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Date: Mon, 24 Nov 2014 18:56:36 +0400
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To: Nikita Popov <nikita.ppv@gmail.com>
Cc: Xinchen Hui <xinchen.h@zend.com>, Anatol Belski <ab@php.net>, 
	PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=047d7b33db6a46f0fd05089c005a
Subject: Re: Use zend_string* for op_array->arg_info[].name and class_name
From: dmitry@zend.com (Dmitry Stogov)

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Hi Nikita,

Thanks for review. I already thought about both approaches and failed as
well (the second also doesn't work with C++).
The proposed patch doesn't complicate engine a lot (may be only the
inheritance code), but I afraid about problems in some edge cases.

Thanks. Dmitry.

On Mon, Nov 24, 2014 at 5:27 PM, Nikita Popov <nikita.ppv@gmail.com> wrote:

> On Mon, Nov 17, 2014 at 10:25 AM, Dmitry Stogov <dmitry@zend.com> wrote:
>
>> Hi,
>>
>> Please review the patch
>> https://gist.github.com/dstogov/47a39aff37f0a6441ea0
>>
>> Thanks. Dmitry.
>>
>
> Hi Dmitry, sorry for late reply.
>
> The problem we're trying to solve here is lack of ability to create a
> zend_string at compile time. I just tried two ideas how we might be able to
> do that, to avoid introducing different arginfos for internal/userland
> functions.
>
> My first approach was to create a zend_string as a string literal using
> (zend_string *) ("\1\0\0\0" "\6\1\0\0" "\0\0\0\0" "\0\0\0\0" str) (for
> 32bit LE) and then update the length in zend_register_functions. However
> this didn't work because the string literal ends up in readonly
> memprotected memory, so this causes a segfault.
>
> My second approach was to use a C99 compound literal to create a temporary
> zend_string-like structure with the correct length:
>
> #define ZEND_STRING_CT(str) \
>     (zend_string *) (struct { \
>         uint32_t refcount; uint32_t type_info; \
>         zend_ulong h; size_t len; \
>         char val[sizeof(str)]; \
>     }[1]) {{ 1, IS_STRING | (IS_STR_PERSISTENT << 8), 0, sizeof(str)-1,
> str }}
>
> This seems to work fine (patch
> https://github.com/nikic/php-src/commit/5d49321cd9728e0cc1c2939432e46159f9a78472).
> However it requires C99, which we're currently not allowed to use.
>
> Maybe someone has an idea how this can be done in C89?
>
> Nikita
>

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