[webkit-dev] Functionality of create_activation and tear_off_activation

Abhishek Bichhawat abhishek_bichhawat at yahoo.co.in
Thu Jun 20 00:26:09 PDT 2013

Thanks Geoffrey.
I was also interested in knowing, how these opcodes work with the scopechain, i.e., 
how many nodes does it push into the scopechain and how does it determine how many nodes to "skip" in get_scoped_var with multiple nested functions.

Thanks and Regards,

 From: Geoffrey Garen <ggaren at apple.com>
To: Abhishek Bichhawat <abhishek_bichhawat at yahoo.co.in> 
Cc: "webkit-dev at lists.webkit.org" <webkit-dev at lists.webkit.org> 
Sent: Wednesday, 19 June 2013 6:53 PM
Subject: Re: [webkit-dev] Functionality of create_activation and tear_off_activation

op_create_activation creates a closure.

op_tear_off_activation copies stack variables into the heap in order to persist the closure after the function returns.

For more information about closures, see http://en.wikipedia.org/wiki/Closure_(computer_science).


On Jun 18, 2013, at 12:38 PM, Abhishek Bichhawat <abhishek_bichhawat at yahoo.co.in> wrote:

>We are working on a research project involving webkit. We are currently using Webkit-r122160 and trying to understand the functionality of two of the opcodes (op_create_activation and op_tear_off_activation), which are a part of the classical interpreter. Although, the classical interpreter has been phased out, we would appreciate if you could provide an insight into the functionality of the two opcodes. We are interested in the low-level details of the opcodes as to how they insert an object in the heap/register/scopechain and delete it from there. 
>Thanks and Regards,
>webkit-dev mailing list
>webkit-dev at lists.webkit.org
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