--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/SpillObjectCreator.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/SpillObjectCreator.java	Thu Oct 30 19:55:56 2014 +0100
@@ -88,7 +88,7 @@
                     final Property property = propertyMap.findProperty(key);
                     if (property != null) {
                         // normal property key
-                        property.setCurrentType(JSType.unboxedFieldType(constantValue));
+                        property.setType(JSType.unboxedFieldType(constantValue));
                         final int slot = property.getSlot();
                         if (!OBJECT_FIELDS_ONLY && constantValue instanceof Number) {
                             jpresetValues[slot] = ObjectClassGenerator.pack((Number)constantValue);

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/TypeEvaluator.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/TypeEvaluator.java	Thu Oct 30 19:55:56 2014 +0100
@@ -117,7 +117,7 @@
         }
 
         final Property property      = find.getProperty();
-        final Class<?> propertyClass = property.getCurrentType();
+        final Class<?> propertyClass = property.getType();
         if (propertyClass == null) {
             // propertyClass == null means its value is Undefined. It is probably not initialized yet, so we won't make
             // a type assumption yet.

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/objects/NativeObject.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/objects/NativeObject.java	Thu Oct 30 19:55:56 2014 +0100
@@ -672,7 +672,7 @@
             for (final Property prop : properties) {
                 if (prop.isEnumerable()) {
                     final Object value = sourceObj.get(prop.getKey());
-                    prop.setCurrentType(Object.class);
+                    prop.setType(Object.class);
                     prop.setValue(sourceObj, sourceObj, value, false);
                     propList.add(prop);
                 }

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/AccessorProperty.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/AccessorProperty.java	Thu Oct 30 19:55:56 2014 +0100
@@ -145,13 +145,6 @@
     transient MethodHandle objectSetter;
 
     /**
-     * Current type of this object, in object only mode, this is an Object.class. In dual-fields mode
-     * null means undefined, and primitive types are allowed. The reason a special type is used for
-     * undefined, is that are no bits left to represent it in primitive types
-     */
-    private Class<?> currentType;
-
-    /**
      * Delegate constructor for bound properties. This is used for properties created by
      * {@link ScriptRuntime#mergeScope} and the Nashorn {@code Object.bindProperties} method.
      * The former is used to add a script's defined globals to the current global scope while
@@ -171,7 +164,7 @@
         this.objectSetter    = bindTo(property.objectSetter, delegate);
         property.GETTER_CACHE = new MethodHandle[NOOF_TYPES];
         // Properties created this way are bound to a delegate
-        setCurrentType(property.getCurrentType());
+        setType(property.getType());
     }
 
     /**
@@ -248,7 +241,7 @@
         objectGetter  = getter.type() != Lookup.GET_OBJECT_TYPE ? MH.asType(getter, Lookup.GET_OBJECT_TYPE) : getter;
         objectSetter  = setter != null && setter.type() != Lookup.SET_OBJECT_TYPE ? MH.asType(setter, Lookup.SET_OBJECT_TYPE) : setter;
 
-        setCurrentType(OBJECT_FIELDS_ONLY ? Object.class : getterType);
+        setType(OBJECT_FIELDS_ONLY ? Object.class : getterType);
     }
 
     /**
@@ -317,7 +310,7 @@
      */
     public AccessorProperty(final String key, final int flags, final Class<?> structure, final int slot, final Class<?> initialType) {
         this(key, flags, structure, slot);
-        setCurrentType(OBJECT_FIELDS_ONLY ? Object.class : initialType);
+        setType(OBJECT_FIELDS_ONLY ? Object.class : initialType);
     }
 
     /**
@@ -330,13 +323,13 @@
     protected AccessorProperty(final AccessorProperty property, final Class<?> newType) {
         super(property, property.getFlags());
 
-        this.GETTER_CACHE    = newType != property.getCurrentType() ? new MethodHandle[NOOF_TYPES] : property.GETTER_CACHE;
+        this.GETTER_CACHE    = newType != property.getLocalType() ? new MethodHandle[NOOF_TYPES] : property.GETTER_CACHE;
         this.primitiveGetter = property.primitiveGetter;
         this.primitiveSetter = property.primitiveSetter;
         this.objectGetter    = property.objectGetter;
         this.objectSetter    = property.objectSetter;
 
