Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:49082
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.215.170 as permitted sender)
DomainKey-Status: bad
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:in-reply-to:references:date:message-id:subject:from:to
         :cc:content-type;
        b=MbTwcN/vcQNjEtkMKaPF9AAGFWClKBigMsnn+BUMyB4tuX4h2loU1/+d4fWqLLrmm9
         5mIzTZ4YAKrhoEs5WF+5Ky7twuRmPsiJXs4ptjbqIPNoVusJhrM8P2xXDQ/L8ub4hjKY
         NWnEWF8QR58LYzxW9hM7kleH+LBaBxgs8Y+4o=
MIME-Version: 1.0
In-Reply-To: <4C3ED076.5060605@zend.com>
References: <4C3ED076.5060605@zend.com>
Date: Thu, 15 Jul 2010 19:18:34 -0300
Message-ID: <AANLkTim-4JQVruNmbBNqaMiXBw8IQ5wwLQ0FRJI_aCjJ@mail.gmail.com>
To: Dmitry Stogov <dmitry@zend.com>
Cc: PHP Internals <internals@lists.php.net>, Zeev Suraski <zeev@zend.com>
Content-Type: multipart/alternative; boundary=0015174c437cafd04b048b747bf1
Subject: Re: [PHP-DEV] [PATCH] string_offset access optimization
From: felipensp@gmail.com (Felipe Pena)

--0015174c437cafd04b048b747bf1
Content-Type: text/plain; charset=UTF-8

Hi Dmitry,

2010/7/15 Dmitry Stogov <dmitry@zend.com>

> Hi,
>
> Recently I noticed that reading of string offset is performed in two steps.
> At first special string_offset variant of temporary_variable is created in
> zend_fetch_dimension_address_read() and then the real string value is
> created in _get_zval_ptr_var_string_offset().
>
> I think we can create the real string in the first place. This makes 50%
> speed-up on string offset reading operation and allows to eliminate some
> checks and conditional brunches in VM.
>
> The patch is attached (don't forget to regenerate zend_vm_execute.h to test
> it). However it changes behavior in one bogus case.
> The following code now will emit "b" (currently it generates a fatal error
> - cannot use string offset as an array).
>
> $str = "abs";
> var_dumo($str[1][0]);
>
> I think it's not a problem at all.
> "b" makes sense because "abs"[1] -> "b" and "b"[0] -> "b".
>
> I'm going to commit the patch in case of no objections.
>
> Thanks. Dmitry.
>


> The patch looks good, I did some tests, not found anything strange.
Good simplyfication! :)

-- 
Regards,
Felipe Pena

--0015174c437cafd04b048b747bf1--