Common Smalltalk VM Summit

J J azreal1977 at
Fri Oct 6 20:27:18 UTC 2006

>From: "David Griswold" <David.Griswold at>
>Reply-To: The general-purpose Squeak developers 
>list<squeak-dev at>
>To: "The general-purpose Squeak developers 
>list"<squeak-dev at>
>Subject: RE: Common Smalltalk VM Summit
>Date: Fri, 6 Oct 2006 11:18:27 -0700
>A lot of this confusion isn't your fault, it's the fault of the unfortunate
>choice of term "type-feedback," which is historical.  It is really "class"
>or "implementation type" feedback, and it is a mechanism *inside* the
>Strongtalk VM that dynamically tracks what instance classes occur at each
>send site, to learn how to inline and optimize those sends.
>The Strongtalk "type system" is a *completely* unrelated subsystem, that
>runs outside the VM in Smalltalk.  Strongtalk types are not implementation
>or class types, but pure interface types, that have nothing to do with
>classes, so they are not useful for optimization.  They are used purely to
>check the code and make it more structured and understandable, and are 
>on static analysis, not dynamic analysis.
>So Strongtalk has two, unrelated features: a dynamic type(class)-feedback
>VM, and a Smalltalk static type(interface)-checker.

Thank you very much for the explaination.  This thread sounds a lot more 
interesting now. :)

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