Bug 33878 – Add ThreadSpecific for for ENABLE(SINGLE_THREADED)

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Kwang Yul Seo]

When ENABLE(SINGLE_THREADED) is true, ThreadSpecific can be replaced with a simple getter/setter. 

Due to the change in https://bugs.webkit.org/show_bug.cgi?id=33236, an implementation of ThreadSpecific must be available to build WebKit. This causes a build failure for platforms without a proper ThreadSpecific implementation.

[Kwang Yul Seo]

Created attachment 46971 [details]
Implement ThreadSpecific with a simple getter/setter for ENABLE(SINGLE_THREADED)

[Eric Seidel (no email)]

I think Alexey is your best reviewer here.

[Alexey Proskuryakov]

The implementation looks fine, but I don't understand what ENABLE(SINGLE_THREADED) means. Is it about thread use in WebCore? If so, why do JSC-only changes made in bug 33236 make this patch necessary?

[Kwang Yul Seo]

ENABLE(SINGLE_THREADED) is used mainly by Qt port and it means both JavaScriptCore and WebCore are single-threaded. As ThreadSpecific can be used by both JavaScriptCore and WebCore, checking only ENABLE(JSC_MULTIPLE_THREADS) is not correct here.


Before 33236 is landed, ThreadSpecific was not used at all when some multi-threaded WebCore features such as database and workers are disabled. However, as the following code is added in 33236,  an implementation of ThreadSpecific is required even for single-threaded WebKit build.


#if ENABLE(JSC_MULTIPLE_THREADS)

pthread_once_t createIdentifierTableSpecificOnce = PTHREAD_ONCE_INIT;
static void createIdentifierTableSpecificCallback()
{
    ASSERT(!g_identifierTableSpecific);
    g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
}
void createIdentifierTableSpecific()
{
    pthread_once(&createIdentifierTableSpecificOnce, createIdentifierTableSpecificCallback);
    ASSERT(g_identifierTableSpecific);
}

#else

void createIdentifierTableSpecific()
{
    ASSERT(!g_identifierTableSpecific);
    g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
}

#endif

[Alexey Proskuryakov]

Comment on attachment 46971 [details]
Implement ThreadSpecific with a simple getter/setter for ENABLE(SINGLE_THREADED)

ok, r=me

[WebKit Commit Bot]

Comment on attachment 46971 [details]
Implement ThreadSpecific with a simple getter/setter for ENABLE(SINGLE_THREADED)

Clearing flags on attachment: 46971

Committed r53682: <http://trac.webkit.org/changeset/53682>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.