-        setCurrentType(newType);
+        setType(newType);
     }
 
     /**
@@ -345,7 +338,7 @@
      * @param property  source property
      */
     protected AccessorProperty(final AccessorProperty property) {
-        this(property, property.getCurrentType());
+        this(property, property.getLocalType());
     }
 
     /**
@@ -354,7 +347,7 @@
      * @param initialValue initial value
      */
     protected final void setInitialValue(final ScriptObject owner, final Object initialValue) {
-        setCurrentType(JSType.unboxedFieldType(initialValue));
+        setType(JSType.unboxedFieldType(initialValue));
         if (initialValue instanceof Integer) {
             invokeSetter(owner, ((Integer)initialValue).intValue());
         } else if (initialValue instanceof Long) {
@@ -370,7 +363,7 @@
      * Initialize the type of a property
      */
     protected final void initializeType() {
-        setCurrentType(OBJECT_FIELDS_ONLY ? Object.class : null);
+        setType(OBJECT_FIELDS_ONLY ? Object.class : null);
     }
 
     private void readObject(final ObjectInputStream s) throws IOException, ClassNotFoundException {
@@ -557,12 +550,12 @@
         } else {
             getter = debug(
                 createGetter(
-                    getCurrentType(),
+                    getLocalType(),
                     type,
                     primitiveGetter,
                     objectGetter,
                     INVALID_PROGRAM_POINT),
-                getCurrentType(),
+                getLocalType(),
                 type,
                 "get");
             getterCache[i] = getter;
@@ -582,18 +575,18 @@
 
         return debug(
             createGetter(
-                getCurrentType(),
+                getLocalType(),
                 type,
                 primitiveGetter,
                 objectGetter,
                 programPoint),
-            getCurrentType(),
+            getLocalType(),
             type,
             "get");
     }
 
     private MethodHandle getOptimisticPrimitiveGetter(final Class<?> type, final int programPoint) {
-        final MethodHandle g = getGetter(getCurrentType());
+        final MethodHandle g = getGetter(getLocalType());
         return MH.asType(OptimisticReturnFilters.filterOptimisticReturnValue(g, type, programPoint), g.type().changeReturnType(type));
     }
 
@@ -631,7 +624,7 @@
     }
 
     private MethodHandle generateSetter(final Class<?> forType, final Class<?> type) {
-        return debug(createSetter(forType, type, primitiveSetter, objectSetter), getCurrentType(), type, "set");
+        return debug(createSetter(forType, type, primitiveSetter, objectSetter), getLocalType(), type, "set");
     }
 
     /**
@@ -639,7 +632,7 @@
      * @return true if undefined
      */
     protected final boolean isUndefined() {
-        return getCurrentType() == null;
+        return getLocalType() == null;
     }
 
     @Override
@@ -647,7 +640,7 @@
         checkUndeclared();
 
         final int typeIndex        = getAccessorTypeIndex(type);
-        final int currentTypeIndex = getAccessorTypeIndex(getCurrentType());
+        final int currentTypeIndex = getAccessorTypeIndex(getLocalType());
 
         //if we are asking for an object setter, but are still a primitive type, we might try to box it
         MethodHandle mh;
@@ -656,13 +649,13 @@
             final PropertyMap  newMap      = getWiderMap(currentMap, newProperty);
 
             final MethodHandle widerSetter = newProperty.getSetter(type, newMap);
-            final Class<?>     ct = getCurrentType();
+            final Class<?>     ct = getLocalType();
             mh = MH.filterArguments(widerSetter, 0, MH.insertArguments(debugReplace(ct, type, currentMap, newMap) , 1, newMap));
             if (ct != null && ct.isPrimitive() && !type.isPrimitive()) {
                  mh = ObjectClassGenerator.createGuardBoxedPrimitiveSetter(ct, generateSetter(ct, ct), mh);
             }
         } else {
-            final Class<?> forType = isUndefined() ? type : getCurrentType();
+            final Class<?> forType = isUndefined() ? type : getLocalType();
             mh = generateSetter(!forType.isPrimitive() ? Object.class : forType, type);
         }
 
