Re: Removing --enable-shared-js [Was: Rust and --enable-shared-js]

2019-08-14 Thread Henri Sivonen
On Tue, Aug 13, 2019 at 2:18 PM Lars Hansen  wrote:
> Cranelift should be genuinely optional until further notice; to my 
> knownledge, no near-term product work in Firefox or SpiderMonkey depends on 
> Cranelift.  Cranelift is present in Nightly but (so far as I can tell) not in 
> Release. It can be disabled in the JS shell by configuring with 
> --disable-cranelift, and I just tested that this works.  To the extent there 
> is other Rust code in SpiderMonkey it should not, so far as I know, depend on 
> the presence of Cranelift.  It also seems to me that we should be able to use 
> Rust in SpiderMonkey independently of whether Cranelift is there, so if that 
> does not work it ought to be fixed.

Thanks. That makes sense to me.

The present state (now that
https://bugzilla.mozilla.org/show_bug.cgi?id=1572364 has landed) is
that when built as part of libxul, SpiderMonkey can use Rust code
(jsrust_shared gets built) regardless of whether Cranelift is enabled.
However, when SpiderMonkey is built outside libxul, SpiderMonkey can
use Rust code (jsrust_shared gets built) only if Cranelift is enabled.
I've filed https://bugzilla.mozilla.org/show_bug.cgi?id=1573098 to
change that.

(The actual addition of non-Cranelift Rust code of interest to
jsrust_shared hasn't landed yet.)

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Henri Sivonen
hsivo...@mozilla.com
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Re: Removing --enable-shared-js [Was: Rust and --enable-shared-js]

2019-08-13 Thread Lars Hansen
Cranelift should be genuinely optional until further notice; to my
knownledge, no near-term product work in Firefox or SpiderMonkey depends on
Cranelift.  Cranelift is present in Nightly but (so far as I can tell) not
in Release. It can be disabled in the JS shell by configuring with
--disable-cranelift, and I just tested that this works.  To the extent
there is other Rust code in SpiderMonkey it should not, so far as I know,
depend on the presence of Cranelift.  It also seems to me that we should be
able to use Rust in SpiderMonkey independently of whether Cranelift is
there, so if that does not work it ought to be fixed.

--lars

On Wed, Aug 7, 2019 at 3:53 PM Henri Sivonen  wrote:

> On Tue, May 28, 2019 at 3:16 AM Mike Hommey  wrote:
> >
> > On Tue, May 21, 2019 at 10:32:20PM -0400, Boris Zbarsky wrote:
> > > On 5/21/19 9:55 PM, Mike Hommey wrote:
> > > > Considering this has apparently been broken for so long, I guess
> nobody
> > > > will object to me removing the option for Gecko builds?
> > >
> > > It's probably fine, yeah...
> >
> > Now removed on autoland via bug 1554056.
>
> Thanks.
>
> It appears that building jsrust_shared is still conditional on
> ENABLE_WASM_CRANELIFT. How optional is ENABLE_WASM_CRANELIFT in
> practice these days? Is it genuinely optional for Firefox? Is it
> genuinely optional for standalone SpiderMonkey? If it is, are we OK
> with building without ENABLE_WASM_CRANELIFT having other non-Cranelift
> effects on SpiderMonkey performance (e.g. turning off SIMD for some
> operations) or on whether a particular string conversion is available
> in jsapi.h?
>
> I'm trying to understand the implication of Cranelift being optional
> for other Rust code in SpiderMonkey. I'd like to add Rust-backed
> SIMD-accelerated Latin1ness checking and UTF-8 validity checking to
> SpiderMonkey and Rust-backed conversion from JSString to UTF-8 in
> jsapi.h, and my understanding from All Hands was that adding these
> things would be OK, since SpiderMonkey already depends on Rust.
>
> --
> Henri Sivonen
> hsivo...@mozilla.com
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Re: Removing --enable-shared-js [Was: Rust and --enable-shared-js]

2019-08-07 Thread Henri Sivonen
On Tue, May 28, 2019 at 3:16 AM Mike Hommey  wrote:
>
> On Tue, May 21, 2019 at 10:32:20PM -0400, Boris Zbarsky wrote:
> > On 5/21/19 9:55 PM, Mike Hommey wrote:
> > > Considering this has apparently been broken for so long, I guess nobody
> > > will object to me removing the option for Gecko builds?
> >
> > It's probably fine, yeah...
>
> Now removed on autoland via bug 1554056.

