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To: Marcus Boerger <helly@php.net>
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Subject: Re: [PHP-DEV] Method call improvements
From: dmitry@zend.com (Dmitry Stogov)


Marcus Boerger wrote:

> Aren't we able to bind these at least partially to the function call
> opcode, in case we know they are constant? If all is constsnt we could
> even store the whole lookup in the opcode. Well you'd have to convince
> Zend to do that because os far they have always been against this
> approach.

We can't modify opcode it self as it'll break opcode caches.

However we can introduce some indirect table associated with op_array, 
which can be used to implement inline caches without direct opcode 
modification (in the same way as IS_CV variables work). There are a lot 
of papers about polymorphic inline caches (e.g. 
http://research.sun.com/self/papers/pics.html) which we probably should 
use to not to invite bicycle.

Thanks. Dmitry.