[webkit-changes] [WebKit/WebKit] 01b454: [JSC] TypedArray construction should scan JSArray ...

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 01b454ac1e6860442583d4b6157857047dc8a616
      https://github.com/WebKit/WebKit/commit/01b454ac1e6860442583d4b6157857047dc8a616
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-07-20 (Thu, 20 Jul 2023)

  Changed paths:
    A JSTests/microbenchmarks/typed-array-new-from-double-array-to-float64-typed-array.js
    M Source/JavaScriptCore/runtime/JSGenericTypedArrayView.h
    M Source/JavaScriptCore/runtime/JSGenericTypedArrayViewInlines.h
    M Source/JavaScriptCore/runtime/JSGenericTypedArrayViewPrototypeFunctions.h
    M Source/WTF/wtf/text/StringCommon.h
    M Source/WTF/wtf/text/StringImpl.h
    M Tools/TestWebKitAPI/Tests/WTF/StringCommon.cpp

  Log Message:
  -----------
  [JSC] TypedArray construction should scan JSArray in faster way
https://bugs.webkit.org/show_bug.cgi?id=259241
rdar://112315641

Reviewed by Michael Saboff.

Use SIMD function to convert JSValue to TypedArray destination types.
By leveraging ARM64 ld2, ld4, we can extract Int32 from JSValue efficiently, and we can store
them to destination.

1. Extract StringImpl::copyCharacters and define WTF::copyElements. It does super fast SIMD copies based on source and destination types.
   It can include widening or narrowing (so source and destination types may be different).
2. Use WTF::copyElements in TypedArray#from and TypedArray constructors.

                                                     ToT                     Patched

typed-array-from-array                        134.4441+-0.4424     ^     13.6653+-0.1270        ^ definitely 9.8383x faster
typed-array-new-from-int32-array               14.5654+-0.0179     ^      2.5779+-0.0212        ^ definitely 5.6501x faster
typed-array-new-from-double-array-to-float64-typed-array
                                                6.0447+-0.0299     ^      3.7598+-0.0156        ^ definitely 1.6077x faster

* JSTests/microbenchmarks/typed-array-new-from-double-array-to-float64-typed-array.js: Added.
(test):
* Source/JavaScriptCore/runtime/JSGenericTypedArrayViewInlines.h:
(JSC::JSGenericTypedArrayView<Adaptor>::setFromArrayLike):
* Source/JavaScriptCore/runtime/JSGenericTypedArrayViewPrototypeFunctions.h:
(JSC::genericTypedArrayViewPrivateFuncFromFast):
* Source/WTF/wtf/text/StringCommon.h:
(WTF::copyElements):
* Source/WTF/wtf/text/StringImpl.h:
(WTF::StringImpl::copyCharacters):

Canonical link: https://commits.webkit.org/266182@main