Changeset 128146 in webkit for trunk/Source/JavaScriptCore/runtime/JSCell.h

Timestamp:

Sep 10, 2012, 10:05:53 PM (13 years ago)

Author:

[email protected]

Message:

Remove m_classInfo from JSCell
​https://bugs.webkit.org/show_bug.cgi?id=96311

Reviewed by Oliver Hunt.

Now that no one is using the ClassInfo in JSCell, we can remove it for the greater good. This is a 1.5% win on v8v7 and
a 1.7% win on kraken, and is an overall performance progression.

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::emitAllocateBasicJSObject): Had to rearrange the order of when we take things off the free list
and when we store the Structure in the object because we would clobber the free list otherwise. This made it not okay for
the structure argument and the scratch register to alias one another. Also removed the store of the ClassInfo pointer in the
object. Yay!
(SpeculativeJIT):

• dfg/DFGSpeculativeJIT32_64.cpp: Since it's no longer okay for for the scratch register and structure register to alias

one another as stated above, had to add an extra temporary for passing the Structure.
(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT64.cpp: Ditto.

(JSC::DFG::SpeculativeJIT::compile):

• jit/JITInlineMethods.h:

(JSC::JIT::emitAllocateBasicJSObject): Similar changes to DFG's inline allocation except that it removed the object from
the free list first, so no changes were necessary there.

• llint/LowLevelInterpreter.asm: Change the constants for amount of inline storage to match PropertyOffset.h and remove

the store of the ClassInfo pointer during inline allocation.

• llint/LowLevelInterpreter32_64.asm:
• llint/LowLevelInterpreter64.asm:
• runtime/JSCell.h: Remove the m_classInfo field and associated methods.

(JSCell):

• runtime/JSObject.h:

(JSObject):

• runtime/PropertyOffset.h: Expand the number of inline storage properties to take up the extra space that we're freeing

with the removal of the ClassInfo pointer.
(JSC):

• runtime/Structure.h:

(JSC):
(JSC::JSCell::JSCell):
(JSC::JSCell::finishCreation):

File:

• trunk/Source/JavaScriptCore/runtime/JSCell.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/runtime/JSCell.h

@@ -110 +110 @@
         // Object operations, with the toObject operation included.
         const ClassInfo* classInfo() const;
-        const ClassInfo* validatedClassInfo() const;
         const MethodTable* methodTable() const;
         static void put(JSCell*, ExecState*, PropertyName, JSValue, PutPropertySlot&);
@@ -135 +134 @@
         }
 
-        static ptrdiff_t classInfoOffset()
-        {
-            return OBJECT_OFFSETOF(JSCell, m_classInfo);
-        }
-        
         void* structureAddress()
         {
@@ -172 +166 @@
         friend class LLIntOffsetsExtractor;
         
-        const ClassInfo* m_classInfo;
         WriteBarrier<Structure> m_structure;
     };