Changeset 169815 in webkit for trunk/Source/JavaScriptCore/runtime/JSObject.h

Timestamp:

Jun 11, 2014, 11:40:13 AM (11 years ago)

Author:

[email protected]

Message:

Some JSValue::get() micro-optimzations.
<​https://webkit.org/b/133739>

Tighten some of the property lookup code to improve performance of the
eagerly reified prototype attributes:

• Instead of converting the property name to an integer at every step in the prototype chain, move that to a separate pass at the end since it should be a rare case.

• Cache the StructureIDTable in a local instead of fetching it from the Heap on every step.

• Make fillCustomGetterPropertySlot inline. It was out-of-lined based on the assumption that clients would mostly be cacheable GetByIds, and it gets pretty hot (~1%) in GetByVal.

• Pass the Structure directly to fillCustomGetterPropertySlot instead of refetching it from the StructureIDTable.

Reviewed by Geoff Garen.

• runtime/JSObject.cpp:

(JSC::JSObject::fillCustomGetterPropertySlot): Deleted.

• runtime/JSObject.h:

(JSC::JSObject::inlineGetOwnPropertySlot):
(JSC::JSObject::fillCustomGetterPropertySlot):
(JSC::JSObject::getOwnPropertySlot):
(JSC::JSObject::fastGetOwnPropertySlot):
(JSC::JSObject::getPropertySlot):
(JSC::JSObject::getOwnPropertySlotSlow): Deleted.

File:

• trunk/Source/JavaScriptCore/runtime/JSObject.h (modified) (8 diffs)

trunk/Source/JavaScriptCore/runtime/JSObject.h

@@ -32 +32 @@
 #include "CommonIdentifiers.h"
 #include "CopyWriteBarrier.h"
+#include "CustomGetterSetter.h"
 #include "DeferGC.h"
 #include "Heap.h"
@@ -958 +959 @@
     bool putDirectInternal(VM&, PropertyName, JSValue, unsigned attr, PutPropertySlot&, JSCell*);
 
-    bool inlineGetOwnPropertySlot(ExecState*, VM&, Structure&, PropertyName, PropertySlot&);
+    bool inlineGetOwnPropertySlot(VM&, Structure&, PropertyName, PropertySlot&);
     JS_EXPORT_PRIVATE void fillGetterPropertySlot(PropertySlot&, JSValue, unsigned, PropertyOffset);
-    JS_EXPORT_PRIVATE void fillCustomGetterPropertySlot(PropertySlot&, JSValue, unsigned);
+    void fillCustomGetterPropertySlot(PropertySlot&, JSValue, unsigned, Structure&);
 
     const HashTableValue* findPropertyHashEntry(VM&, PropertyName) const;
@@ -973 +974 @@
     unsigned getNewVectorLength(unsigned desiredLength);
 
-    bool getOwnPropertySlotSlow(ExecState*, PropertyName, PropertySlot&);
-        
     ArrayStorage* constructConvertedArrayStorageWithoutCopyingElements(VM&, unsigned neededLength);
         
@@ -1213 +1212 @@
 }
 
-ALWAYS_INLINE bool JSObject::inlineGetOwnPropertySlot(ExecState* exec, VM& vm, Structure& structure, PropertyName propertyName, PropertySlot& slot)
+ALWAYS_INLINE bool JSObject::inlineGetOwnPropertySlot(VM& vm, Structure& structure, PropertyName propertyName, PropertySlot& slot)
 {
     unsigned attributes;
     JSCell* specific;
     PropertyOffset offset = structure.get(vm, propertyName, attributes, specific);
-    if (LIKELY(isValidOffset(offset))) {
-        JSValue value = getDirect(offset);
-        if (structure.hasGetterSetterProperties() && value.isGetterSetter())
-            fillGetterPropertySlot(slot, value, attributes, offset);
-        else if (structure.hasCustomGetterSetterProperties() && value.isCustomGetterSetter())
-            fillCustomGetterPropertySlot(slot, value, attributes);
-        else
-            slot.setValue(this, attributes, value, offset);
-        return true;
-    }
-
-    return getOwnPropertySlotSlow(exec, propertyName, slot);
-}
-
-inline bool JSObject::getOwnPropertySlotSlow(ExecState* exec, PropertyName propertyName, PropertySlot& slot)
-{
-    unsigned i = propertyName.asIndex();
-    if (i != PropertyName::NotAnIndex)
-        return getOwnPropertySlotByIndex(this, exec, i, slot);
-    return false;
+    if (!isValidOffset(offset))
+        return false;
+
+    JSValue value = getDirect(offset);
+    if (structure.hasGetterSetterProperties() && value.isGetterSetter())
+        fillGetterPropertySlot(slot, value, attributes, offset);
+    else if (structure.hasCustomGetterSetterProperties() && value.isCustomGetterSetter())
+        fillCustomGetterPropertySlot(slot, value, attributes, structure);
+    else
+        slot.setValue(this, attributes, value, offset);
+
+    return true;
+}
+
+ALWAYS_INLINE void JSObject::fillCustomGetterPropertySlot(PropertySlot& slot, JSValue customGetterSetter, unsigned attributes, Structure& structure)
+{
+    if (structure.isDictionary()) {
+        slot.setCustom(this, attributes, jsCast<CustomGetterSetter*>(customGetterSetter)->getter());
+        return;
+    }
+    slot.setCacheableCustom(this, attributes, jsCast<CustomGetterSetter*>(customGetterSetter)->getter());
 }
 
@@ -1247 +1247 @@
     VM& vm = exec->vm();
     Structure& structure = *object->structure(vm);
-    return object->inlineGetOwnPropertySlot(exec, vm, structure, propertyName, slot);
+    if (object->inlineGetOwnPropertySlot(vm, structure, propertyName, slot))
+        return true;
+    unsigned index = propertyName.asIndex();
+    if (index != PropertyName::NotAnIndex)
+        return getOwnPropertySlotByIndex(object, exec, index, slot);
+    return false;
 }
 
@@ -1253 +1258 @@
 {
     if (!TypeInfo::overridesGetOwnPropertySlot(inlineTypeFlags()))
-        return asObject(this)->inlineGetOwnPropertySlot(exec, vm, structure, propertyName, slot);
+        return asObject(this)->inlineGetOwnPropertySlot(vm, structure, propertyName, slot);
     return structure.classInfo()->methodTable.getOwnPropertySlot(this, exec, propertyName, slot);
 }
@@ -1262 +1267 @@
 {
     VM& vm = exec->vm();
+    auto& structureIDTable = vm.heap.structureIDTable();
     JSObject* object = this;
     while (true) {
-        Structure& structure = *object->structure(vm);
+        Structure& structure = *structureIDTable.get(object->structureID());
         if (object->fastGetOwnPropertySlot(exec, vm, structure, propertyName, slot))
             return true;
         JSValue prototype = structure.storedPrototype();
         if (!prototype.isObject())
-            return false;
+            break;
         object = asObject(prototype);
     }
+
+    unsigned index = propertyName.asIndex();
+    if (index != PropertyName::NotAnIndex)
+        return getPropertySlot(exec, index, slot);
+    return false;
 }
 
@@ -1277 +1288 @@
 {
     VM& vm = exec->vm();
+    auto& structureIDTable = vm.heap.structureIDTable();
     JSObject* object = this;
     while (true) {
-        Structure& structure = *object->structure(vm);
+        Structure& structure = *structureIDTable.get(object->structureID());
         if (structure.classInfo()->methodTable.getOwnPropertySlotByIndex(object, exec, propertyName, slot))
             return true;