Re: Issues with exceptions and overloading opcodes

On Tue, 20 Oct 2015, Bob Weinand wrote: > > Am 20.10.2015 um 17:11 schrieb Xinchen Hui <laruence@php.net>: > > > > On Tue, Oct 20, 2015 at 10:45 PM, Derick Rethans <derick@php.net > > <mailto:derick@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.phpې|�s; > >> gz�։0� > >> ) 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