[es6] Introduce a dedicated JSIteratorResult type.

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index 1e01b0d77e12c9b5fc72fdce614246cca3cc3ef5..d72dd71bd673b2a0bcb9af51cf379af7ef3f3a04 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -4172,6 +4172,49 @@ void FullCodeGenerator::EmitDebugIsActive(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitCreateIterResultObject(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  DCHECK_EQ(2, args->length());
+  VisitForStackValue(args->at(0));
+  VisitForStackValue(args->at(1));
+
+  Label runtime, done;
+
+  Register result = x0;
+  __ Allocate(JSIteratorResult::kSize, result, x10, x11, &runtime, TAG_OBJECT);
+  Register map_reg = x1;
+  Register result_value = x2;
+  Register boolean_done = x3;
+  Register empty_fixed_array = x4;
+  Register untagged_result = x5;
+  __ Ldr(map_reg, GlobalObjectMemOperand());
+  __ Ldr(map_reg, FieldMemOperand(map_reg, GlobalObject::kNativeContextOffset));
+  __ Ldr(map_reg,
+         ContextMemOperand(map_reg, Context::ITERATOR_RESULT_MAP_INDEX));
+  __ Pop(boolean_done);
+  __ Pop(result_value);
+  __ LoadRoot(empty_fixed_array, Heap::kEmptyFixedArrayRootIndex);
+  STATIC_ASSERT(JSObject::kPropertiesOffset + kPointerSize ==
+                JSObject::kElementsOffset);
+  STATIC_ASSERT(JSIteratorResult::kValueOffset + kPointerSize ==
+                JSIteratorResult::kDoneOffset);
+  __ ObjectUntag(untagged_result, result);
+  __ Str(map_reg, MemOperand(untagged_result, HeapObject::kMapOffset));
+  __ Stp(empty_fixed_array, empty_fixed_array,
+         MemOperand(untagged_result, JSObject::kPropertiesOffset));
+  __ Stp(result_value, boolean_done,
+         MemOperand(untagged_result, JSIteratorResult::kValueOffset));
+  STATIC_ASSERT(JSIteratorResult::kSize == 5 * kPointerSize);
+  __ B(&done);
+
+  __ Bind(&runtime);
+  __ CallRuntime(Runtime::kCreateIterResultObject, 2);
+
+  __ Bind(&done);
+  context()->Plug(x0);
+}
+
+
 void FullCodeGenerator::EmitLoadJSRuntimeFunction(CallRuntime* expr) {
   // Push undefined as the receiver.
   __ LoadRoot(x0, Heap::kUndefinedValueRootIndex);
@@ -5085,26 +5128,19 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
 
 
 void FullCodeGenerator::EmitCreateIteratorResult(bool done) {
-  Label gc_required;
-  Label allocated;
-
-  const int instance_size = 5 * kPointerSize;
-  DCHECK_EQ(isolate()->native_context()->iterator_result_map()->instance_size(),
-            instance_size);
+  Label allocate, done_allocate;
 
   // Allocate and populate an object with this form: { value: VAL, done: DONE }
 
   Register result = x0;
-  __ Allocate(instance_size, result, x10, x11, &gc_required, TAG_OBJECT);
-  __ B(&allocated);
+  __ Allocate(JSIteratorResult::kSize, result, x10, x11, &allocate, TAG_OBJECT);
+  __ B(&done_allocate);
 
-  __ Bind(&gc_required);
-  __ Push(Smi::FromInt(instance_size));
+  __ Bind(&allocate);
+  __ Push(Smi::FromInt(JSIteratorResult::kSize));
   __ CallRuntime(Runtime::kAllocateInNewSpace, 1);
-  __ Ldr(context_register(),
-         MemOperand(fp, StandardFrameConstants::kContextOffset));
 
-  __ Bind(&allocated);
+  __ Bind(&done_allocate);
   Register map_reg = x1;
   Register result_value = x2;
   Register boolean_done = x3;
@@ -5115,24 +5151,20 @@ void FullCodeGenerator::EmitCreateIteratorResult(bool done) {
   __ Ldr(map_reg,
          ContextMemOperand(map_reg, Context::ITERATOR_RESULT_MAP_INDEX));
   __ Pop(result_value);
-  __ Mov(boolean_done, Operand(isolate()->factory()->ToBoolean(done)));
-  __ Mov(empty_fixed_array, Operand(isolate()->factory()->empty_fixed_array()));
+  __ LoadRoot(boolean_done,
+              done ? Heap::kTrueValueRootIndex : Heap::kFalseValueRootIndex);
+  __ LoadRoot(empty_fixed_array, Heap::kEmptyFixedArrayRootIndex);
   STATIC_ASSERT(JSObject::kPropertiesOffset + kPointerSize ==
                 JSObject::kElementsOffset);
-  STATIC_ASSERT(JSGeneratorObject::kResultValuePropertyOffset + kPointerSize ==
-                JSGeneratorObject::kResultDonePropertyOffset);
+  STATIC_ASSERT(JSIteratorResult::kValueOffset + kPointerSize ==
+                JSIteratorResult::kDoneOffset);
   __ ObjectUntag(untagged_result, result);
   __ Str(map_reg, MemOperand(untagged_result, HeapObject::kMapOffset));
   __ Stp(empty_fixed_array, empty_fixed_array,
          MemOperand(untagged_result, JSObject::kPropertiesOffset));
   __ Stp(result_value, boolean_done,
-         MemOperand(untagged_result,
-                    JSGeneratorObject::kResultValuePropertyOffset));
-
-  // Only the value field needs a write barrier, as the other values are in the
-  // root set.
-  __ RecordWriteField(result, JSGeneratorObject::kResultValuePropertyOffset,
-                      x10, x11, kLRHasBeenSaved, kDontSaveFPRegs);
+         MemOperand(untagged_result, JSIteratorResult::kValueOffset));
+  STATIC_ASSERT(JSIteratorResult::kSize == 5 * kPointerSize);
 }