Thanks! > On Sep 16, 2019, at 4:39 AM, Xan <xan.lo...@gmail.com> wrote: > > Hi all, > > We at Igalia use the x86 32bit port for testing, prototyping, etc, in our > 32bit work. We recently added a JSC EWS x86 instance. > That being said only the LLInt tier is working properly at the moment, and if > the maintenance of the JIT code is a big burden we think it makes sense to > remove it.
Yes, x86 adds many special logic. You can see the actual diff, which involves many “only for x86” logic involving weird stack push/pop. And it is not well-abstracted. As a result, changes are in all of our JIT tiers (except for FTL b/c we are not supporting x86 in FTL) :( https://trac.webkit.org/changeset/249880/webkit <https://trac.webkit.org/changeset/249880/webkit> YarrJIT has HAVE_INITIAL_START_REG ifdef and separate logic, which is only for x86. All the other platforms including ARMv7 do not require this. If this architecture has enough # of registers (like, MIPS), keeping it would be much easier. But it only has very few registers and this makes x86 special compared to the other 32bit architectures. I also note that x86 JIT is not working for at least 3 months. I found that x86 callee-save-register definition is broken at some point[1]. [1]: https://trac.webkit.org/changeset/249830/webkit <https://trac.webkit.org/changeset/249830/webkit> > > This already happened during the weekend, so I guess this can count as an > after the fact tacit agreement. In the future we'd appreciate if we could > have at least a full week day (including Europe) to discuss these kinds of > changes though. OK, I see. -Yusuke > > Cheers, > Xan (on behalf of Igalia's compilers team) > > On Sat, Sep 14, 2019 at 9:32 PM Yusuke Suzuki <ysuz...@apple.com > <mailto:ysuz...@apple.com>> wrote: > Thanks! > > I think we are not testing x86 JIT configuration, and nobody is seriously > using it (Default build option for c86 is no JIT). Removed :D > > [1]: https://trac.webkit.org/changeset/249830/webkit > <https://trac.webkit.org/changeset/249830/webkit> > > Best regards, > Yusuke Suzuki > >> On Sep 13, 2019, at 15:08, Geoffrey Garen <gga...@apple.com >> <mailto:gga...@apple.com>> wrote: >> >> No objection. >> >> Geoff >> >>> On Sep 13, 2019, at 1:39 PM, Yusuke Suzuki <ysuz...@apple.com >>> <mailto:ysuz...@apple.com>> wrote: >>> >>> Hello all, >>> >>> Now, Xcode no longer has ability to build 32bit binary. >>> Fedora starts dropping x86 32bit kernel shipping. >>> Our x86/x86_64 JIT requires SSE2, so such CPUs can use JIT if they want by >>> switching x86 to x86_64. >>> And these CPUs are modern enough to run CLoop at high speed. >>> >>> x86 32bit JIT backend is very complicated and is being a major maintenance >>> burden. >>> This is due to very few # of registers. Which scatters a lot of isX86 / >>> CPU(X86) in Baseline, DFG, and Yarr. >>> I’m now planning to optimize some part of Yarr, but x86 YarrJIT is being a >>> major barrier of such cleanups / optimizations. >>> >>> So, I would like to propose dropping X86 32bit JIT support. >>> >>> -Yusuke >>> _______________________________________________ >>> webkit-dev mailing list >>> webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> >>> https://lists.webkit.org/mailman/listinfo/webkit-dev >>> <https://lists.webkit.org/mailman/listinfo/webkit-dev> >> > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org <mailto:webkit-dev@lists.webkit.org> > https://lists.webkit.org/mailman/listinfo/webkit-dev > <https://lists.webkit.org/mailman/listinfo/webkit-dev> > _______________________________________________ > webkit-dev mailing list > webkit-dev@lists.webkit.org > https://lists.webkit.org/mailman/listinfo/webkit-dev
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