Guilherme Ottoni
97e2eac6a7
This diff significantly generalizes guard relaxation and adds support for more bytecode instructions. Before, only CGetL, SetL, RetC, and RetV were able to relax their inputs, and only in limited ways, e.g. if their outputs were not used or only used in specific ways. The new approach follows how the input types flow into the output types, thus allowing dependencies to be relaxed even if they feed a chain of values through the tracelet. This diff also add support for relaxing inputs for the following bytecode instructions: - Pop* - FCall - FCallArray - AddElemC - ArrayIdx - SetS - SetG - ContPack - ContRetC - ContHandle The spill area was also increased (from 16 to 32 cells) since relaxed dependencies increase register pressure -- relaxed types are not immediates that can be burned in and need to reside in registers instead.
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.