chakra-core/ChakraCore

Optimize OP_LdCustomSpreadIteratorList for arguments object

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#1,230 创建于 2016年7月1日

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 (10 评论) (0 反应) (0 负责人)JavaScript (9,000 star) (1,374 fork)batch import
PerformanceProposalSuggestiongood first issuehelp wanted

描述

I was looking into the code of OP_LdCustomSpreadIteratorList and noticed that we optimize it by not creating SpreadArgument if parameter passed to OP_LdCustomSpreadIteratorList does not have user defined iterator. We do this check only for JavascriptArray and TypedArrayBase and we can expand it for ArgumentsObject as well. As per spec, both unmapped and mapped argument objects has default @@iterator set to Array.proto.values.

贡献者指南

技术栈
cppjavascript
领域
performance
议题类型
performance
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
5
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
3-5 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
C++ proficiencyUnderstanding of JavaScript iteratorsChakraCore codebase familiarityBasic knowledge of ES6 spread operator
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
10
研究方向
Examine the existing optimization in lib/Runtime/Language/JavascriptOperators.cpp at line 1405. Understand how the check for non user defined iterator is done for JavascriptArray and TypedArrayBase. Then extend the same logic to ArgumentsObject, ensuring that the arguments object's default iterator (Array.prototype.values) is used. Consider edge cases where the arguments object might have its @@iterator overridden. Write tests to cover the optimization.
Optimize OP_LdCustomSpreadIteratorList for arguments object · chakra-core/ChakraCore#1230 | Good First Issue