Bug 143396 – In the 64-bit DFG and FTL, Array::Double case for HasIndexedProperty should set its result to true when all is well

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Mark Lam]

Currently, all other cases do set the result to true when in the successful path.  Only the Array::Double case has neglected to do so.  This bug does is only present in the 64-bit DFG.

[Mark Lam]

<rdar://problem/20096787>

[Mark Lam]

Turns out that the FTL implementation of HasIndexedProperty has a similar but different problem.  In this case, the FTL is setting the boolean result.  However, the value that it is setting it with needs to be inverted.

Michael helped me out with figuring out how to invert said bit.  My tests appear to be passing now.  Patch for fix coming soon.

[Mark Lam]

Created attachment 250226 [details]
the patch.

[Filip Pizlo]

Comment on attachment 250226 [details]
the patch.

View in context: https://bugs.webkit.org/attachment.cgi?id=250226&action=review

> Source/JavaScriptCore/ftl/FTLLowerDFGToLLVM.cpp:4712
> -                m_out.doubleNotEqualOrUnordered(doubleValue, doubleValue));
> -            m_out.branch(checkHoleResult.value(), rarely(slowCase), usually(continuation));
> +                m_out.bitNot(m_out.doubleNotEqualOrUnordered(doubleValue, doubleValue)));
> +            m_out.branch(checkHoleResult.value(), usually(continuation), rarely(slowCase));

You should just use doubleEqual() instead of bitNot(doubleNotEqualOrUnordered)

[Mark Lam]

Created attachment 250228 [details]
patch 2: with Fil's better doubles comparison.

[Mark Lam]

Thanks.  Landed in r182444: <http://trac.webkit.org/r182444>.