mwilliams
795aa1309c
For PhpFiles, there was a mixed management system, where references from translated code were held until the code was made unreachable, while references from interpreted code were held for the duration of the current request. Under the new scheme, PhpFiles are always treadmilled. They are owned by the FileRepository, and so need to be ref-counted because the FileRepository can have the same PhpFile under multiple paths. But we don't ref-count the *uses* of PhpFiles anymore. Classes still need to be ref-counted, but as soon as their Unit goes away, most of their internals can be freed. We just need to hold onto them if derived classes are referencing them. Even in that case, the next time we try to instantiate the derived class, we can kill any that reference this Class. There were also lots of holes where references were not dropped, or owned data structures were not destroyed. eg a Class's methods were not destroyed when the Class was destroyed; there were several paths where an entry was erased from the file map, but the corresponding PhpFile was not decRef'd - or worse, a null entry was left in the map (something we had asserts to check for). This tries to make the handling more consistent.
HipHop VM for PHP 
HipHop VM (HHVM) is a new open-source virtual machine designed for executing programs written in PHP. HHVM uses a just-in-time compilation approach to achieve superior performance while maintaining the flexibility that PHP developers are accustomed to. HipHop VM (and before it HPHPc) has realized > 5x increase in throughput for Facebook compared with Zend PHP 5.2.
HipHop is most commonly run as a standalone server, replacing both Apache and modphp.
Installing
You can install a prebuilt package or compile from source.
Running
You can run standalone programs just by passing them to hhvm: hhvm my_script.php.
HipHop bundles in a webserver. So if you want to run on port 80 in the current directory:
sudo hhvm -m server
For anything more complicated, you'll want to make a config.hdf and run sudo hhvm -m server -c config.hdf.
Contributing
We'd love to have your help in making HipHop better. If you run into problems, please open an issue, or better yet, fork us and send a pull request. Join us on #hhvm on freenode.
If you want to help but don't know where to start, try fixing some of the Zend tests that don't pass. You can run them with hphp/test/run. When they work, move them to zend/good and send a pull request.
Before changes can be accepted a Contributors Licensing Agreement (pdf - print, sign, scan, link) must be signed.
Licence
HipHop VM is licensed under the PHP and Zend licenses except as otherwise noted.