179230 2017-11-02 21:34:42 -0700 Web Tooling Benchmark: fix RegExp pathologies 2018-09-05 11:25:24 -0700 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 180537 180538 180874 180876 1 jfbastien msaboff ap fpizlo jfbastien keith_miller mark.lam mjs msaboff rmorisset saam webkit-bug-importer oldest_to_newest 1367769 0 jfbastien 2017-11-02 21:34:42 -0700 We seem pathologically slow on the coffeescript part of Web Tooling Benchmark: https://v8.github.io/web-tooling-benchmark/ Source: https://github.com/bmeurer/web-tooling-benchmark I get 0.22 runs / sec on STP 42, versus 8.24 runs / sec on Chrome 61. 1367776 1 jfbastien 2017-11-02 21:46:07 -0700 Non-fork source is actually: https://github.com/v8/web-tooling-benchmark 1368133 2 saam 2017-11-03 13:57:06 -0700 We're spending all our time interpreting these RegExps: ^\s*###([^#][\s\S]*?)(?:###[^\n\S]*|###$)|^(?:\s*#(?!##[^#]).*)+ 8014.546220ms ^(?!\d)((?:(?!\s)[$\w\x7f-\uffff])+)([^\n\S]*:(?!:))? 8179.496043ms ^\/(?!\/)((?:[^[\/\n\\]|\\[^\n]|\[(?:\\[^\n]|[^\]\n\\])*\])*)(\/)? 2951.752059ms ^(?:[-=]>|[-+*\/%<>&|^!?=]=|>>>=?|([-+:])\1|([&|<>*\/%])\2=?|\?(\.|::)|\.{2,3}) 2888.876650ms Michael believes we will get much faster if we JIT these patterns. 1368160 3 webkit-bug-importer 2017-11-03 14:40:26 -0700 <rdar://problem/35343582> 1382220 4 msaboff 2017-12-15 11:35:32 -0800 Originally, the main RegExp issue was with the coffeescript test which spent most of its time in the aforementioned 4 regular expressions. Adding JIT support for greedy sub patterns (https://bugs.webkit.org/show_bug.cgi?id=180538) addressed some of these RegExp's. There is still the need to add JIT support for back references (https://bugs.webkit.org/show_bug.cgi?id=180874) to address the remaining Yarr interpreter use in coffeescript. Since this bug was created, the Web Tooling benchmark has changed. A few new tests have been added. Two of those new tests, acorn and espree, spend significant time in the Yarr interpreter evaluating non-greedy sub patterns. That work is tracked in https://bugs.webkit.org/show_bug.cgi?id=180876. 1456801 5 msaboff 2018-09-05 11:25:24 -0700 We now have JIT support for greedy and non-greedy nested sub patterns, and back references including case ignore for 8 bit strings.