@@ -681,24 +674,13 @@
             return false;
         }
         // Return true for currently undefined even if non-writable/configurable to allow initialization of ES6 CONST.
-        return getCurrentType() == null || (getCurrentType() != Object.class && (isConfigurable() || isWritable()));
+        return getLocalType() == null || (getLocalType() != Object.class && (isConfigurable() || isWritable()));
     }
 
     private boolean needsInvalidator(final int typeIndex, final int currentTypeIndex) {
         return canChangeType() && typeIndex > currentTypeIndex;
     }
 
-    @Override
-    public final void setCurrentType(final Class<?> currentType) {
-        assert currentType != boolean.class : "no boolean storage support yet - fix this";
-        this.currentType = currentType == null ? null : currentType.isPrimitive() ? currentType : Object.class;
-    }
-
-    @Override
-    public Class<?> getCurrentType() {
-        return currentType;
-    }
-
     private MethodHandle debug(final MethodHandle mh, final Class<?> forType, final Class<?> type, final String tag) {
         if (!Context.DEBUG || !Global.hasInstance()) {
             return mh;

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/FindProperty.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/FindProperty.java	Thu Oct 30 19:55:56 2014 +0100
@@ -84,13 +84,18 @@
      * @return method handle for the getter
      */
     public MethodHandle getGetter(final Class<?> type, final int programPoint, final LinkRequest request) {
-        final MethodHandle getter;
+        MethodHandle getter;
         if (isValid(programPoint)) {
             getter = property.getOptimisticGetter(type, programPoint);
         } else {
             getter = property.getGetter(type);
         }
         if (property instanceof UserAccessorProperty) {
+            getter = MH.insertArguments(getter, 1, UserAccessorProperty.getINVOKE_UA_GETTER(type, programPoint));
+            if (isValid(programPoint) && type.isPrimitive()) {
+                getter = MH.insertArguments(getter, 1, programPoint);
+            }
+            property.setType(type);
             return insertAccessorsGetter((UserAccessorProperty) property, request, getter);
         }
         return getter;
@@ -111,7 +116,8 @@
     public MethodHandle getSetter(final Class<?> type, final boolean strict, final LinkRequest request) {
         MethodHandle setter = property.getSetter(type, getOwner().getMap());
         if (property instanceof UserAccessorProperty) {
-            setter =  MH.insertArguments(setter, 1, strict ? property.getKey() : null);
+            setter =  MH.insertArguments(setter, 1, UserAccessorProperty.getINVOKE_UA_SETTER(type), strict ? property.getKey() : null);
+            property.setType(type);
             return insertAccessorsGetter((UserAccessorProperty) property, request, setter);
         }
 

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/Property.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/Property.java	Thu Oct 30 19:55:56 2014 +0100
@@ -102,6 +102,13 @@
     /** Property field number or spill slot. */
     private final int slot;
 
+    /**
+     * Current type of this object, in object only mode, this is an Object.class. In dual-fields mode
+     * null means undefined, and primitive types are allowed. The reason a special type is used for
+     * undefined, is that are no bits left to represent it in primitive types
+     */
+    private Class<?> type;
+
     /** SwitchPoint that is invalidated when property is changed, optional */
     protected transient SwitchPoint builtinSwitchPoint;
 
@@ -536,7 +543,7 @@
      * <p>
      * see {@link ObjectClassGenerator#createSetter(Class, Class, MethodHandle, MethodHandle)}
      * if you are interested in the internal details of this. Note that if you
-     * are running in default mode, with {@code -Dnashorn.fields.dual=true}, disabled, the setters
+     * are running with {@code -Dnashorn.fields.objects=true}, the setters
      * will currently never change, as all properties are represented as Object field,
      * the Object fields are Initialized to {@code ScriptRuntime.UNDEFINED} and primitives are
      * boxed/unboxed upon every access, which is not necessarily optimal
@@ -569,7 +576,7 @@
 
     @Override
     public int hashCode() {
-        final Class<?> type = getCurrentType();
+        final Class<?> type = getLocalType();
         return Objects.hashCode(this.key) ^ flags ^ getSlot() ^ (type == null ? 0 : type.hashCode());
     }
 
@@ -586,7 +593,7 @@
         final Property otherProperty = (Property)other;
 
         return equalsWithoutType(otherProperty) &&
-               getCurrentType() == otherProperty.getCurrentType();
+                getLocalType() == otherProperty.getLocalType();
     }
 
     boolean equalsWithoutType(final Property otherProperty) {
@@ -615,7 +622,7 @@
      */
     public final String toStringShort() {
         final StringBuilder sb   = new StringBuilder();
-        final Class<?>      type = getCurrentType();
+        final Class<?>      type = getLocalType();
         sb.append(getKey()).append(" (").append(type(type)).append(')');
         return sb.toString();
     }
@@ -632,7 +639,7 @@
     @Override
     public String toString() {
         final StringBuilder sb   = new StringBuilder();
-        final Class<?>      type = getCurrentType();
+        final Class<?>      type = getLocalType();
 
         sb.append(indent(getKey(), 20)).
             append(" id=").
@@ -656,20 +663,40 @@
     }
 
     /**
-     * Get the current type of this field. If you are not running with dual fields enabled,
+     * Get the current type of this property. If you are running with object fields enabled,
      * this will always be Object.class. See the value representation explanation in
      * {@link Property#getSetter(Class, PropertyMap)} and {@link ObjectClassGenerator}
      * for more information.
      *
+     * <p>Note that for user accessor properties, this returns the type of the last observed
+     * value passed to or returned by a user accessor. Use {@link #getLocalType()} to always get
+     * the type of the actual value stored in the property slot.</p>
+     *
      * @return current type of property, null means undefined
      */
-    public abstract Class<?> getCurrentType();
+    public final Class<?> getType() {
+        return type;
+    }
 
     /**
-     * Reset the current type of this property
-     * @param currentType new current type
+     * Set the type of this property.
+     * @param type new type
      */
-    public abstract void setCurrentType(final Class<?> currentType);
+    public final void setType(final Class<?> type) {
+        assert type != boolean.class : "no boolean storage support yet - fix this";
+        this.type = type == null ? null : type.isPrimitive() ? type : Object.class;
+    }
+
+    /**
+     * Get the type of the value in the local property slot. This returns the same as
+     * {@link #getType()} for normal properties, but always returns {@code Object.class}
+     * for {@link UserAccessorProperty}s as their local type is a pair of accessor references.
+     *
+     * @return the local property type
+     */
+    protected Class<?> getLocalType() {
+        return getType();
+    }
 
     /**
      * Check whether this Property can ever change its type. The default is false, and if

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/PropertyMap.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/PropertyMap.java	Thu Oct 30 19:55:56 2014 +0100
@@ -512,7 +512,7 @@
         assert sameType ||
                 oldProperty instanceof AccessorProperty &&
                 newProperty instanceof UserAccessorProperty :
-            "arbitrary replaceProperty attempted " + sameType + " oldProperty=" + oldProperty.getClass() + " newProperty=" + newProperty.getClass() + " [" + oldProperty.getCurrentType() + " => " + newProperty.getCurrentType() + "]";
+            "arbitrary replaceProperty attempted " + sameType + " oldProperty=" + oldProperty.getClass() + " newProperty=" + newProperty.getClass() + " [" + oldProperty.getLocalType() + " => " + newProperty.getLocalType() + "]";
 
         newMap.flags = flags;
 

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/ScriptObject.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/ScriptObject.java	Thu Oct 30 19:55:56 2014 +0100
@@ -969,7 +969,7 @@
             final UserAccessorProperty uc = (UserAccessorProperty)oldProperty;
             final int slot = uc.getSlot();
 
-            assert uc.getCurrentType() == Object.class;
+            assert uc.getLocalType() == Object.class;
             if (slot >= spillLength) {
                 uc.setAccessors(this, getMap(), new UserAccessorProperty.Accessors(getter, setter));
             } else {

