Changeset 128265 in webkit for trunk/Source/JavaScriptCore/runtime/JSFunction.cpp

Timestamp:

Sep 11, 2012, 11:14:56 PM (13 years ago)

Author:

[email protected]

Message:

Don't allocate a backing store just for a function's name
​https://bugs.webkit.org/show_bug.cgi?id=96468

Reviewed by Oliver Hunt.

Treat function.name like function.length etc., and use a custom getter.
This saves space in closures.

• debugger/DebuggerCallFrame.cpp:

(JSC::DebuggerCallFrame::functionName):

• debugger/DebuggerCallFrame.h:

(DebuggerCallFrame): Updated for interface change.

• runtime/Executable.h:

(JSC::JSFunction::JSFunction): Do a little inlining.

• runtime/JSFunction.cpp:

(JSC::JSFunction::finishCreation): Gone now. That's the point of the patch.

(JSC::JSFunction::name):
(JSC::JSFunction::displayName):
(JSC::JSFunction::nameGetter):
(JSC::JSFunction::getOwnPropertySlot):
(JSC::JSFunction::getOwnPropertyDescriptor):
(JSC::JSFunction::getOwnPropertyNames):
(JSC::JSFunction::put):
(JSC::JSFunction::deleteProperty):
(JSC::JSFunction::defineOwnProperty): Added custom accessors for .name
just like .length and others.

• runtime/JSFunction.h:

(JSC::JSFunction::create):
(JSFunction): Updated for interface changes.

File:

• trunk/Source/JavaScriptCore/runtime/JSFunction.cpp (modified) (10 diffs)

trunk/Source/JavaScriptCore/runtime/JSFunction.cpp

@@ -85 +85 @@
 }
 
-JSFunction::JSFunction(ExecState* exec, FunctionExecutable* executable, JSScope* scope)
-    : Base(exec->globalData(), scope->globalObject()->functionStructure())
-    , m_executable(exec->globalData(), this, executable)
-    , m_scope(exec->globalData(), this, scope)
-{
-}
-
 void JSFunction::finishCreation(ExecState* exec, NativeExecutable* executable, int length, const String& name)
 {
@@ -99 +92 @@
     putDirect(exec->globalData(), exec->globalData().propertyNames->name, jsString(exec, name), DontDelete | ReadOnly | DontEnum);
     putDirect(exec->globalData(), exec->propertyNames().length, jsNumber(length), DontDelete | ReadOnly | DontEnum);
-}
-
-void JSFunction::finishCreation(ExecState* exec, FunctionExecutable* executable, JSScope* scope)
-{
-    JSGlobalData& globalData = exec->globalData();
-    Base::finishCreation(globalData);
-    ASSERT(inherits(&s_info));
-
-    // Switching the structure here is only safe if we currently have the function structure!
-    ASSERT(structure() == scope->globalObject()->functionStructure());
-    setStructureAndReallocateStorageIfNecessary(
-        globalData,
-        scope->globalObject()->namedFunctionStructure());
-    putDirectOffset(globalData, scope->globalObject()->functionNameOffset(), executable->nameValue());
 }
 
@@ -125 +104 @@
 }
 
-const String& JSFunction::name(ExecState* exec)
-{
-    return asString(getDirect(exec->globalData(), exec->globalData().propertyNames->name))->tryGetValue();
-}
-
-const String JSFunction::displayName(ExecState* exec)
+String JSFunction::name(ExecState* exec)
+{
+    return get(exec, exec->globalData().propertyNames->name).toWTFString(exec);
+}
+
+String JSFunction::displayName(ExecState* exec)
 {
     JSValue displayName = getDirect(exec->globalData(), exec->globalData().propertyNames->displayName);
@@ -214 +193 @@
 }
 
+JSValue JSFunction::nameGetter(ExecState*, JSValue slotBase, PropertyName)
+{
+    JSFunction* thisObj = jsCast<JSFunction*>(slotBase);
+    ASSERT(!thisObj->isHostFunction());
+    return thisObj->jsExecutable()->nameValue();
+}
+
 bool JSFunction::getOwnPropertySlot(JSCell* cell, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
 {
@@ -252 +238 @@
     }
 
+    if (propertyName == exec->propertyNames().name) {
+        slot.setCacheableCustom(thisObject, nameGetter);
+        return true;
+    }
+
     if (propertyName == exec->propertyNames().caller) {
         if (thisObject->jsExecutable()->isStrictMode()) {
@@ -300 +291 @@
     }
     
+    if (propertyName == exec->propertyNames().name) {
+        descriptor.setDescriptor(thisObject->jsExecutable()->nameValue(), ReadOnly | DontEnum | DontDelete);
+        return true;
+    }
+
     if (propertyName == exec->propertyNames().caller) {
         if (thisObject->jsExecutable()->isStrictMode()) {
@@ -328 +324 @@
         propertyNames.add(exec->propertyNames().caller);
         propertyNames.add(exec->propertyNames().length);
+        propertyNames.add(exec->propertyNames().name);
     }
     Base::getOwnPropertyNames(thisObject, exec, propertyNames, mode);
@@ -357 +354 @@
         return;
     }
-    if (propertyName == exec->propertyNames().arguments || propertyName == exec->propertyNames().length || propertyName == exec->propertyNames().caller) {
+    if (propertyName == exec->propertyNames().arguments || propertyName == exec->propertyNames().length || propertyName == exec->propertyNames().name || propertyName == exec->propertyNames().caller) {
         if (slot.isStrictMode())
             throwTypeError(exec, StrictModeReadonlyPropertyWriteError);
@@ -372 +369 @@
         && (propertyName == exec->propertyNames().arguments
             || propertyName == exec->propertyNames().length
+            || propertyName == exec->propertyNames().name
             || propertyName == exec->propertyNames().prototype
             || propertyName == exec->propertyNames().caller))
@@ -410 +408 @@
     } else if (propertyName == exec->propertyNames().length)
         valueCheck = !descriptor.value() || sameValue(exec, descriptor.value(), jsNumber(thisObject->jsExecutable()->parameterCount()));
+    else if (propertyName == exec->propertyNames().name)
+        valueCheck = !descriptor.value() || sameValue(exec, descriptor.value(), thisObject->jsExecutable()->nameValue());
     else
         return Base::defineOwnProperty(object, exec, propertyName, descriptor, throwException);