Hi, I'm working on a PoC, implementing the proposed behavior - https://gist.github.com/dstogov/a311e8b0b2cabee4dab4
Only few PHPT tests had to be changed to confirm new behavior and actually they started to behave as HHVM. 2 tests are still unfixed XFAILed. Foreach by reference is still need to be improved to support different array modifications. The patch makes ~1% improvement on Wordpress-3.6 (saving duplication and destruction of 200 arrays on each request) Thanks. Dmitry. On Thu, Jan 22, 2015 at 1:38 PM, Benjamin Coutu <ben.co...@zeyos.com> wrote: > Hi Nikita, > > I would suggest using the proposal for the by-value case and sticking with > the current behavior for the by-reference case as you suggested. Granted, > we then cannot remove the internal pointer all together, but we would just > use it for the less common by-reference case as well as for the legacy > reset/next functions, of course. This would still improve most for-each > traversals. At least we then wouldn't have to find a replacement solution > for rest/prev/next/end. Moreover we can then move the internal position > pointer out of the hashtable structure into zend_array because it is only > used for userland arrays, not other hash tables (such as object properties > or internal structures that build upon the hashtable struct). > > Thanks, > > Ben > > ========== Original ========== > From: Nikita Popov <nikita....@gmail.com> > To: Benjamin Coutu <ben.co...@zeyos.com> > Date: Thu, 22 Jan 2015 10:53:19 +0100 > Subject: Re: [PHP-DEV] Improvements to for-each implementation > > Doing this was the idea I had in mind as well, i.e. change the semantics of > foreach to say that it will always work on a copy for by-value iteration > (which ironically avoids having to actually copy it). Note that this will > differ from the current behavior in a number of ways. In particular it > means that changes to arrays that were references prior to iteration will > not influence the iteration. > > The real question is what we should do in the by-reference case. Given that > we need to acquire references to elements of the original array we can't > reasonably work with copy-semantics (at least I don't see how). So would we > just stick with the previous behavior (using the hash position hack) for > that? > > Nikita > > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > >