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/SpillProperty.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/SpillProperty.java	Thu Oct 30 19:55:56 2014 +0100
@@ -161,12 +161,12 @@
      */
     public SpillProperty(final String key, final int flags, final int slot) {
         super(key, flags, slot, primitiveGetter(slot), primitiveSetter(slot), objectGetter(slot), objectSetter(slot));
-        assert !OBJECT_FIELDS_ONLY || getCurrentType() == Object.class;
+        assert !OBJECT_FIELDS_ONLY || getLocalType() == Object.class;
     }
 
     SpillProperty(final String key, final int flags, final int slot, final Class<?> initialType) {
         this(key, flags, slot);
-        setCurrentType(OBJECT_FIELDS_ONLY ? Object.class : initialType);
+        setType(OBJECT_FIELDS_ONLY ? Object.class : initialType);
     }
 
     SpillProperty(final String key, final int flags, final int slot, final ScriptObject owner, final Object initialValue) {

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/UserAccessorProperty.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/UserAccessorProperty.java	Thu Oct 30 19:55:56 2014 +0100
@@ -27,16 +27,16 @@
 
 import static jdk.nashorn.internal.lookup.Lookup.MH;
 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
-import static jdk.nashorn.internal.runtime.JSType.CONVERT_OBJECT_OPTIMISTIC;
-import static jdk.nashorn.internal.runtime.JSType.getAccessorTypeIndex;
 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
+import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT;
+import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_PROGRAM_POINT_SHIFT;
 
 import java.lang.invoke.MethodHandle;
 import java.lang.invoke.MethodHandles;
 import java.lang.invoke.MethodType;
-import java.util.concurrent.Callable;
 import jdk.nashorn.internal.lookup.Lookup;
 import jdk.nashorn.internal.runtime.linker.Bootstrap;
+import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;
 
 /**
  * Property with user defined getters/setters. Actual getter and setter
@@ -69,38 +69,29 @@
     private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
 
     /** Getter method handle */
-    private final static MethodHandle INVOKE_GETTER_ACCESSOR = findOwnMH_S("invokeGetterAccessor", Object.class, Accessors.class, Object.class);
+    private final static MethodHandle INVOKE_OBJECT_GETTER = findOwnMH_S("invokeObjectGetter", Object.class, Accessors.class, MethodHandle.class, Object.class);
+    private final static MethodHandle INVOKE_INT_GETTER  = findOwnMH_S("invokeIntGetter", int.class, Accessors.class, MethodHandle.class, int.class, Object.class);
+    private final static MethodHandle INVOKE_LONG_GETTER  = findOwnMH_S("invokeLongGetter", long.class, Accessors.class, MethodHandle.class, int.class, Object.class);
+    private final static MethodHandle INVOKE_NUMBER_GETTER  = findOwnMH_S("invokeNumberGetter", double.class, Accessors.class, MethodHandle.class, int.class, Object.class);
 
     /** Setter method handle */
-    private final static MethodHandle INVOKE_SETTER_ACCESSOR = findOwnMH_S("invokeSetterAccessor", void.class, Accessors.class, String.class, Object.class, Object.class);
+    private final static MethodHandle INVOKE_OBJECT_SETTER = findOwnMH_S("invokeObjectSetter", void.class, Accessors.class, MethodHandle.class, String.class, Object.class, Object.class);
+    private final static MethodHandle INVOKE_INT_SETTER = findOwnMH_S("invokeIntSetter", void.class, Accessors.class, MethodHandle.class, String.class, Object.class, int.class);
+    private final static MethodHandle INVOKE_LONG_SETTER = findOwnMH_S("invokeLongSetter", void.class, Accessors.class, MethodHandle.class, String.class, Object.class, long.class);
+    private final static MethodHandle INVOKE_NUMBER_SETTER = findOwnMH_S("invokeNumberSetter", void.class, Accessors.class, MethodHandle.class, String.class, Object.class, double.class);
 
-    /** Dynamic invoker for getter */
-    private static final Object GETTER_INVOKER_KEY = new Object();
-
-    private static MethodHandle getINVOKE_UA_GETTER() {
 
