[webkit-dev] Enabling the HTML5 tree builder soon

Stephanie Lewis slewis at apple.com
Mon Jul 26 12:36:28 PDT 2010


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.
> 
> Thanks,
> Adam
> 
> 
> 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.
>> 
>> Adam
>> 
>> 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,
>> <https://spreadsheets.google.com/ccc?key=0AlC4tS7Ao1fIdEo0SFdLaVpiclBHMVNQcHlTenV5TEE&hl=en>.
>> 
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