[webkit-dev] [jsc-dev] Proposal: Using LLInt Asm in major architectures even if JIT is disabled

[Filip Pizlo]

> On Sep 21, 2018, at 9:44 AM, Guillaume Emont <guijemont at igalia.com> wrote:
> 
> Quoting Yusuke Suzuki (2018-09-21 10:10:59)
>> Yeah, I'm not planning to enable LLInt ASM interpreter on 32bit architectures
>> since no buildbot exists for this configuration.
> 
> I'm confused. Do you mean you don't want to enable LLint instead of
> CLoop, for the case when JIT is disabled on 32-bit architectures?

If you guys want to take responsibility for 32-bit then you can enable whatever LLInt config you want on 32-bit.

> FTR, the configuration LLInt(with offlineasm)+jit+dfg is tested in
> 32-bit testbots for at least mips, armv7 and x86.
> 
> 
>> And we should make 32bit architectures JSVALUE64, so LLInt JSVALUE32_64 should
>> be removed in the future.
> 
> See what Filip and Michael were saying. We believe that we need
> JSVALUE32_64, and we are willing to maintain it, as the performance gap
> between LLInt or CLoop and JIT+DFG on 32-bit architectures is
> significant.

I’m saying we should remove JSVALUE32_64. That is my preference. I’m letting it stay in tree so long as someone maintains it, but honestly I’d prefer it if it wasn’t maintained and if we could let it die. 

I’d like to see the majority of JSC development move to 64-bit. I’d prefer if new features or enhancements were 64-bit only, since that means that it will take less time to develop and test them. I think that folks doing JSC development should be encouraged to land changes only for 64-bit since that’s our focus as a project.

-Filip

> 
> Guillaume
> 
>> 
>> On Fri, Sep 21, 2018 at 2:33 AM Michael Catanzaro <mcatanzaro at igalia.com>
>> wrote:
>> 
>>>    On Thu, Sep 20, 2018 at 12:02 PM, Filip Pizlo <fpizlo at apple.com> wrote:
>>> - Enable cloop/JSVALUE64 to work on 32-bit.  I don’t think it does
>>> right now, but that’s probably trivial to fix.
>>> - Switch Darwin ports to that configuration for 32-bit.
>>> - When changes land to support new features, make it mandatory to
>>> support JSVALUE64 and optional to support JSVALUE32_64.  Such changes
>>> should include whoever volunteers to maintain JSVALUE32_64 in CC.
>>> 
>>> If you guys consider JSVALUE32_64 to be critical, then you can go
>>> ahead and maintain it.  We’ll let JSVALUE32_64 stay in the tree so
>>> long as someone is maintaining it.
>> 
>>    Yes that's fine with us. I think that's the previous agreement, anyway.
>>    :)
>> 
>>    Michael
>> 
>> 
>> 
>> 
>> --
>> Best regards,
>> Yusuke Suzuki
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