-        return Context.getGlobal().getDynamicInvoker(GETTER_INVOKER_KEY,
-                new Callable<MethodHandle>() {
-                    @Override
-                    public MethodHandle call() {
-                        return Bootstrap.createDynamicInvoker("dyn:call", Object.class,
-                            Object.class, Object.class);
-                    }
-                });
+    static MethodHandle getINVOKE_UA_GETTER(final Class<?> returnType, final int programPoint) {
+        if (UnwarrantedOptimismException.isValid(programPoint)) {
+            final int flags = NashornCallSiteDescriptor.CALLSITE_OPTIMISTIC | programPoint << CALLSITE_PROGRAM_POINT_SHIFT;
+            return Bootstrap.createDynamicInvoker("dyn:call", flags, returnType, Object.class, Object.class);
+        } else {
+            return Bootstrap.createDynamicInvoker("dyn:call", Object.class, Object.class, Object.class);
+        }
     }
 
-    /** Dynamic invoker for setter */
-    private static Object SETTER_INVOKER_KEY = new Object();
-
-    private static MethodHandle getINVOKE_UA_SETTER() {
-        return Context.getGlobal().getDynamicInvoker(SETTER_INVOKER_KEY,
-                new Callable<MethodHandle>() {
-                    @Override
-                    public MethodHandle call() {
-                        return Bootstrap.createDynamicInvoker("dyn:call", void.class,
-                            Object.class, Object.class, Object.class);
-                    }
-                });
+    static MethodHandle getINVOKE_UA_SETTER(final Class<?> valueType) {
+        return Bootstrap.createDynamicInvoker("dyn:call", void.class, Object.class, Object.class, valueType);
     }
 
     /**
@@ -158,7 +149,7 @@
     }
 
     @Override
-    public Class<?> getCurrentType() {
+    protected Class<?> getLocalType() {
         return Object.class;
     }
 
@@ -189,7 +180,13 @@
 
     @Override
     public Object getObjectValue(final ScriptObject self, final ScriptObject owner) {
-        return invokeGetterAccessor(getAccessors((owner != null) ? owner : self), self);
+        try {
+            return invokeObjectGetter(getAccessors((owner != null) ? owner : self), getINVOKE_UA_GETTER(Object.class, INVALID_PROGRAM_POINT), self);
+        } catch (final Error | RuntimeException t) {
+            throw t;
+        } catch (final Throwable t) {
+            throw new RuntimeException(t);
+        }
     }
 
     @Override
@@ -209,41 +206,33 @@
 
     @Override
     public void setValue(final ScriptObject self, final ScriptObject owner, final Object value, final boolean strict) {
-        invokeSetterAccessor(getAccessors((owner != null) ? owner : self), strict ? getKey() : null, self, value);
+        try {
+            invokeObjectSetter(getAccessors((owner != null) ? owner : self), getINVOKE_UA_SETTER(Object.class), strict ? getKey() : null, self, value);
+        } catch (final Error | RuntimeException t) {
+            throw t;
+        } catch (final Throwable t) {
+            throw new RuntimeException(t);
+        }
     }
 
     @Override
     public MethodHandle getGetter(final Class<?> type) {
         //this returns a getter on the format (Accessors, Object receiver)
-        return Lookup.filterReturnType(INVOKE_GETTER_ACCESSOR, type);
+        return Lookup.filterReturnType(INVOKE_OBJECT_GETTER, type);
     }
 
     @Override
     public MethodHandle getOptimisticGetter(final Class<?> type, final int programPoint) {
-        //fortype is always object, but in the optimistic world we have to throw
-        //unwarranted optimism exception for narrower types. We can improve this
-        //by checking for boxed types and unboxing them, but it is doubtful that
-        //this gives us any performance, as UserAccessorProperties are typically not
-        //primitives. Are there? TODO: investigate later. For now we just throw an
-        //exception for narrower types than object
-
-        if (type.isPrimitive()) {
-            final MethodHandle getter = getGetter(Object.class);
-            final MethodHandle mh =
-                    MH.asType(
-                            MH.filterReturnValue(
-                                    getter,
-                                    MH.insertArguments(
-                                            CONVERT_OBJECT_OPTIMISTIC.get(getAccessorTypeIndex(type)),
-                                            1,
-                                            programPoint)),
-                                    getter.type().changeReturnType(type));
-
-            return mh;
+        if (type == int.class) {
+            return INVOKE_INT_GETTER;
+        } else if (type == long.class) {
+            return INVOKE_LONG_GETTER;
+        } else if (type == double.class) {
+            return INVOKE_NUMBER_GETTER;
+        } else {
+            assert type == Object.class;
+            return INVOKE_OBJECT_GETTER;
         }
-
-        assert type == Object.class;
-        return getGetter(type);
     }
 
