> Am 20.10.2015 um 18:08 schrieb Derick Rethans <der...@php.net>:
> 
> On Tue, 20 Oct 2015, Bob Weinand wrote:
> 
>>> Am 20.10.2015 um 17:11 schrieb Xinchen Hui <larue...@php.net>:
>>> 
>>> On Tue, Oct 20, 2015 at 10:45 PM, Derick Rethans <der...@php.net 
>>> <mailto:der...@php.net>> wrote:
>>> 
>>>> 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/master/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.
>>>> 
>>>> Would you care to have a look?
>>>> 
>>> 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>
>>> 
>>> 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?
>> 
>> 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 == 
>> 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… why don't you always exempt 
>> it?
> 
> Even if I do (like I've just pushed into the extension), the test still 
> fails because the code loops. So you did break something.
> 
> cheers,
> Derick
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Ah, ZEND_CATCH indeed also allows EG(exception) to be non-null…

… maybe I should write

if (EG(exception)
 && opline->opcode != ZEND_HANDLE_EXCEPTION && opline->opcode != ZEND_CATCH
 && ret != ZEND_USER_OPCODE_DISPATCH && ret != ZEND_USER_OPCODE_RETURN && ret 
!= ZEND_USER_OPCODE_ENTER && ret != ZEND_USER_OPCODE_LEAVE) {
    HANDLE_EXCEPTION();
}

to allow dispatching for these two opcodes too?

Bob
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