[es6] Introduce a dedicated JSIteratorResult type.

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

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/compiler.h"
@@ skipping 4154 matching lines @@
   DCHECK(expr->arguments()->length() == 0);
   ExternalReference debug_is_active =
       ExternalReference::debug_is_active_address(isolate());
   __ Mov(x10, debug_is_active);
   __ Ldrb(x0, MemOperand(x10));
   __ SmiTag(x0);
   context()->Plug(x0);
 }
 
 
+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);
   __ Push(x0);
 
   __ Ldr(x0, GlobalObjectMemOperand());
   __ Ldr(x0, FieldMemOperand(x0, GlobalObject::kNativeContextOffset));
   __ Ldr(x0, ContextMemOperand(x0, expr->context_index()));
 }
 
@@ skipping 893 matching lines @@
   __ CallRuntime(Runtime::kResumeJSGeneratorObject, 3);
   // Not reached: the runtime call returns elsewhere.
   __ Unreachable();
 
   __ Bind(&done);
   context()->Plug(result_register());
 }
 
 
 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;
   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(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);
 }
 
 
 // TODO(all): I don't like this method.
 // It seems to me that in too many places x0 is used in place of this.
 // Also, this function is not suitable for all places where x0 should be
 // abstracted (eg. when used as an argument). But some places assume that the
 // first argument register is x0, and use this function instead.
 // Considering that most of the register allocation is hard-coded in the
 // FullCodeGen, that it is unlikely we will need to change it extensively, and
@@ skipping 196 matching lines @@
   }
 
   return INTERRUPT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64