[webkit-dev] SH4, MIPS, and legacy-ARM assemblers in JavaScriptCore

[Fu, Chao-Ying]

Hi Filip,

  We (MIPS Technologies) have customers that ship MIPS Qt WebKit and
Android that uses WebKit JSC.  Also, we are working on the new interpreter and the new JIT.
We think it would be ready in two months to contribute our code to webkit.org.

  We have a nightly cron job that checks out source code from webkit.org, 
built, run regression tests, and run SunSpider tests.  Also, I think there is
a buildbot for Qt Linux MIPS Release there.
http://trac.webkit.org/wiki/QtWebKitBuildBots

  If you need to add or change assembler APIs, please let me know and we will be very
happy to work on it from the MIPS side.  Thanks a lot!

Regards,
Chao-ying


> -----Original Message-----
> From: webkit-dev-bounces at lists.webkit.org 
> [mailto:webkit-dev-bounces at lists.webkit.org] On Behalf Of Filip Pizlo
> Sent: Thursday, June 21, 2012 3:50 PM
> To: WebKit Development
> Subject: [webkit-dev] SH4, MIPS, and legacy-ARM assemblers in 
> JavaScriptCore
> 
> Hi all,
> 
> We are actively trying to improve the WebKit JavaScript 
> engine (JavaScriptCore), with new debugging, profiling, 
> memory efficiency, and performance features.  Because 
> JavaScriptCore is a JIT-based engine, this inevitably means 
> doing JIT work, which in turn includes adding new 
> instructions to the JIT assemblers and changing the API 
> between the assemblers and the JIT.
> 
> Currently, the maintenance situation in the assembler layer 
> is not great.  We have three well-supported assemblers, 
> X86-32, X86-64, and ARMv7. Then we have three assemblers that 
> appear to be on life support: legacy (non-THUMB2, pre-v7) 
> ARM, SH4, and MIPS.  It is increasingly painful to maintain 
> these three barely-supported assemblers.  None of these 
> assemblers has been updated to support the new JIT or 
> interpreter infrastructure, and there appears to be no 
> ongoing effort to do so.  That means that for progress to be 
> made on X86 and ARMv7, we need to increasingly scatter #if 
> ENABLE(...) noise throughout the system to keep those other 
> assemblers building.  Neither the active JavaScriptCore 
> contributors, nor those running the bots for those hardware 
> platforms, appear to have much interest in maintaining those 
> assemblers, other than the occasional build fix.
> 
> This is not a good situation to be in.
> 
> So, I am curious: is anyone shipping with the legacy ARM 
> assembler, the MIPS assembler, or the SH4 assembler?
> 
> As a secondary question, if you are shipping the legacy ARM 
> assembler, are you doing so because you have legacy ARM 
> hardware or because you have not had the chance to switch to 
> the new ARM assembler in your codebase?
> 
> -Filip
> 
> 
> _______________________________________________
> webkit-dev mailing list
> webkit-dev at lists.webkit.org
> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>