New class for Date objects: caches individual date components.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 76c8443e7c30cc422154eab202c61dba16e5941e..4f44d069af98c5f8d7c0e86c207d6b31e80b4cad 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -1431,6 +1431,49 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
 }
 
 
+void LCodeGen::DoDateField(LDateField* instr) {
+  Register input = ToRegister(instr->InputAt(0));
+  Register result = ToRegister(instr->result());
+  Register map = ToRegister(instr->TempAt(0));
+
+#ifdef DEBUG
+  __ AbortIfSmi(input);
+  __ CompareObjectType(input, map, map, JS_DATE_TYPE);
+  __ Assert(eq, "Trying to get date field from non-date.");
+#endif
+
+  __ ldr(result, FieldMemOperand(input,
+                     JSDate::kValueOffset + kPointerSize * instr->index()));
+}
+
+
+void LCodeGen::DoSetDateField(LSetDateField* instr) {
+  Register date = ToRegister(instr->InputAt(0));
+  Register value = ToRegister(instr->InputAt(1));
+  Register result = ToRegister(instr->result());
+  Register temp = ToRegister(instr->TempAt(0));
+  int index = instr->index();
+
+#ifdef DEBUG
+  __ AbortIfSmi(date);
+  __ CompareObjectType(date, temp, temp, JS_DATE_TYPE);
+  __ Assert(eq, "Trying to get date field from non-date.");
+#endif
+
+  __ str(value,
+         FieldMemOperand(date, JSDate::kValueOffset + kPointerSize * index));
+  // Caches can only be smi or NaN, so we can skip the write barrier for them.
+  if (index < JSDate::kFirstBarrierFree) {
+    // Update the write barrier.  Save the value as it will be
+    // overwritten by the write barrier code and is needed afterward.
+    __ mov(result, value);
+    __ RecordWriteField(
+        date, JSDate::kValueOffset + kPointerSize * index,
+        value, temp, kLRHasBeenSaved, kDontSaveFPRegs);
+  }
+}
+
+
 void LCodeGen::DoBitNotI(LBitNotI* instr) {
   Register input = ToRegister(instr->InputAt(0));
   Register result = ToRegister(instr->result());