Changeset 52856 in webkit for trunk/JavaScriptCore/runtime/Identifier.cpp

Timestamp:

Jan 6, 2010, 11:33:29 AM (15 years ago)

Author:

[email protected]

Message:

​https://bugs.webkit.org/show_bug.cgi?id=33236
Remove m_identifierTable pointer from UString

Reviewed by Sam Weinig.

JavaScriptCore:

Currently every string holds a pointer so that during destruction,
if a string has been used as an identifier, it can remove itself
from the table. By instead accessing the identifierTable via a
thread specific tracking the table associated with the current
globaldata, we can save the memory cost of this pointer.

• API/APIShims.h:

(JSC::APIEntryShimWithoutLock::APIEntryShimWithoutLock):
(JSC::APIEntryShimWithoutLock::~APIEntryShimWithoutLock):
(JSC::APICallbackShim::APICallbackShim):
(JSC::APICallbackShim::~APICallbackShim):

• change the API shims to track the identifierTable of the current JSGlobalData.

• API/JSContextRef.cpp:

(JSContextGroupCreate):

• update creation of JSGlobalData for API usage to use new create method.
• fix shim instanciation bug in JSGlobalContextCreateInGroup.

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

(JSC::checkSyntax):
(JSC::evaluate):

• add asserts to check the identifierTable is being tracked correctly.

• runtime/Identifier.cpp:

(JSC::IdentifierTable::~IdentifierTable):
(JSC::IdentifierTable::add):
(JSC::Identifier::remove):
(JSC::Identifier::checkSameIdentifierTable):
(JSC::createIdentifierTableSpecificCallback):
(JSC::createIdentifierTableSpecific):
(JSC::createDefaultDataSpecific):

• Use currentIdentifierTable() instead of UStringImpl::m_identifierTable.
• Define methods to access the thread specific identifier tables.

• runtime/Identifier.h:

(JSC::ThreadIdentifierTableData::ThreadIdentifierTableData):
(JSC::defaultIdentifierTable):
(JSC::setDefaultIdentifierTable):
(JSC::currentIdentifierTable):
(JSC::setCurrentIdentifierTable):
(JSC::resetCurrentIdentifierTable):

• Declare methods to access the thread specific identifier tables.

• runtime/JSGlobalData.cpp:

(JSC::JSGlobalData::createNonDefault):
(JSC::JSGlobalData::create):
(JSC::JSGlobalData::sharedInstance):

• creation of JSGlobalData objects, other than for API usage, associate themselves with the current thread.

• runtime/JSGlobalData.h:
• runtime/UStringImpl.cpp:

(JSC::UStringImpl::destroy):

• destroy() method should be using isIdentifier().

• runtime/UStringImpl.h:

(JSC::UStringImpl::isIdentifier):
(JSC::UStringImpl::setIsIdentifier):
(JSC::UStringImpl::checkConsistency):
(JSC::UStringImpl::UStringImpl):

• replace m_identifierTable with a single m_isIdentifier bit.

• wtf/StringHashFunctions.h:

(WTF::stringHash):

• change string hash result from 32-bit to 31-bit, to free a bit in UStringImpl for m_isIdentifier.

JavaScriptGlue:

Add API shims similar to those used in the JSC API to track the current identifierTable.

• JSBase.cpp:

(JSBase::Release):

• JSUtils.cpp:

(JSObjectKJSValue):
(KJSValueToCFTypeInternal):
(unprotectGlobalObject):
(JSGlueAPIEntry::JSGlueAPIEntry):
(JSGlueAPIEntry::~JSGlueAPIEntry):
(JSGlueAPICallback::JSGlueAPICallback):
(JSGlueAPICallback::~JSGlueAPICallback):

• JSUtils.h:
• JSValueWrapper.cpp:

(JSValueWrapper::JSObjectCopyPropertyNames):
(JSValueWrapper::JSObjectCopyProperty):
(JSValueWrapper::JSObjectSetProperty):
(JSValueWrapper::JSObjectCallFunction):
(JSValueWrapper::JSObjectCopyCFValue):

• JavaScriptGlue.cpp:

(JSRunCreate):
(JSRunEvaluate):
(JSRunCheckSyntax):
(JSCollect):

• JavaScriptGlue.xcodeproj/project.pbxproj:
• UserObjectImp.cpp:

(UserObjectImp::callAsFunction):

File:

• trunk/JavaScriptCore/runtime/Identifier.cpp (modified) (6 diffs)

trunk/JavaScriptCore/runtime/Identifier.cpp

@@ -29 +29 @@
 #include <wtf/HashSet.h>
 
+using WTF::ThreadSpecific;
+
 namespace JSC {
 
@@ -39 +41 @@
         HashSet<UString::Rep*>::iterator end = m_table.end();
         for (HashSet<UString::Rep*>::iterator iter = m_table.begin(); iter != end; ++iter)
-            (*iter)->setIdentifierTable(0);
+            (*iter)->setIsIdentifier(false);
     }
     
@@ -45 +47 @@
     {
         std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add(value);
-        (*result.first)->setIdentifierTable(this);
+        (*result.first)->setIsIdentifier(true);
         return result;
     }
@@ -53 +55 @@
     {
         std::pair<HashSet<UString::Rep*>::iterator, bool> result = m_table.add<U, V>(value);
-        (*result.first)->setIdentifierTable(this);
+        (*result.first)->setIsIdentifier(true);
         return result;
     }
@@ -239 +241 @@
 void Identifier::remove(UString::Rep* r)
 {
-    r->identifierTable()->remove(r);
+    currentIdentifierTable()->remove(r);
 }
 
 #ifndef NDEBUG
 
-void Identifier::checkSameIdentifierTable(ExecState* exec, UString::Rep* rep)
-{
-    ASSERT(rep->identifierTable() == exec->globalData().identifierTable);
-}
-
-void Identifier::checkSameIdentifierTable(JSGlobalData* globalData, UString::Rep* rep)
-{
-    ASSERT(rep->identifierTable() == globalData->identifierTable);
+void Identifier::checkSameIdentifierTable(ExecState* exec, UString::Rep*)
+{
+    ASSERT(exec->globalData().identifierTable == currentIdentifierTable());
+}
+
+void Identifier::checkSameIdentifierTable(JSGlobalData* globalData, UString::Rep*)
+{
+    ASSERT(globalData->identifierTable == currentIdentifierTable());
 }
 
@@ -266 +268 @@
 #endif
 
+ThreadSpecific<ThreadIdentifierTableData>* g_identifierTableSpecific = 0;
+
+#if ENABLE(JSC_MULTIPLE_THREADS)
+
+pthread_once_t createIdentifierTableSpecificOnce = PTHREAD_ONCE_INIT;
+void createIdentifierTableSpecificCallback()
+{
+    ASSERT(!g_identifierTableSpecific);
+    g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
+}
+void createIdentifierTableSpecific()
+{
+    pthread_once(&createIdentifierTableSpecificOnce, createIdentifierTableSpecificCallback);
+    ASSERT(g_identifierTableSpecific);
+}
+
+#else 
+
+void createDefaultDataSpecific()
+{
+    ASSERT(!g_identifierTableSpecific);
+    g_identifierTableSpecific = new ThreadSpecific<ThreadIdentifierTableData>();
+}
+
+#endif
+
 } // namespace JSC