- 01 Aug, 2017 1 commit
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Benedikt Meurer authored
The @@toStringTag lookup in Object.prototype.toString causes quite a lot of overhead and oftentimes dominates the builtin performance. These lookups are almost always negative, especially for primitive values, and Object.prototype.toString is often used to implement predicates (like in Node core or in AngularJS), so having a way to skip the negative lookup yields big performance gains. This CL introduces a "MayHaveInterestingSymbols" bit on every map, which says whether instances with this map may have an interesting symbol. Currently only @@toStringTag is considered an interesting symbol, but we can extend that in the future. In the Object.prototype.toString we can use the interesting symbols bit to do a quick check on the prototype chain to see if there are any maps that might have the @@toStringTag, and if not, we can just immediately return the result, which is very fast because it's derived from the instance type. This also avoids the ToObject conversions for primitive values, which is important, since this causes unnecessary GC traffic and in for example AngularJS, strings are also often probed via the Object.prototype.toString based predicates. This boosts Speedometer/AngularJS by over 3% and Speedometer overall by up to 1%. On the microbenchmark from the similar SpiderMonkey bug (https://bugzilla.mozilla.org/show_bug.cgi?id=1369042), we go from roughly 450ms to 70ms, which corresponds to a 6.5x improvement. ``` function f() { var res = ""; var a = [1, 2, 3]; var toString = Object.prototype.toString; var t = new Date; for (var i = 0; i < 5000000; i++) res = toString.call(a); print(new Date - t); return res; } f(); ``` The design document at https://goo.gl/e8CruQ has some additional data points. TBR=ulan@chromium.org Bug: v8:6654 Change-Id: I31932cf41ecddad079d294e2c322a852af0ed244 Reviewed-on: https://chromium-review.googlesource.com/593620 Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Reviewed-by: Camillo Bruni <cbruni@chromium.org> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org> Cr-Commit-Position: refs/heads/master@{#47034}
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- 13 Jul, 2017 1 commit
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Clemens Hammacher authored
There is just one version now, called IsPowerOfTwo. It accepts any integral type. There is one slight semantical change: Called with kMinInt, it previously returned true, because the argument was implicitly casted to an unsigned. It's now (correctly) returning false, so I had to add special handlings of kMinInt in machine-operator-reducer before calling IsPowerOfTwo on that value. R=mlippautz@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,ishell@chromium.org,yangguo@chromium.org Change-Id: Idc112a89034cdc8c03365b778b33b1c29fefb38d Reviewed-on: https://chromium-review.googlesource.com/568140Reviewed-by: Igor Sheludko <ishell@chromium.org> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Reviewed-by: Yang Guo <yangguo@chromium.org> Commit-Queue: Clemens Hammacher <clemensh@chromium.org> Cr-Commit-Position: refs/heads/master@{#46627}
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- 29 Jun, 2017 1 commit
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titzer authored
R=marja@chromium.org BUG= Review-Url: https://codereview.chromium.org/2961253002 Cr-Commit-Position: refs/heads/master@{#46321}
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- 16 Jun, 2017 1 commit
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Camillo Bruni authored
Change-Id: If9debcecd714494e24adf895eb077d5ba51528d2 Reviewed-on: https://chromium-review.googlesource.com/535619 Commit-Queue: Camillo Bruni <cbruni@chromium.org> Reviewed-by: Mythri Alle <mythria@chromium.org> Reviewed-by: Igor Sheludko <ishell@chromium.org> Cr-Commit-Position: refs/heads/master@{#45979}
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- 14 Jun, 2017 1 commit
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Ulan Degenbaev authored
This patch also changes the visitor of BytecodeArray to use BytecodeArray::BodyDescriptor. BUG=chromium:733159 Change-Id: I2ac72c97ec51996b5b100c447b543895180f4f78 Reviewed-on: https://chromium-review.googlesource.com/535674Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Commit-Queue: Ulan Degenbaev <ulan@chromium.org> Cr-Commit-Position: refs/heads/master@{#45955}
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- 12 Jun, 2017 1 commit
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Marja Hölttä authored
BUG=v8:5402,v8:6474 Cq-Include-Trybots: master.tryserver.v8:v8_linux_noi18n_rel_ng Change-Id: Id38249fe9dc88001218aa1faa1b31c9d2f9703d1 Reviewed-on: https://chromium-review.googlesource.com/528102 Commit-Queue: Marja Hölttä <marja@chromium.org> Reviewed-by: Jakob Gruber <jgruber@chromium.org> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org> Cr-Commit-Position: refs/heads/master@{#45853}
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