Andrei Alexandrescu
a2e76eb7b2
The codebase had several namespace-level static data definitions and function definitions. Using namespace-level "static" in a .h file is near-always a bad idea, as follows: - for simple types, static is implied. Example: "const int x = 42;" is the same as "static const int x = 42;" - for aggregate types, static linkage implies that a copy of the aggregate will appear in every compilation unit that includes the header. - for functions, static means the function will have a separate body generated in each compilation unit including the header. - in several places functions were defined 'static inline', which is just as bad. 'inline' is just a hint which means the function may end up having a body (and actually more due to 'static'). True, gnu's linker has means to remove duplicate definition, but that's not always guaranteed or possible (think e.g. static functions that define static data inside, ouch). So static is useless at best and pernicious at worst. We should never, ever use static at namespace level in headers. I will create a bootcamp task for a lint rule. I expected the performance to be neutral after the change, but in fact there's a significant drop in instruction count and therefore a measurable reduction in CPU time: https://our.intern.facebook.com/intern/perflab/details.php?eq_id=431903
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.