In library.js we ifdef on that in a few places, see formatString for example. Yes, this changes by compilation mode. We used to do 64-bit alignment all the time, but in fastcomp we use the pnacl varargs lowering pass, which does only 32-bit alignment. We should fix that eventually as it means doubles are slower in varargs.
- Alon On Mon, Mar 24, 2014 at 2:59 AM, Chad Austin <[email protected]> wrote: > 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. > 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. > -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. 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