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Date: Fri, 1 Apr 2016 16:35:59 +0800
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To: Dmitry Stogov <dmitry@zend.com>
Cc: internals <internals@lists.php.net>, Xinchen Hui <laruence@php.net>, 
	Nikita Popov <nikic@php.net>
Content-Type: multipart/alternative; boundary=001a113e4d62bbbe5d052f6844fd
Subject: Re: [PHP-DEV] Object getter method optimization
From: cornelius.howl@gmail.com (Lin Yo-An)

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Hi Dmitry, Nikita, Andrea


My implementation now is able to get the property offset and fetch object
property directly without invoking zend_std_read_property and pushing new
call frame onto the stack.

The current behavior:

1. In compile-time, the pass_two() function now marks the getter functions
in op_array.accessor.type

2. When Zend Engine first time attempt to read the property, it saves the
property offset in the accessor field and mark the method as a "getter".

3. When Zend Engine second time invoke the getter method, it checks the
accessor field and try to read the property value directly instead a
"method call"



The implementation did some change:

1. Added accessor struct to op_array to save "accessor" related information
(getter or setter, property offset)

2. Added two statement in zend_std_read_property to save property offset.

3. Added op code check in zend_compile (The pass_two() function) to mark a
function is a getter)


But now I encountered a problem, I can't store the result value in
INIT_METHOD_CALL op, the result var is only available in DO_FCALL_*



I have an idea for solving this, but I'm not sure if it's good or not:


If DO_FCALL_* will always follow a INIT_METHOD_CALL, then I think we can
store result var from the next op (DO_FCALL) and skip DO_FCALL directly.


Would be great if I can have your advices and suggestion. :-)


Thanks, Yo-An Lin


















On Tue, Mar 22, 2016 at 4:45 PM, Dmitry Stogov <dmitry@zend.com> wrote:

> Hi Yo-An Lin,
>
>
> This "run-time inlining" approach may work.
>
>
> PHP compiler (or optimizer) may mark functions and methods suitable for
> "run-time" inlining (e.g. methods without arguments and FETCH_OBJ_R UNUSED,
> CONST -> TMP; RETURN TMP).
>
> Then INIT_METHOD_CALL may check this flag and execute "optimized code
> sequence" instead of pushing stack frame and real call.
>
>
> However, I'm not sure what kind of performance impact this may make,
> because 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 = $worker->getStatus(); } inside
> main.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
> we 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
> just 2 op codes (FETCH_OBJ_R and RETURN), we then denote the method is a
> "getter method"
>
> And the next time, when we execute the same method, we found the "getter
> method" flag, we simply execute FETCH_OBJ_R on that object and return the
> value 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
>
>
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> On Fri, Mar 18, 2016 at 3:36 PM, Dmitry Stogov <dmitry@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
>> caches.
>>
>> Thanks. Dmitry.
>>
>> ________________________________________
>> From: Lin Yo-An <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
>



-- 
Best Regards,

Yo-An Lin

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