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To: Lin Yo-An <cornelius.howl@gmail.com>
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	Nikita Popov <nikic@php.net>
Thread-Topic: [PHP-DEV] Object getter method optimization
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Date: Tue, 22 Mar 2016 08:45:34 +0000
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Subject: Re: [PHP-DEV] Object getter method optimization
From: dmitry@zend.com (Dmitry Stogov)

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Hi Yo-An Lin,


This "run-time inlining" approach may work.


PHP compiler (or optimizer) may mark functions and methods suitable for "ru=
n-time" inlining (e.g. methods without arguments and FETCH_OBJ_R UNUSED, CO=
NST -> TMP; RETURN TMP).

Then INIT_METHOD_CALL may check this flag and execute "optimized code seque=
nce" instead of pushing stack frame and real call.


However, I'm not sure what kind of performance impact this may make, becaus=
e we will have to make additional check on each INIT_METHOD_CALL execution.


Thanks. Dmitry.


________________________________
From: Lin Yo-An <cornelius.howl@gmail.com>
Sent: Saturday, March 19, 2016 10:08
To: Dmitry Stogov
Cc: internals; Xinchen Hui
Subject: Re: [PHP-DEV] Object getter method optimization

Hi Dmitry,


Thanks for your reply! You're correct. let me try to explain your points:

If I have a main.php and worker.php

And I defined work($worker) { $status =3D $worker->getStatus(); } inside ma=
in.php

when main.php is compiled, we don't know what the class entry of $worker is=
. What we only know is invoking a method "getStatus" on $worker CV unless w=
e know we have to compile worker.php before main.php and add a type hint on=
 $worker.

Is it correct?


Since the original approach doesn't work, here comes another new idea:

When executing method call on an object, if we found the method body are ju=
st 2 op codes (FETCH_OBJ_R and RETURN), we then denote the method is a "get=
ter method"

And the next time, when we execute the same method, we found the "getter me=
thod" flag, we simply execute FETCH_OBJ_R on that object and return the val=
ue to avoid extra op code execution time.

Do you think if this could work?




Best Regards and Thanks for your work on PHP VM
Yo-An Lin































On Fri, Mar 18, 2016 at 3:36 PM, Dmitry Stogov <dmitry@zend.com<mailto:dmit=
ry@zend.com>> wrote:
Hi Yo-An Lin,

Unfortunately, this approach won't work.
At first, at compile time we don't know the body of called getter.
At second, the called method might be changed even at run-time, because of =
polymorphism.

Tricks like this might be implemented using JIT and polymorphic inline cach=
es.

Thanks. Dmitry.

________________________________________
From: Lin Yo-An <cornelius.howl@gmail.com<mailto:cornelius.howl@gmail.com>>
Sent: Friday, March 18, 2016 05:23
To: internals
Subject: [PHP-DEV] Object getter method optimization

Hello Everyone,


I am recently trying to write an optimizer that could optimize the getter
method call into just one object fetch opcode.

I'd like to know thoughts from you guys, here is the note:
https://c9s.hackpad.com/INLINE-OP-TVGo9WcshbZ

--
Best Regards,

Yo-An Lin
https://github.com/c9s



--
Best Regards,

Yo-An Lin

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