New class for Date objects: caches individual date components.

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 67bf9376c71b38e86e7d206e6d7a92c0d6b9fdd4..01f86b9f5bc3bff4eb9a5584e6ce353e55a294ac 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -166,7 +166,8 @@ class LCodeGen;
   V(TypeofIsAndBranch)                          \
   V(UnaryMathOperation)                         \
   V(UnknownOSRValue)                            \
-  V(ValueOf)
+  V(ValueOf)                                    \
+  V(DateField)
 
 
 #define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)              \
@@ -996,6 +997,23 @@ class LValueOf: public LTemplateInstruction<1, 1, 1> {
 };
 
 
+class LDateField: public LTemplateInstruction<1, 1, 1> {
+ public:
+  LDateField(LOperand* value, LOperand* temp, int index) : index_(index) {
+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(DateField, "date-field")
+  DECLARE_HYDROGEN_ACCESSOR(DateField)
+
+  int index() const { return index_; }
+
+ private:
+  int index_;
+};
+
+
 class LThrow: public LTemplateInstruction<0, 2, 0> {
  public:
   LThrow(LOperand* context, LOperand* value) {