RE: [PHP-DEV] RFC: mark functions as const for possible optimizations

Hi, Just a thought, now dl() has been deprecated and disabled in SAPIs (except CLI,CGI,embed), would that mean extension_loaded() would become a optimizable function? So something like include extension_loaded('gmp') ? 'GMPFoo.php' : 'PHPFoo.php'; Would be optimized to be more APC friendly? Jared > -----Original Message----- > From: Nuno Lopes [mailto:nlopess@php.net] > Sent: 14 September 2007 18:01 > To: PHPdev > Cc: stas@zend.com; andi@php.net; dmitry@php.net > Subject: [PHP-DEV] RFC: mark functions as const for possible > optimizations > > Hi, > > Following my last post on bytecode optimization > (http://news.php.net/php.internals/32113), I would like to > discuss a few more things. > The patch in that e-mail allowed the engine itself to do > transformations like, e.g.: > $a = 1*2*3*4*5+1-0; --> $a = 121; > > However the patch is now a bit dead because Stas would like > to have more advanced things that I didn't have time yet to > look at (because the proposal introduces several difficult > ambiguities in the grammar). > > So, let's move on for now :P > > My proposal is the following: > some functions when fed with constant arguments always return > a constant value, too. e.g.: > strlen('abcd') === 4. > > This means that an optimizer can and should do this > transformation. (and others like: $a='abcd'; strlen($a); -> > 4). I think Ilia created a list of such functions in his > optimizer. But I would like to have that list in the core, so > that everybody can benefit from it. > Basically the only thing needed to do is to change PHP_FE() to > PHP_CONST_FE() in the function entry tables. > > The patch: > http://web.ist.utl.pt/nuno.lopes/zend_const_function_entry.txt > (includes a few function entries changed as an example) > > > Nuno > > P.S.: the university semester has already started, so don't > worry with the > e-mail traffic I'm generating because it'll end pretty soon > (until the next > vacations :P) > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php >