     @Override
@@ -259,7 +248,16 @@
 
     @Override
     public MethodHandle getSetter(final Class<?> type, final PropertyMap currentMap) {
-        return INVOKE_SETTER_ACCESSOR;
+        if (type == int.class) {
+            return INVOKE_INT_SETTER;
+        } else if (type == long.class) {
+            return INVOKE_LONG_SETTER;
+        } else if (type == double.class) {
+            return INVOKE_NUMBER_SETTER;
+        } else {
+            assert type == Object.class;
+            return INVOKE_OBJECT_SETTER;
+        }
     }
 
     @Override
@@ -282,31 +280,81 @@
     // getter/setter may be inherited. If so, proto is bound during lookup. In either
     // inherited or self case, slot is also bound during lookup. Actual ScriptFunction
     // to be called is retrieved everytime and applied.
-    private static Object invokeGetterAccessor(final Accessors gs, final Object self) {
+    @SuppressWarnings("unused")
+    private static Object invokeObjectGetter(final Accessors gs, final MethodHandle invoker, final Object self) throws Throwable {
         final Object func = gs.getter;
         if (func instanceof ScriptFunction) {
-            try {
-                return getINVOKE_UA_GETTER().invokeExact(func, self);
-            } catch (final Error | RuntimeException t) {
-                throw t;
-            } catch (final Throwable t) {
-                throw new RuntimeException(t);
-            }
+            return invoker.invokeExact(func, self);
         }
 
         return UNDEFINED;
     }
 
-    private static void invokeSetterAccessor(final Accessors gs, final String name, final Object self, final Object value) {
+    @SuppressWarnings("unused")
+    private static int invokeIntGetter(final Accessors gs, final MethodHandle invoker, final int programPoint, final Object self) throws Throwable {
+        final Object func = gs.getter;
+        if (func instanceof ScriptFunction) {
+            return (int) invoker.invokeExact(func, self);
+        }
+
+        throw new UnwarrantedOptimismException(UNDEFINED, programPoint);
+    }
+
+    @SuppressWarnings("unused")
+    private static long invokeLongGetter(final Accessors gs, final MethodHandle invoker, final int programPoint, final Object self) throws Throwable {
+        final Object func = gs.getter;
+        if (func instanceof ScriptFunction) {
+            return (long) invoker.invokeExact(func, self);
+        }
+
+        throw new UnwarrantedOptimismException(UNDEFINED, programPoint);
+    }
+
+    @SuppressWarnings("unused")
+    private static double invokeNumberGetter(final Accessors gs, final MethodHandle invoker, final int programPoint, final Object self) throws Throwable {
+        final Object func = gs.getter;
+        if (func instanceof ScriptFunction) {
+            return (double) invoker.invokeExact(func, self);
+        }
+
+        throw new UnwarrantedOptimismException(UNDEFINED, programPoint);
+    }
+
+    @SuppressWarnings("unused")
+    private static void invokeObjectSetter(final Accessors gs, final MethodHandle invoker, final String name, final Object self, final Object value) throws Throwable {
         final Object func = gs.setter;
         if (func instanceof ScriptFunction) {
-            try {
-                getINVOKE_UA_SETTER().invokeExact(func, self, value);
-            } catch (final Error | RuntimeException t) {
-                throw t;
-            } catch (final Throwable t) {
-                throw new RuntimeException(t);
-            }
+            invoker.invokeExact(func, self, value);
+        } else if (name != null) {
+            throw typeError("property.has.no.setter", name, ScriptRuntime.safeToString(self));
+        }
+    }
+
+    @SuppressWarnings("unused")
+    private static void invokeIntSetter(final Accessors gs, final MethodHandle invoker, final String name, final Object self, final int value) throws Throwable {
+        final Object func = gs.setter;
+        if (func instanceof ScriptFunction) {
+            invoker.invokeExact(func, self, value);
+        } else if (name != null) {
+            throw typeError("property.has.no.setter", name, ScriptRuntime.safeToString(self));
+        }
+    }
+
+    @SuppressWarnings("unused")
+    private static void invokeLongSetter(final Accessors gs, final MethodHandle invoker, final String name, final Object self, final long value) throws Throwable {
+        final Object func = gs.setter;
+        if (func instanceof ScriptFunction) {
+            invoker.invokeExact(func, self, value);
+        } else if (name != null) {
+            throw typeError("property.has.no.setter", name, ScriptRuntime.safeToString(self));
+        }
+    }
+
+    @SuppressWarnings("unused")
+    private static void invokeNumberSetter(final Accessors gs, final MethodHandle invoker, final String name, final Object self, final double value) throws Throwable {
+        final Object func = gs.setter;
+        if (func instanceof ScriptFunction) {
+            invoker.invokeExact(func, self, value);
         } else if (name != null) {
             throw typeError("property.has.no.setter", name, ScriptRuntime.safeToString(self));
         }

