[WebGPU] built-in arrayLength assumes all buffers require an arrayLength, when it should not

[mwyrzykowski]

d7c9c0b

[WebGPU] built-in arrayLength assumes all buffers require an arrayLength, when it should not
https://bugs.webkit.org/show_bug.cgi?id=262728
<radar://116539036>

Reviewed by Dan Glastonbury.

In 268884@main, a buffer length for all buffers was generated. This is not
really needed.

Instead, generate a buffer length only when it is needed in the shader.

* Source/WebGPU/WGSL/GlobalVariableRewriter.cpp:
(WGSL::RewriteGlobalVariables::determineUsedGlobals):
* Source/WebGPU/WGSL/WGSL.h:
* Source/WebGPU/WebGPU/BindGroup.mm:
(WebGPU::Device::createBindGroup):
* Source/WebGPU/WebGPU/BindGroupLayout.mm:
(WebGPU::createArgumentDescriptor):
(WebGPU::Device::createBindGroupLayout):
(WebGPU::BindGroupLayout::bufferSizeIndexForEntryIndex const):
* Source/WebGPU/WebGPU/RenderPipeline.mm:
(WebGPU::Device::addPipelineLayouts):
* Source/WebGPU/WebGPU/WebGPUExt.h:

Canonical link: https://commits.webkit.org/268969@main

71a8efc

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[webkit-early-warning-system]

EWS run on current version of this PR (hash 71a8efc)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt		🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[djg]

[webkit-commit-queue]

Committed 268969@main (d7c9c0b): https://commits.webkit.org/268969@main

Reviewed commits have been landed. Closing PR #18718 and removing active labels.