Bug 162978 – [DOMJIT] Support slow path call

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Yusuke Suzuki]

DOMJIT::Patchpoint (Maybe, DOMJIT::PatchpointParams) should have ability to request slow path call in both DFG and FTL!

[Yusuke Suzuki]

If we expose variadic template-ed slow path generator that calls DFG / FTL slow path generators, it exposes almost all the DFG and FTL.
For example, I tested the above design. And I ends up with exposing DFGSpeculativeJIT! That's bad.

Instead, I'll take callOperation like design. We list up necessary calls in DFGSlowPathCall.h. And it will invoke DFG / FTL's appropriate functionality in DFGSlowPathCall.cpp.

[Yusuke Suzuki]

Created attachment 290802 [details]
Patch

[Saam Barati]

Comment on attachment 290802 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=290802&action=review

> Source/JavaScriptCore/domjit/DOMJITSlowPathCalls.h:32
> +#define DOMJIT_SLOW_PATH_CALLS(macro) \
> +    macro(J_JITOperation_EP, JSValueRegs, GPRReg) \

I wonder if it ever makes sense to expose a call API that's more abstract like this:

class Call {
      struct Argument {
              Argument(GPRReg);
              Argument(JSValueRegs);
              Argument(immediate type: int32/int64/pointer); 
      }
      Type m_resultType;
      Vector<Arguments> m_arguments;
      FunctionPtr m_function;
};
and then have a function like:
setupCallWithExecState(const Call& call);

> Source/JavaScriptCore/ftl/FTLDOMJITPatchpointParams.cpp:41
> +    params.addLatePath([=] (CCallHelpers& jit) {

I wonder if it ever makes sense to have a normal call API.

[Yusuke Suzuki]

Comment on attachment 290802 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=290802&action=review

>> Source/JavaScriptCore/ftl/FTLDOMJITPatchpointParams.cpp:41
>> +    params.addLatePath([=] (CCallHelpers& jit) {
> 
> I wonder if it ever makes sense to have a normal call API.

Oops, thanks. It's OK. fixed.

[Yusuke Suzuki]

Comment on attachment 290802 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=290802&action=review

>> Source/JavaScriptCore/domjit/DOMJITSlowPathCalls.h:32
>> +    macro(J_JITOperation_EP, JSValueRegs, GPRReg) \
> 
> I wonder if it ever makes sense to expose a call API that's more abstract like this:
> 
> class Call {
>       struct Argument {
>               Argument(GPRReg);
>               Argument(JSValueRegs);
>               Argument(immediate type: int32/int64/pointer); 
>       }
>       Type m_resultType;
>       Vector<Arguments> m_arguments;
>       FunctionPtr m_function;
> };
> and then have a function like:
> setupCallWithExecState(const Call& call);

Looks clean. I filed it in https://bugs.webkit.org/show_bug.cgi?id=163099

[Yusuke Suzuki]

Comment on attachment 290802 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=290802&action=review

>>> Source/JavaScriptCore/ftl/FTLDOMJITPatchpointParams.cpp:41
>>> +    params.addLatePath([=] (CCallHelpers& jit) {
>> 
>> I wonder if it ever makes sense to have a normal call API.
> 
> Oops, thanks. It's OK. fixed.

But, after considering, the above one is still useful. We can emit slow path after the fast path sequence by using addLatePath.

[Yusuke Suzuki]

Committed r206899: <http://trac.webkit.org/changeset/206899>