Thanks.

It appears that building jsrust_shared is still conditional on
ENABLE_WASM_CRANELIFT. How optional is ENABLE_WASM_CRANELIFT in
practice these days? Is it genuinely optional for Firefox? Is it
genuinely optional for standalone SpiderMonkey? If it is, are we OK
with building without ENABLE_WASM_CRANELIFT having other non-Cranelift
effects on SpiderMonkey performance (e.g. turning off SIMD for some
operations) or on whether a particular string conversion is available
in jsapi.h?

I'm trying to understand the implication of Cranelift being optional
for other Rust code in SpiderMonkey. I'd like to add Rust-backed
SIMD-accelerated Latin1ness checking and UTF-8 validity checking to
SpiderMonkey and Rust-backed conversion from JSString to UTF-8 in
jsapi.h, and my understanding from All Hands was that adding these
things would be OK, since SpiderMonkey already depends on Rust.

-- 
Henri Sivonen
hsivo...@mozilla.com
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Re: Removing --enable-shared-js [Was: Rust and --enable-shared-js]

2019-05-27 Thread Mike Hommey
On Tue, May 21, 2019 at 10:32:20PM -0400, Boris Zbarsky wrote:
> On 5/21/19 9:55 PM, Mike Hommey wrote:
> > Considering this has apparently been broken for so long, I guess nobody
> > will object to me removing the option for Gecko builds?
> 
> It's probably fine, yeah...

Now removed on autoland via bug 1554056.

Mike
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Re: Removing --enable-shared-js [Was: Rust and --enable-shared-js]

2019-05-21 Thread Boris Zbarsky

On 5/21/19 9:55 PM, Mike Hommey wrote:

Considering this has apparently been broken for so long, I guess nobody
will object to me removing the option for Gecko builds?


It's probably fine, yeah...

-Boris
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Removing --enable-shared-js [Was: Rust and --enable-shared-js]

2019-05-21 Thread Mike Hommey
Hi,

I'm revisiting the topic of --enable-shared-js for Gecko builds for
different reasons than the one that started this thread.

On Mon, Sep 24, 2018 at 08:24:43AM -0400, Boris Zbarsky wrote:
> My use case for it is to be able to use the "exclude samples from library X"
> or "collapse library X" tools in profilers (like Instruments) to more easily
> break down profiles into "page JS" and "Gecko things".
> 
> That said, I haven't done that very much recently...

And my guess nobody has done that since, nor for a while, because the
way an attempt to build with --enable-shared-js fails leaves me thinking
this has been broken at least since bug 1436179 landed... a year ago.

Considering this has apparently been broken for so long, I guess nobody
will object to me removing the option for Gecko builds?

On Tue, Oct 02, 2018 at 09:29:51AM -0500, Luke Wagner wrote:
> (Sorry, I polled #jsapi about this issue back when you first posted and
> then forgot to reply with the response.)
> 
> It doesn't seem like any SM devs use --enable-shared-js for their own
> development but we do know that various embedders (e.g. GNOME) use the JS
> shared library and so we'd like to keep that configuration tested and
> working.  One hybrid option is thus:
>  - drop support for building Gecko with --enable-shared-js (avoiding the
> symbol conflict issue), but keep --enable-shared-js as a configure option
> for JS shell builds
>  - have at least one tier-1 --enable-shared-js JS shell build on automation
> so that we at least keep it working

It's worth noting that --enable-shared-js is already the default when
building spidermonkey standalone.

Mike
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