Changeset 36032 in webkit for trunk/JavaScriptCore/kjs/StructureID.cpp

Timestamp:

Sep 2, 2008, 7:31:45 PM (17 years ago)

Author:

[email protected]

Message:

JavaScriptCore:

2008-09-02 Geoffrey Garen <​[email protected]>

Reviewed by Sam Weinig.

Implemented the rest of Darin's review comments for the 09-01 inline
caching patch.

SunSpider says 0.5% faster, but that seems like noise.

• JavaScriptCore.xcodeproj/project.pbxproj: Put PutPropertySlot into its own file, and added BatchedTransitionOptimizer.

• VM/CodeBlock.cpp: (KJS::CodeBlock::~CodeBlock): Use array indexing instead of a pointer iterator.

• VM/CodeGenerator.cpp: (KJS::CodeGenerator::CodeGenerator): Used BatchedTransitionOptimizer to make batched put and remove for declared variables fast, without forever pessimizing the global object. Removed the old getDirect/removeDirect hack that tried to do the same in a more limited way.

• VM/CodeGenerator.h: Moved IdentifierRepHash to the KJS namespace since it doesn't specialize anything in WTF.

• VM/Machine.cpp: (KJS::Machine::Machine): Nixed the DummyConstruct tag because it was confusingly named.

(KJS::Machine::execute): Used BatchedTransitionOptimizer, as above. Fixed
up some comments.

(KJS::cachePrototypeChain): Cast to JSObject*, since it's more specific.

(KJS::Machine::tryCachePutByID): Use isNull() instead of comparing to
jsNull(), since isNull() leaves more options open for the future.
(KJS::Machine::tryCacheGetByID): ditto
(KJS::Machine::privateExecute): ditto

• VM/SamplingTool.cpp: (KJS::SamplingTool::dump): Use C++-style cast, to match our style guidelines.

• kjs/BatchedTransitionOptimizer.h: Added. New class that allows host code to add a batch of properties to an object in an efficient way.

• kjs/JSActivation.cpp: Use isNull(), as above.

• kjs/JSArray.cpp: Get rid of DummyConstruct tag, as above.
• kjs/JSArray.h:

• kjs/JSGlobalData.cpp: Nixed two unused StructureIDs.
• kjs/JSGlobalData.h:

• kjs/JSImmediate.cpp: Use isNull(), as above.

• kjs/JSObject.cpp: (KJS::JSObject::mark): Moved mark tracing code elsewhere, to make this function more readable.

(KJS::JSObject::put): Use isNull(), as above.

(KJS::JSObject::createInheritorID): Return a raw pointer, since the
object is owned by a data member, not necessarily the caller.

• kjs/JSObject.h:

• kjs/JSString.cpp: Use isNull(), as above.

• kjs/PropertyMap.h: Updated to use PropertySlot::invalidOffset.

• kjs/PropertySlot.h: Changed KJS_INVALID_OFFSET to WTF::notFound because C macros are so 80's.

• kjs/PutPropertySlot.h: Added. Split out of PropertySlot.h. Also renamed PutPropertySlot::SlotType to PutPropertySlot::Type, and slotBase to base, since "slot" was redundant.

• kjs/StructureID.cpp: Added a new transition *away* from dictionary status, to support BatchedTransitionOptimizer.

(KJS::StructureIDChain::StructureIDChain): No need to store m_size as
a data member, so keep it in a local, which might be faster.

• kjs/StructureID.h:

• kjs/SymbolTable.h: Moved IdentifierRepHash to KJS namespace, as above.
• kjs/ustring.h:

JavaScriptGlue:

2008-09-02 Geoffrey Garen <​[email protected]>

Reviewed by Sam Weinig.

Implemented the rest of Darin's review comments for the 09-01 inline
caching patch.

• ForwardingHeaders/kjs/PutPropertySlot.h: Added.

File:

• trunk/JavaScriptCore/kjs/StructureID.cpp (modified) (5 diffs)

trunk/JavaScriptCore/kjs/StructureID.cpp

@@ -29 +29 @@
 
 #include "identifier.h"
-#include "JSCell.h"
+#include "JSObject.h"
 #include <wtf/RefPtr.h>
 
@@ -54 +54 @@
 
     if (structureID->m_transitionCount > s_maxTransitionLength)
-        return dictionaryTransition(structureID);
+        return toDictionaryTransition(structureID);
 
     RefPtr<StructureID> transition = create(structureID->m_prototype);
@@ -66 +66 @@
 }
 
-PassRefPtr<StructureID> StructureID::dictionaryTransition(StructureID* structureID)
+PassRefPtr<StructureID> StructureID::toDictionaryTransition(StructureID* structureID)
 {
     ASSERT(!structureID->m_isDictionary);
@@ -72 +72 @@
     RefPtr<StructureID> transition = create(structureID->m_prototype);
     transition->m_isDictionary = true;
-    transition->m_transitionCount = structureID->m_transitionCount + 1;
     return transition.release();
+}
+
+PassRefPtr<StructureID> StructureID::fromDictionaryTransition(StructureID* structureID)
+{
+    ASSERT(structureID->m_isDictionary);
+
+    // Since dictionary StructureIDs are not shared, and no opcodes specialize
+    // for them, we don't need to allocate a new StructureID when transitioning
+    // to non-dictionary status.
+    structureID->m_isDictionary = false;
+    return structureID;
 }
 
@@ -99 +109 @@
 
 StructureIDChain::StructureIDChain(StructureID* structureID)
-    : m_size(0)
 {
+    size_t size = 0;
+
     StructureID* tmp = structureID;
-    while (tmp->prototype() != jsNull()) {
-        ++m_size;
+    while (!tmp->prototype()->isNull()) {
+        ++size;
         tmp = static_cast<JSCell*>(tmp->prototype())->structureID();
     }
 
-    m_vector.set(new RefPtr<StructureID>[m_size]);
+    m_vector.set(new RefPtr<StructureID>[size]);
 
-    for (size_t i = 0; i < m_size; ++i) {
+    for (size_t i = 0; i < size; ++i) {
         m_vector[i] = structureID;
-        structureID = static_cast<JSCell*>(structureID->prototype())->structureID();
+        structureID = static_cast<JSObject*>(structureID->prototype())->structureID();
     }
 }