chakra-core/ChakraCore

Optimize OP_LdCustomSpreadIteratorList for arguments object

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#1,230 opened on Jul 1, 2016

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PerformanceProposalSuggestiongood first issuehelp wanted

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Description

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.

Contributor guide

Research direction
Investigate how to extend the existing optimization in OP LdCustomSpreadIteratorList to check for ArgumentsObject, ensuring it does not have a user defined iterator, and modify the code in JavascriptOperators.cpp to apply the same logic as for JavascriptArray and TypedArrayBase.
Tech stack
cppjavascript
Domain
backend
Issue type
Performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++JavaScript
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25