Implement date library functions in C++.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index f3709efe3fa5c4f35233249aafba05d766513b4c..7906d14fa31dbb928a9242861aa17a1f2ff4f113 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6028,32 +6028,42 @@ class JSValue: public JSObject {
 };
 
 
+class DateCache;
+
 // Representation for JS date objects.
 class JSDate: public JSObject {
  public:
   // If one component is NaN, all of them are, indicating a NaN time value.
   // [value]: the time value.
   DECL_ACCESSORS(value, Object)
-  // [local]: the offset for the local time value.
-  DECL_ACCESSORS(local, Object)
   // [year]: caches year. Either undefined, smi, or NaN.
   DECL_ACCESSORS(year, Object)
   // [month]: caches month. Either undefined, smi, or NaN.
   DECL_ACCESSORS(month, Object)
   // [day]: caches day. Either undefined, smi, or NaN.
   DECL_ACCESSORS(day, Object)
+  // [weekday]: caches day of week. Either undefined, smi, or NaN.
+  DECL_ACCESSORS(weekday, Object)
   // [hour]: caches hours. Either undefined, smi, or NaN.
   DECL_ACCESSORS(hour, Object)
   // [min]: caches minutes. Either undefined, smi, or NaN.
   DECL_ACCESSORS(min, Object)
   // [sec]: caches seconds. Either undefined, smi, or NaN.
   DECL_ACCESSORS(sec, Object)
-  // [weekday]: caches day of week. Either undefined, smi, or NaN.
-  DECL_ACCESSORS(weekday, Object)
+  // [cache stamp]: sample of the date cache stamp at the
+  // moment when local fields were cached.
+  DECL_ACCESSORS(cache_stamp, Object)
 
   // Casting.
   static inline JSDate* cast(Object* obj);
 
+  // Returns the date field with the specified index.
+  // See FieldIndex for the list of date fields.
+  static MaybeObject* GetField(Object* date, Smi* index);
+
+  void SetValue(Object* value, bool is_value_nan);
+
+
   // Dispatched behavior.
 #ifdef OBJECT_PRINT
   inline void JSDatePrint() {
@@ -6064,23 +6074,56 @@ class JSDate: public JSObject {
 #ifdef DEBUG
   void JSDateVerify();
 #endif
+  // The order is important. It must be kept in sync with date macros
+  // in macros.py.
+  enum FieldIndex {
+    kDateValue,
+    kYear,
+    kMonth,
+    kDay,
+    kWeekday,
+    kHour,
+    kMinute,
+    kSecond,
+    kFirstUncachedField,
+    kMillisecond = kFirstUncachedField,
+    kDays,
+    kTimeInDay,
+    kFirstUTCField,
+    kYearUTC = kFirstUTCField,
+    kMonthUTC,
+    kDayUTC,
+    kWeekdayUTC,
+    kHourUTC,
+    kMinuteUTC,
+    kSecondUTC,
+    kMillisecondUTC,
+    kDaysUTC,
+    kTimeInDayUTC,
+    kTimezoneOffset
+  };
 
   // Layout description.
   static const int kValueOffset = JSObject::kHeaderSize;
-  static const int kLocalOffset = kValueOffset + kPointerSize;
-  static const int kYearOffset = kLocalOffset + kPointerSize;
+  static const int kYearOffset = kValueOffset + kPointerSize;
   static const int kMonthOffset = kYearOffset + kPointerSize;
   static const int kDayOffset = kMonthOffset + kPointerSize;
-  static const int kHourOffset = kDayOffset + kPointerSize;
+  static const int kWeekdayOffset = kDayOffset + kPointerSize;
+  static const int kHourOffset = kWeekdayOffset  + kPointerSize;
   static const int kMinOffset = kHourOffset + kPointerSize;
   static const int kSecOffset = kMinOffset + kPointerSize;
-  static const int kWeekdayOffset = kSecOffset + kPointerSize;
-  static const int kSize = kWeekdayOffset + kPointerSize;
-
-  // Index of first field not requiring a write barrier.
-  static const int kFirstBarrierFree = 2;  // year
+  static const int kCacheStampOffset = kSecOffset + kPointerSize;
+  static const int kSize = kCacheStampOffset + kPointerSize;
 
  private:
+  inline Object* DoGetField(FieldIndex index);
+
+  Object* GetUTCField(FieldIndex index, double value, DateCache* date_cache);
+
+  // Computes and caches the cacheable fields of the date.
+  inline void SetLocalFields(int64_t local_time_ms, DateCache* date_cache);
+
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSDate);
 };