关键词：JavaScript；JIT；分析框架；定位
摘 要：This paper presents JITPROF, a profiling framework to dynamically identify code locations that prohibit profitable JIT optimizations. The basic idea is to associate execution counters with potentially JIT-unfriendly code locations and to use these counters to report code locations that match code patterns known to prohibit optimizations. We instantiate the idea for six JIT-unfriendly code patterns that cause performance problems in the Firefox and Chrome browsers, and we apply the approach to popular benchmark programs.