[webkit-dev] x86-64 JIT

[Mike Hommey]

On Tue, Mar 17, 2009 at 05:09:10PM -0700, Maciej Stachowiak wrote:
>
> On Mar 17, 2009, at 1:51 PM, Mike Hommey wrote:
>
>> Hi,
>>
>> I was taking a quick look at the JIT code and also gave a shot at
>> forcing a build of the x86-64 code under Linux.
>>
>> The main problem right now is the following:
>> ../JavaScriptCore/jit/JITArithmetic.cpp:664: error: cast from  
>> 'JSC::Structure*' to 'unsigned int' loses precision
>> ../JavaScriptCore/jit/JITArithmetic.cpp:674: error: cast from  
>> 'JSC::Structure*' to 'unsigned int' loses precision
>> ../JavaScriptCore/jit/JITArithmetic.cpp:714: error: cast from  
>> 'JSC::Structure*' to 'unsigned int' loses precision
>> ../JavaScriptCore/jit/JITArithmetic.cpp:724: error: cast from  
>> 'JSC::Structure*' to 'unsigned int' loses precision
>>
>> Looking at the code, it seems really too much x86-centric, and
>> depending on how the x86-64 ABI is under OSX. I don't know how things
>> are going to evolve with Snow-Leopard, as I hear the kernel will  
>> finally
>> be 64-bits, but maybe the same issue will arise.
>
> The x86_64 ABI is standardized, so it should match between Linux and OS X 
> for the things we care about.
>
>> Anyways, I'd need guidance from some people with JIT knowledge to help
>> me get it work on Linux.
>
> Sounds like either ALTERNATE_JSIMMEDIATE or JIT_OPTIMIZE_ARITHMETIC is  
> not defined for you. It should be defined on x86_64. But it also sounds 
> like a bug that pointers are being cast to unsigned in this code path. 
> I'm not sure offhand how to fix it. But making sure those two 
> preprocessor symbols are set should help.

Oh thanks, that was it. I removed one PLATFORM(MAC) for ENABLE_JIT but
missed the one for ALTERNATE_JSIMMEDIATE. It built. I'll check if it
works (and will probably enable it in the debian packages, so that it is
mode widely tested)

Mike