[webkit-dev] Enabling the HTML5 tree builder soon
abarth at webkit.org
Wed Jul 28 20:13:03 PDT 2010
On Wed, Jul 28, 2010 at 6:06 AM, Stephanie Lewis <slewis at apple.com> wrote:
> I measure it as a 1% win on the PLT.
> -- Stephanie
> On Jul 26, 2010, at 12:36 PM, Stephanie Lewis wrote:
>> I can do this.
>> -- Stephanie Lewis
>> On Jul 26, 2010, at 5:57 AM, Adam Barth wrote:
>>> Would someone from Apple be willing to run the patch below though the
>>> PLT? We're doing well on our parsing benchmark (4% speedup), but the
>>> PLT might have a different mix of HTML.
>>> diff --git a/WebCore/html/HTMLTreeBuilder.cpp b/WebCore/html/HTMLTreeBuilder.cpp
>>> index 7a9c295..5b89c37 100644
>>> --- a/WebCore/html/HTMLTreeBuilder.cpp
>>> +++ b/WebCore/html/HTMLTreeBuilder.cpp
>>> @@ -327,7 +327,7 @@ HTMLTreeBuilder::HTMLTreeBuilder(HTMLTokenizer*
>>> tokenizer, HTMLDocument* documen
>>> , m_originalInsertionMode(InitialMode)
>>> , m_secondaryInsertionMode(InitialMode)
>>> , m_tokenizer(tokenizer)
>>> - , m_legacyTreeBuilder(shouldUseLegacyTreeBuilder(document) ? new
>>> LegacyHTMLTreeBuilder(document, reportErrors) : 0)
>>> + , m_legacyTreeBuilder(0)
>>> , m_lastScriptElementStartLine(uninitializedLineNumberValue)
>>> , m_scriptToProcessStartLine(uninitializedLineNumberValue)
>>> , m_fragmentScriptingPermission(FragmentScriptingAllowed)
>>> On Thu, Jul 22, 2010 at 3:30 AM, Adam Barth <abarth at webkit.org> wrote:
>>>> We're getting close to enabling the HTML5 tree builder on trunk. Once
>>>> we do that, we'll have the core of the HTML5 parsing algorithm turned
>>>> on, including SVG-in-HTML. There are still a bunch of details left to
>>>> finish (such as fragment parsing, MathML entities, and better error
>>>> reporting), but this marks a significant milestone for this work.
>>>> The tree builder is markedly more complicated than the tokenizer, and
>>>> I'm sure we're going to have some bad regressions. I'd like to ask
>>>> your patience and your help to spot and triage these regressions.
>>>> We've gotten about as much mileage as we can out of the HTML5lib test
>>>> suite and the LayoutTests. The next step for is to see how the
>>>> algorithm works in the real world.
>>>> There are about 84 tests that will require new expectations, mostly
>>>> due to invisible differences in render tree dumps (e.g., one more or
>>>> fewer 0x0 render text). In about half the cases, we've manually
>>>> verified that our new results agree with the Firefox nightly builds,
>>>> which is great from a compliance and interoperability point of view.
>>>> The other half involve things like the exact text for the <isindex>,
>>>> which we've chosen to match the spec exactly, or the <keygen> element,
>>>> which needs some shadow DOM love to hide its implementation details
>>>> from web content.
>>>> As for performance, last time we ran our parser benchmark, the new
>>>> tree builder was 1% faster than the old tree builder. There's still a
>>>> bunch of low-hanging performance work we can do, such as atomizing
>>>> strings and inlining functions. If you're interested in performance,
>>>> let me or Eric know and we can point you in the right direction.
>>>> I don't have an exact timeline for when we're going to throw the
>>>> switch, but sometime in the next few days. If you'd like us to hold
>>>> off for any reason, please let Eric or me know.
>>>> P.S., you can follow along by CCing yourself on the master bug,
>>>> <https://bugs.webkit.org/show_bug.cgi?id=41123>, or by looking at our
>>>> LayoutTest failure triage spreadsheet,
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