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Date: Tue, 20 Oct 2015 17:53:37 +0200
CC: Dmitry Stogov <dmitry@zend.com>,
 PHP Developers Mailing List <internals@lists.php.net>
References: <alpine.DEB.2.20.1510201531060.10651@whisky.home.derickrethans.nl> <CABBJUpeTDADC+hp+W--j0=WTcpV4o3HCw+fOoZjZhnj3oB3eGg@mail.gmail.com>
To: Xinchen Hui <laruence@php.net>,
 Derick Rethans <derick@php.net>
Subject: Re: [PHP-DEV] Issues with exceptions and overloading opcodes
From: bobwei9@hotmail.com (Bob Weinand)

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> Am 20.10.2015 um 17:11 schrieb Xinchen Hui <laruence@php.net>:
>=20
> Hey:
>=20
>=20
>=20
> On Tue, Oct 20, 2015 at 10:45 PM, Derick Rethans <derick@php.net =
<mailto:derick@php.net>> wrote:
>=20
>> Hi!
>>=20
>> When hacking on Xdebug for PHP 7, I ran into some issues where PHP =
would
>> just spin around. This happens when there is an exception, and I use
>> overloaded opcodes. I wrote a small example extension at
>> https://github.com/derickr/php-minimal-opcode-overloading-example =
with a
>> test case
>> (
>> =
https://github.com/derickr/php-minimal-opcode-overloading-example/blob/mas=
ter/tests/test.php
>> )
>> that shows that something is looping in executing opcodes, as the
>> HANDLE_EXCEPTION iirc doesn't advance to the next opline. I believe =
this
>> is a recent enough change, as it only started happening after I =
upgraded
>> from about RC1 to latest master.
>>=20
>> Would you care to have a look?
>>=20
> This is introduced by a fix made by Bob,
> https://github.com/php/php-src/commit/808f62bb =
<https://github.com/php/php-src/commit/808f62bb>
>=20
> Bob, I am going to revert this for now, since you didn't include a =
test
> script to show where the problem was,  I am not sure why you made =
this?
>=20
>=20
> thanks
>=20
>>=20
>> cheers,
>> Derick
>>=20
>> --
>> http://derickrethans.nl <http://derickrethans.nl/> | =
http://xdebug.org <http://xdebug.org/>
>> Like Xdebug? Consider a donation: http://xdebug.org/donate.php =
<http://xdebug.org/donate.php>
>> twitter: @derickr and @xdebug
>> Posted with an email client that doesn't mangle email: alpine
>>=20
>=20
>=20
>=20
> --=20
> Xinchen Hui
> @Laruence
> http://www.laruence.com/ <http://www.laruence.com/>
I didn't add any test case as we don't have any APIs in php-src using =
that user_opcode handler.
I discussed the change back then with Dmitry and committed with his =
review.

It concretely broke uopz which might throw an exception itself. And in =
turn we realized that for integrity we need to ensure that opline =3D=3D =
EX(opline) else we'll end up with different behavior in global register =
builds and normal builds.

In general, you should not overload ZEND_HANDLE_EXCEPTION (if you need =
to, have a special handling for it, but never directly dispatch to it). =
It is quite special being the only opcode actually allowing =
EG(exception) to be non-NULL at the start of it.

You are doing an #ifdef ZTS to exempt it=E2=80=A6 why don't you always =
exempt it?

Bob=

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