[webkit-dev] x86-64 JIT

Mike Hommey mh+webkit at glandium.org
Fri Mar 20 00:48:49 PDT 2009

On Thu, Mar 19, 2009 at 02:09:51PM -0700, Gavin Barraclough wrote:
> I think I can see a bug here – the compile guard on the definition of  
> VoidPtrPair in JITStubs.h isn't right.
> should be changed to
> (and the else case should #error if compiled on x86-64, if it not 64-bit 
> safe).
> The MSVC version of this structure works around a quirk in the windows  
> ABI in a way that is not 64-bit safe, and you shouldn't need this on  
> Linux.  The result of this will be resolve_func returning a junk  
> JSValuePtr for the function object.

You nailed it. Fixing this makes the JIT work on my laptop.
If you deem it necessary, I can file a bug and attach a patch for this
issue. I will, anyways, file a bug and attach a patch to enable JIT
on x86-64 for WebKitGtk later today.



PS: for the curious, some performance figures: On my laptop, sunspider
runs in 1685ms on x86-64 where the x86 version runs in 1965ms. But
that's without forcing the CPU to be fullspeed all the time in both
cases, which *does* improve sunspider results (and help have more stable

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