--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/linker/Bootstrap.java	Tue Oct 28 17:22:17 2014 +0530
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/linker/Bootstrap.java	Thu Oct 30 19:55:56 2014 +0100
@@ -337,6 +337,20 @@
 
     /**
      * Returns a dynamic invoker for a specified dynamic operation using the public lookup. Similar to
+     * {@link #createDynamicInvoker(String, Class, Class...)} but with an additional parameter to
+     * set the call site flags of the dynamic invoker.
+     * @param opDesc Dynalink dynamic operation descriptor.
+     * @param flags the call site flags for the operation
+     * @param rtype the return type for the operation
+     * @param ptypes the parameter types for the operation
+     * @return MethodHandle for invoking the operation.
+     */
+    public static MethodHandle createDynamicInvoker(final String opDesc, final int flags, final Class<?> rtype, final Class<?>... ptypes) {
+        return bootstrap(MethodHandles.publicLookup(), opDesc, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker();
+    }
+
+    /**
+     * Returns a dynamic invoker for a specified dynamic operation using the public lookup. Similar to
      * {@link #createDynamicInvoker(String, Class, Class...)} but with return and parameter types composed into a
      * method type in the signature. See the discussion of that method for details.
      * @param opDesc Dynalink dynamic operation descriptor.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/examples/getter-setter-micro.js	Thu Oct 30 19:55:56 2014 +0100
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Oracle nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * A micro-benchmark for getters and setters with primitive values,
+ * alternating between ints and doubles. Introduction of primitive
+ * and optimistic user accessors in JDK-8062401 make this faster by
+ * 10x or more by allowing inlining and other optimizations to take place.
+ */
+
+var x = {
+    get m() {
+        return this._m;
+    },
+    set m(v) {
+        this._m = v;
+    },
+    get n() {
+        return this._n;
+    },
+    set n(v) {
+        this._n = v;
+    }
+};
+
+
+function bench(v1, v2, result) {
+    var start = Date.now();
+    x.n = v1;
+    for (var i = 0; i < 1e8; i++) {
+        x.m = v2;
+        if (x.m + x.n !== result) {
+            throw "wrong result";
+        }
+    }
+    print("done in", Date.now() - start, "millis");
+}
+
+for (var i = 0; i < 10; i++) {
+    bench(i, 4, 4 + i);
+}
+
+for (var i = 0; i < 10; i++) {
+    bench(i, 4.5, 4.5 + i);
+}
+
+for (var i = 0; i < 10; i++) {
+    bench(i, 5, 5 + i);
+}
+
+for (var i = 0; i < 10; i++) {
+    bench(i, 5.5, 5.5 + i);
+}