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Emscripten Compiler Gets Optimizations, Now Self-Hosting 60

Emscripten is an LLVM-based compiler from dozens of languages to JavaScript (previously demoed as a repl and used to port Doom to the browser), and some recent changes have made it a bit faster, and allowed it to compile itself. Some highlights include a redundant variable eliminator, parallelization of the optimizier and compiler, and a new relooper. From the developer's weblog: "With all of the emscripten optimization passes now in JavaScript, I then worked on parallelizing that. ... The speedup can be close to linear in the number of cores. ... For the LLVM to JS compiler, I made the emscripten compiler parallel as well: It splits up the LLVM IR into 3 main parts: type data, function data, and globals. The function data part is unsurprisingly by far the largest in all cases I checked (95% or so), and it can in principle be parallelized - so I did that. Like in the optimizer, we use a Python process pool which feeds chunks of function data to multiple JavaScript compiler instances. There is some overhead due to chunking, and the type data and globals phases are not parallelized, but overall this can be a close to linear speedup. ... [On the new relooper] Note that this update makes Emscripten a 'self-hosting compiler' in a sense: one of the major optimization passes must be compiled to JS from C++, using Emscripten itself. Since this is an optimization pass, there is no chicken-and-egg problem: We bootstrap the relooper by first compiling it without optimizations, which works because we don't need to reloop there. We then use that unoptimized build of the relooper (which reloops properly, but slowly since it itself is unoptimized) in Emscripten to compile the relooper once more, generating the final fully-optimized version of the relooper, or 'relooped relooper' if you will."
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Emscripten Compiler Gets Optimizations, Now Self-Hosting

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  • DOOM (Score:4, Informative)

    by Dan East ( 318230 ) on Monday November 12, 2012 @09:29PM (#41962665) Journal

    I followed the link to Doom (and the next link, and the next link...) until I finally got to:

    Harvey Anderson
    Mozilla Corporation
    650 Castro Street, Suite 300
    Mountain View, CA 94041
    Email: dmcanotice@mozilla.com
    Phone Number: 650-903-0800
    Fax: 650-903-0875

    Re: DOOM on browser available on Mozilla website - Cease and Desist Notice - DMCA Notice of Copyright Infringement

    Dear Mr. Anderson:

    In accordance with Mozilla’s copyright infringement policy, this is to notify you of activity occurring on the Mozilla site listed below which infringes on the exclusive intellectual property rights of Id Software LLC, a wholly owned subsidiary of ZeniMax Media Inc. The copyrighted work at issue is Id Software’s proprietary software game DOOM® (“DOOM”). The link below offers an unauthorized derivation or version of Id Software’s DOOM game.

    https://developer.mozilla.org/en-US/demos/detail/doom-on-the-web/ [mozilla.org]

    DOOM is a registered trademark and the game assets are copyrighted material. Use of the mark DOOM and copyrighted assets without our authorization and consent, directly violates our trademark and copyright rights in and to such intellectual property. We hereby demand the immediate removal of all such links from your website and written assurance that you will prevent any further infringement of Id Software’s intellectual property rights. I have a good faith belief that use of the copyrighted materials described above as allegedly infringing is not authorized by the copyright owner, its agent, or the law. I swear, under penalty of perjury, that the information in this notification is accurate and that I am the copyright owner or am authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.


    Joshua Gillespie

    Associate General Counsel
    ZeniMax Media Inc.
    1370 Piccard Dr., #120
    Rockville, MD 20850
    T: 301.948.2200
    Email: jgillespie@zenimax.com

  • by IamTheRealMike ( 537420 ) on Tuesday November 13, 2012 @06:13AM (#41965481)

    The wikipedia page you reference states explicitly that he was acquitted of all charges in the criminal suit (and is therefore NOT a known criminal), and he agreed to be banned from banking to make a civil suit go away. That suit was never resolved, so we don't really have any idea whether he was guilty or not - he might have agreed on the basis that he was tired of defending himself in court and didn't care much for being a banker anyway. Let's face it, settlements in the face of expensive yet questionable government prosecutions are hardly rare, especially in the USA.

    The rest of the wild claims you assert aren't supported by any of the wiki pages either. Maybe it's all true but it's impossible to tell from your post. At any rate, it has nothing to do with the fact that DOOMs artwork and level data is still under copyright. If you want to get pissy at somebody about that, go complain to Carmack - he's the one who decided to open source the code but not the game data. Or not: he does a lot more for open source than most game company CEOs do.

The unfacts, did we have them, are too imprecisely few to warrant our certitude.