Changeset 78732 in webkit for trunk/Source/JavaScriptCore/runtime/JSObject.cpp

Timestamp:

Feb 16, 2011, 1:35:19 PM (14 years ago)

Author:

[email protected]

Message:

Bug 54524 - Allow JSObject to fully utilize cell's capacity for inline storage.

Reviewed by Geoff Garen.

Currently JSObject is both directly instantiated for regular JS objects, and
derived to implement subtypes. A consequence of this is that we need to ensure
that sufficient space from the cell is left unused and available for any data
members that will be introduced by subclasses of JSObject. By restructuring
the internal storage array out of JSObject we can increase the size in the
internal storage for regular objects.

Add classes JSFinalObject and JSNonFinalObject. JSNonFinalObject retains as
much additional capacity as is currently available to allow for data members
in subclasses. JSFinalObject utilizes all available space for internal storage,
and only allows construction through JSFinalObject::create().

Source/JavaScriptCore:

The additional storage made available in the JSObject means that we need no
longer rely on a union of the internal storage with a pointer to storage that
is only valid for external storage. This means we can go back to always having
a valid pointer to property storage, regardless of whether this is internal or
external. This simplifies some cases of access to the array from C code, and
significantly simplifies JIT access, since repatching no longer needs to be
able to change between a load of the storage pointer / a LEA of the internal
storage.

• API/JSObjectRef.cpp:

(JSObjectMake):

• assembler/ARMAssembler.h:
• assembler/ARMv7Assembler.h:
• assembler/AbstractMacroAssembler.h:

(JSC::AbstractMacroAssembler::repatchPointer):

• assembler/MIPSAssembler.h:
• assembler/MacroAssemblerARM.h:
• assembler/MacroAssemblerARMv7.h:
• assembler/MacroAssemblerMIPS.h:
• assembler/MacroAssemblerX86.h:
• assembler/MacroAssemblerX86_64.h:
• assembler/RepatchBuffer.h:
• assembler/X86Assembler.h:
• debugger/DebuggerActivation.cpp:

(JSC::DebuggerActivation::DebuggerActivation):

• debugger/DebuggerActivation.h:
• interpreter/Interpreter.cpp:

(JSC::Interpreter::privateExecute):

• jit/JIT.h:
• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_resolve_global):

• jit/JITOpcodes32_64.cpp:

(JSC::JIT::emit_op_resolve_global):

• jit/JITPropertyAccess.cpp:

(JSC::JIT::compileGetDirectOffset):
(JSC::JIT::emit_op_get_by_pname):
(JSC::JIT::compileGetByIdHotPath):
(JSC::JIT::emit_op_put_by_id):
(JSC::JIT::compilePutDirectOffset):
(JSC::JIT::patchGetByIdSelf):
(JSC::JIT::patchPutByIdReplace):
(JSC::JIT::privateCompileGetByIdProto):
(JSC::JIT::privateCompileGetByIdSelfList):
(JSC::JIT::privateCompileGetByIdProtoList):
(JSC::JIT::privateCompileGetByIdChainList):
(JSC::JIT::privateCompileGetByIdChain):

• jit/JITPropertyAccess32_64.cpp:

(JSC::JIT::compileGetByIdHotPath):
(JSC::JIT::emit_op_put_by_id):
(JSC::JIT::compilePutDirectOffset):
(JSC::JIT::compileGetDirectOffset):
(JSC::JIT::patchGetByIdSelf):
(JSC::JIT::patchPutByIdReplace):
(JSC::JIT::privateCompileGetByIdProto):
(JSC::JIT::privateCompileGetByIdSelfList):
(JSC::JIT::privateCompileGetByIdProtoList):
(JSC::JIT::privateCompileGetByIdChainList):
(JSC::JIT::privateCompileGetByIdChain):
(JSC::JIT::emit_op_get_by_pname):

• jit/JITStubs.cpp:

(JSC::DEFINE_STUB_FUNCTION):

• runtime/Arguments.h:

(JSC::Arguments::Arguments):

• runtime/ErrorInstance.cpp:

(JSC::ErrorInstance::ErrorInstance):

• runtime/ErrorInstance.h:
• runtime/ExceptionHelpers.cpp:

(JSC::InterruptedExecutionError::InterruptedExecutionError):
(JSC::TerminatedExecutionError::TerminatedExecutionError):

• runtime/JSArray.cpp:

