I made substantial progress on getting emscripten::val to work in asm.js tonight. Just emscripten::val, not any of the function or class binding stuff.
https://github.com/imvu/emscripten/commits/master It no longer uses reinterpret_cast on function pointers. Instead it uses varargs. Unfortunately, my demo doesn't quite run yet. The old compiler had 8-byte alignment on varargs, but the new compiler appears to usually fit integers in 4 bytes. I'll need to find some way to switch off of whether asm.js is enabled in the embind JavaScript. Alon: do you know if there's an easy way to detect whether fastcomp or asm.js is enabled at runtime? Also, what _is_ the vararg convention for fastcomp/asm.js? Is it the same as asm.js in the old compiler? Or is fastcomp the new factor here? On Sun, Mar 23, 2014 at 12:48 AM, Chad Austin <[email protected]> wrote: > I found some time and got a few bits of embind working: > > > https://github.com/imvu/emscripten/commit/afc59d1e331c445a5762f6a5751b86740b1ebbeb > > https://github.com/imvu/emscripten/commit/228b4fc349f1cdf592821d988240e7d9543462be > > When I get a minimal demo up and running in fastcomp/asm.js, I'll submit a > pull request. > > > > On Mon, Mar 17, 2014 at 3:11 PM, Dean Elhard <[email protected]> wrote: > >> I would be interested in helping, although I haven't looked at how it >> works, so I am not sure what exactly is involved... >> >> >> On Wednesday, March 5, 2014 2:33:34 AM UTC-7, Chad Austin wrote: >> >>> True! We do want to use fastcomp but wasn't sure the advantages >>> outweighed the embind porting work. >>> >>> However, because Dean asked, I sat down and took a look tonight, and got >>> a few functions working. Most of the work is in getting rid of the >>> function pointer casts, but it seems quite straightforward. >>> >>> I'll poke away and send pull requests when I have them... If anyone >>> wants to help, let me know. :) >>> >>> >>> On Tue, Mar 4, 2014 at 8:27 PM, Alon Zakai <[email protected]> wrote: >>> >>>> Note that fastcomp supports a growable heap in asm.js mode. It will not >>>> validate as asm.js, but should still get much of the speedups from it, just >>>> without guarantees and probably not all of them. >>>> >>>> - Alon >>>> >>>> >>>> >>>> On Tue, Mar 4, 2014 at 2:46 PM, Chad Austin <[email protected]> wrote: >>>> >>>>> Hi Dean, >>>>> >>>>> We should port embind to asm.js! It's certainly a bit of work, but >>>>> probably not too hard. It's really just that nobody's done the work yet. >>>>> Since IMVU, my employer, can't use asm.js until it supports a growable >>>>> heap >>>>> (and perhaps closure compiler), we aren't terribly motivated to do the >>>>> work. >>>>> >>>>> That said, part of me just wants to bite the bullet and do the >>>>> conversion myself if I can find the time. :) >>>>> >>>>> In case someone else wants to take a crack at it, here is what I know: >>>>> >>>>> There are a couple places where embind uses reinterpret_cast on >>>>> function pointers in order to pass more arguments than their prototypes >>>>> specify. For example, see https://github.com/kripken/ >>>>> emscripten/blob/master/system/include/emscripten/val.h#L67 >>>>> >>>>> Those functions need to be converted to varargs. (At the time, I >>>>> think we were blocked on a varargs issue with the old LLVM, but that may >>>>> not be an issue anymore.) >>>>> >>>>> The other issue is that embind relies on JavaScript being able to look >>>>> up functions by indexing into FUNCTION_TABLE[x]. asm.js doesn't have a >>>>> single function table: it has a whole bunch of function tables, one for >>>>> each possible type signature. >>>>> >>>>> Thus, on the C++ side, we need a way to take a C++ signature (like >>>>> float(const void*, int&)) and turn that into a string ("fii") that we can >>>>> use to select one of the function tables on the embind side. Embind would >>>>> also need the compiler to output a table from signature to the appropriate >>>>> function table. The compiler-generated glue would look something like: >>>>> >>>>> var FUNCTION_TABLES = { >>>>> vi: FUNCTION_TABLE_vv, >>>>> fii: FUNCTION_TABLE_fii, >>>>> ... >>>>> }; >>>>> >>>>> I *think* that if we had those two things, we could make embind work >>>>> with asm.js. >>>>> >>>>> *waves hands a bit* :) >>>>> >>>>> Hope that's helpful, >>>>> Chad >>>>> >>>>> On Tue, Mar 4, 2014 at 2:28 PM, Dean Elhard <[email protected]>wrote: >>>>> >>>>>> Since 1.13.0 is moving to the fastcomp compiler, which only supports >>>>>> asm.js, and embind doesn't work with asm.js, it seems that anyone relying >>>>>> on embind is being left behind. >>>>>> >>>>>> The issues I see on github regarding embind and asm.js are old and >>>>>> inactive, and indicate no plans to make embind work with asm.js any time >>>>>> soon. >>>>>> >>>>>> Any comment on the future of embind (if any), or what will replace it? >>>>>> >>>>>> >>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "emscripten-discuss" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to [email protected]. >>>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Chad Austin >>>>> Technical Director, IMVU >>>>> http://engineering.imvu.com <http://www.imvu.com/members/Chad/> >>>>> http://chadaustin.me >>>>> >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "emscripten-discuss" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to [email protected]. >>>>> For more options, visit https://groups.google.com/groups/opt_out. >>>>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "emscripten-discuss" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>> >>> >>> >>> -- >>> Chad Austin >>> Technical Director, IMVU >>> http://engineering.imvu.com <http://www.imvu.com/members/Chad/> >>> http://chadaustin.me >>> >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "emscripten-discuss" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Chad Austin > Technical Director, IMVU > http://engineering.imvu.com <http://www.imvu.com/members/Chad/> > http://chadaustin.me > > > -- Chad Austin Technical Director, IMVU http://engineering.imvu.com <http://www.imvu.com/members/Chad/> http://chadaustin.me -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. 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