Bug 181953

Summary:

Split objects that have indexed properties from normal objects.

Product:

WebKit

Reporter:

Keith Miller <keith_miller>

Component:

JavaScriptCore

Assignee:

Keith Miller <keith_miller>

Status:

NEW

Severity:

Normal

CC:

dominik.infuehr, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
WIP	none
WIP	none
WIP more tests pass	none
Patch	none
WIP	none

Keith Miller

Reported 2018-01-22 14:36:20 PST

The current approach we have for handling indexed properties, index masking, works pretty well but it has a large perf cost. We think a large part of this cost is the extra allocation size for JSFinalObjects. Almost all JSFinalObjects don't have indexed properties. Thus, if we split the butterfly into two buffers where every object has named property storage (replacing butterfly) and all indexed objects have a second pointer containing indexed properties, we will save space on most objects. If a non-JSArray gets an indexed property later we can allocate an buffer object and put it in the named property storage.

Attachments
WIP (281.78 KB, patch) 2018-01-24 15:22 PST, Keith Miller	no flags	Details Formatted Diff Diff
WIP (736.95 KB, patch) 2018-02-19 14:12 PST, Keith Miller	no flags	Details Formatted Diff Diff
WIP more tests pass (780.27 KB, patch) 2018-03-12 12:09 PDT, Keith Miller	no flags	Details Formatted Diff Diff
Patch (798.84 KB, patch) 2018-03-22 08:24 PDT, Keith Miller	no flags	Details Formatted Diff Diff
WIP (798.88 KB, patch) 2018-03-26 02:03 PDT, Keith Miller	no flags	Details Formatted Diff Diff
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