(JSC::JSArray::JSArray):

• runtime/JSArray.h:
• runtime/JSByteArray.cpp:

(JSC::JSByteArray::JSByteArray):

• runtime/JSByteArray.h:

(JSC::JSByteArray::JSByteArray):

• runtime/JSFunction.cpp:

(JSC::JSFunction::getOwnPropertySlot):

• runtime/JSGlobalData.cpp:

(JSC::JSGlobalData::JSGlobalData):

• runtime/JSGlobalObject.h:

(JSC::constructEmptyObject):

• runtime/JSNotAnObject.h:

(JSC::JSNotAnObject::JSNotAnObject):

• runtime/JSObject.cpp:

(JSC::JSObject::createInheritorID):
(JSC::JSObject::allocatePropertyStorage):

• runtime/JSObject.h:

(JSC::JSObject::propertyStorage):
(JSC::JSNonFinalObject::JSNonFinalObject):
(JSC::JSNonFinalObject::createStructure):
(JSC::JSFinalObject::create):
(JSC::JSFinalObject::createStructure):
(JSC::JSFinalObject::JSFinalObject):
(JSC::JSObject::offsetOfInlineStorage):
(JSC::constructEmptyObject):
(JSC::createEmptyObjectStructure):
(JSC::JSObject::JSObject):
(JSC::JSObject::~JSObject):
(JSC::Structure::isUsingInlineStorage):

• runtime/JSObjectWithGlobalObject.cpp:

(JSC::JSObjectWithGlobalObject::JSObjectWithGlobalObject):

• runtime/JSObjectWithGlobalObject.h:

(JSC::JSObjectWithGlobalObject::JSObjectWithGlobalObject):

• runtime/JSTypeInfo.h:

(JSC::TypeInfo::TypeInfo):
(JSC::TypeInfo::isVanilla):

• runtime/JSVariableObject.h:

(JSC::JSVariableObject::JSVariableObject):

• runtime/JSWrapperObject.h:

(JSC::JSWrapperObject::JSWrapperObject):

• runtime/ObjectConstructor.cpp:

(JSC::constructObject):

• runtime/ObjectPrototype.cpp:

(JSC::ObjectPrototype::ObjectPrototype):

• runtime/ObjectPrototype.h:
• runtime/StrictEvalActivation.cpp:

(JSC::StrictEvalActivation::StrictEvalActivation):

• runtime/StrictEvalActivation.h:
• runtime/Structure.cpp:

(JSC::Structure::Structure):
(JSC::Structure::growPropertyStorageCapacity):

Source/JavaScriptGlue:

• UserObjectImp.cpp:
• UserObjectImp.h:

Update JSObject -> JSNonFinalObject.

Source/WebCore:

• bindings/js/JSDOMWindowShell.h:

Update JSObject -> JSNonFinalObject.

File:

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

trunk/Source/JavaScriptCore/runtime/JSObject.cpp

@@ -43 +43 @@
 
 ASSERT_CLASS_FITS_IN_CELL(JSObject);
+ASSERT_CLASS_FITS_IN_CELL(JSNonFinalObject);
+ASSERT_CLASS_FILLS_CELL(JSFinalObject);
 
 const char* StrictModeReadonlyPropertyWriteError = "Attempted to assign to readonly property.";
@@ -556 +558 @@
 Structure* JSObject::createInheritorID()
 {
-    m_inheritorID = JSObject::createStructure(this);
+    m_inheritorID = createEmptyObjectStructure(this);
     return m_inheritorID.get();
 }
@@ -562 +564 @@
 void JSObject::allocatePropertyStorage(size_t oldSize, size_t newSize)
 {
-    allocatePropertyStorageInline(oldSize, newSize);
+    ASSERT(newSize > oldSize);
+
+    // It's important that this function not rely on m_structure, since
+    // we might be in the middle of a transition.
+    bool wasInline = (oldSize < JSObject::baseExternalStorageCapacity);
+
+    PropertyStorage oldPropertyStorage = m_propertyStorage;
+    PropertyStorage newPropertyStorage = new WriteBarrierBase<Unknown>[newSize];
+
+    for (unsigned i = 0; i < oldSize; ++i)
+       newPropertyStorage[i] = oldPropertyStorage[i];
+
+    if (!wasInline)
+        delete [] oldPropertyStorage;
+
+    m_propertyStorage = newPropertyStorage;
 }