Mike Magruder
609abd866f
We had a lot of odd behavior with both Next and Out. Previously the debugger would interpret the world until it saw that it was no longer on a specific line, or at a specific stack depth. I changed it recently to let the program run normally, and use an internal breakpoint to control step outs. Next's become like a step out temporarily when you descend into a function and need to get back out to the original line, so some bugs with out showed as bugs with Next, too. Specifically, any time more PHP code was executed as a "side-effect" of a non-fcall instruction, step out would get lost. In these cases the stack trace gives us the offset of the instruction causing the PHP to run, not the instruction that control will return to as is the case with a Fcall. A breakpoint set there would get missed. This changes the step out logic to recognize such cases (via the fact that a nested VM state was pushed to execute the code) and step out more intelligently. We look at the instruction in question, and determine where execution may go, which might be multiple places. I also made a small change to ensure that we don't stop in generated functions when stepping out, which cleans up the iterator experience quite a bit, and sets us up for proper generator stepping, which will come next.
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.