Created attachment 516441 [details] [diff] [review]
This patch starts an rdtsc timer at function prologues, then takes the difference at the epilogue and adds it to script->ncycles. When a script is destroyed, its statistics are dumped like this:
jit prof (script "crypto.js") (line "243") (cycles 12250744) (hits 158295) (per 77)
There's no callgraph information or anything yet. This is quick and dirty and I'm not sure if it's enough to be helpful yet.
JM was removed, and there's pccounts + code to integrate with various profilers now.