instantiations who knows and wants to tell? :-)