Changeset 55825 in webkit for trunk/JavaScriptCore/runtime/Identifier.cpp

Timestamp:

Mar 10, 2010, 6:36:08 PM (15 years ago)

Author:

[email protected]

Message:

​https://bugs.webkit.org/show_bug.cgi?id=35991
Would be faster to not use a thread specific to implement StringImpl::empty()

Reviewed by Darin Adler, Geoffrey Garen, Maciej Stachowiak.

JavaScriptCore:

Change JSC::UStringImpl's implementation of empty() match to match StringImpl's new implementation
(use a static defined within the empty() method), and change the interface to match too (return
a pointer not a reference).

~0% performance impact (possible minor progression from moving empty() from .h to .cpp).

• JavaScriptCore.exp:
• runtime/Identifier.cpp:

(JSC::Identifier::add):
(JSC::Identifier::addSlowCase):

• runtime/PropertyNameArray.cpp:

(JSC::PropertyNameArray::add):

• runtime/UString.cpp:

(JSC::initializeUString):
(JSC::UString::UString):

• runtime/UStringImpl.cpp:

(JSC::UStringImpl::empty):
(JSC::UStringImpl::create):

• runtime/UStringImpl.h:

(JSC::UStringImpl::adopt):
(JSC::UStringImpl::createUninitialized):
(JSC::UStringImpl::tryCreateUninitialized):

WebCore:

Copy JavaScriptCore in making 'static' strings threadsafe, make the empty string a static,
shared by all threads.

~2% progression on Dromaeo DOM core & JS lib tests.

• platform/ThreadGlobalData.cpp:

(WebCore::ThreadGlobalData::ThreadGlobalData):
(WebCore::ThreadGlobalData::~ThreadGlobalData):

• platform/ThreadGlobalData.h:

(WebCore::ThreadGlobalData::eventNames):

• platform/text/StringImpl.cpp:

(WebCore::StringImpl::StringImpl):
(WebCore::StringImpl::empty):

• platform/text/StringImpl.h:

(WebCore::StringImpl::deref):
(WebCore::StringImpl::hasOneRef):

File:

• trunk/JavaScriptCore/runtime/Identifier.cpp (modified) (3 diffs)

trunk/JavaScriptCore/runtime/Identifier.cpp

@@ -131 +131 @@
     }
     if (!c[0]) {
-        UString::Rep::empty().hash();
-        return &UString::Rep::empty();
+        UString::Rep::empty()->hash();
+        return UString::Rep::empty();
     }
     if (!c[1])
@@ -195 +195 @@
     }
     if (!length) {
-        UString::Rep::empty().hash();
-        return &UString::Rep::empty();
+        UString::Rep::empty()->hash();
+        return UString::Rep::empty();
     }
     UCharBuffer buf = {s, length}; 
@@ -226 +226 @@
     }
     if (!r->length()) {
-        UString::Rep::empty().hash();
-        return &UString::Rep::empty();
+        UString::Rep::empty()->hash();
+        return UString::Rep::empty();
     }
     return *globalData->identifierTable->add(r).first;