[webkit-reviews] review granted: [Bug 69215] Support string length in the DFG : [Attachment 109406] Patch

[bugzilla-daemon at webkit.org]

Geoffrey Garen <ggaren at apple.com> has granted Oliver Hunt <oliver at apple.com>'s
request for review:
Bug 69215: Support string length in the DFG
https://bugs.webkit.org/show_bug.cgi?id=69215

Attachment 109406: Patch
https://bugs.webkit.org/attachment.cgi?id=109406&action=review

------- Additional Comments from Geoffrey Garen <ggaren at apple.com>
View in context: https://bugs.webkit.org/attachment.cgi?id=109406&action=review


r=me

> Source/JavaScriptCore/dfg/DFGPropagator.cpp:715
>	       if (!isInt32Prediction(m_predictions[m_compileIndex]))
>		   break;

Not super important, but I think you're guaranteed to have an int once you have
an array / string .length property.

> Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp:1730
> +	   speculationCheck(m_jit.branch32(MacroAssembler::LessThan, resultGPR,
MacroAssembler::TrustedImm32(0)));

I believe we could remove this branch, and the branch on array length access,
if we changed array and string length to int from unsigned, and limited their
lengths to 2^31-1.