Hello everyone!
So, as advertised last week, I spent some time running the testsuite again. And as usual, it helped spot and even fix a few bugs. First of all, Ingo fixed the stack alignment in Haiku. This means the workarounds I had introduced in WebKit to get the JavaScript engine to run could now be removed. This was necessary, because the JavaScript engine in WebKit now uses the C stack for JS stuff (before it used a separate stack, which was properly aligned). Well, with this issue fixed, I could even enable the DFG JIT. DFG stands for “Data Flow Graph”. This is another level of JIT in webKit, that is used when a method is called relatively often (about 70 times) or loops a lot (more than 1000 iterations). This new JIT is able to optimize the code according to execution statistics and other heuristics. But, the initial optimization work is a bit expensive. That’s why it’s only used for “hot” areas in the code.
This is a companion discussion topic for the original entry at https://www.haiku-os.org/blog/pulkomandy/2014-02-21_webkit_weekly_report_20/