Changeset 52856 in webkit for trunk/JavaScriptCore/runtime/UStringImpl.h

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/UStringImpl.h (modified) (7 diffs)

trunk/JavaScriptCore/runtime/UStringImpl.h

@@ -138 +138 @@
     unsigned computedHash() const { ASSERT(m_hash); return m_hash; } // fast path for Identifiers
     void setHash(unsigned hash) { ASSERT(hash == computeHash(data(), m_length)); m_hash = hash; } // fast path for Identifiers
-    bool isIdentifier() const { return m_identifierTable; }
-    IdentifierTable* identifierTable() const { return m_identifierTable; }
-    void setIdentifierTable(IdentifierTable* table) { ASSERT(!isStatic()); m_identifierTable = table; }
+    bool isIdentifier() const { return m_isIdentifier; }
+    void setIsIdentifier(bool isIdentifier) { m_isIdentifier = isIdentifier; }
 
     UStringImpl* ref() { m_refCount += s_refCountIncrement; return this; }
@@ -174 +173 @@
         ASSERT(bufferOwnerString()->bufferOwnership() != BufferSubstring);
         // Static strings cannot be put in identifier tables, because they are globally shared.
-        ASSERT(!isStatic() || !identifierTable());
+        ASSERT(!isStatic() || !isIdentifier());
     }
 
@@ -194 +193 @@
         , m_refCount(s_refCountIncrement)
         , m_hash(0)
-        , m_identifierTable(0)
+        , m_isIdentifier(false)
         , m_dataBuffer(0, ownership)
     {
@@ -210 +209 @@
         , m_refCount(s_staticRefCountInitialValue)
         , m_hash(0)
-        , m_identifierTable(0)
+        , m_isIdentifier(false)
         , m_dataBuffer(0, BufferOwned)
     {
@@ -222 +221 @@
         , m_refCount(s_refCountIncrement)
         , m_hash(0)
-        , m_identifierTable(0)
+        , m_isIdentifier(false)
         , m_dataBuffer(base.releaseRef(), BufferSubstring)
     {
@@ -239 +238 @@
         , m_refCount(s_refCountIncrement)
         , m_hash(0)
-        , m_identifierTable(0)
+        , m_isIdentifier(false)
         , m_dataBuffer(sharedBuffer.releaseRef(), BufferShared)
     {
@@ -269 +268 @@
     int m_length;
     unsigned m_refCount;
-    mutable unsigned m_hash;
-    IdentifierTable* m_identifierTable;
+    mutable unsigned m_hash : 31;
+    mutable unsigned m_isIdentifier : 1;
     UntypedPtrAndBitfield m_dataBuffer;