[es6] Introduce a dedicated JSIteratorResult type.

src/hydrogen.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.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast-numbering.h"
@@ skipping 1798 matching lines @@
   Push(count);
 
   probe_loop.EndBody();
 
   return_or_loop.End();
 
   return Pop();
 }
 
 
+HValue* HGraphBuilder::BuildCreateIterResultObject(HValue* value,
+                                                   HValue* done) {
+  NoObservableSideEffectsScope scope(this);
+
+  // Allocate the JSIteratorResult object.
+  HValue* result =
+      Add<HAllocate>(Add<HConstant>(JSIteratorResult::kSize), HType::JSObject(),
+                     NOT_TENURED, JS_ITERATOR_RESULT_TYPE);
+
+  // Initialize the JSIteratorResult object.
+  HValue* native_context = BuildGetNativeContext();
+  HValue* map = Add<HLoadNamedField>(
+      native_context, nullptr,
+      HObjectAccess::ForContextSlot(Context::ITERATOR_RESULT_MAP_INDEX));
+  Add<HStoreNamedField>(result, HObjectAccess::ForMap(), map);
+  HValue* empty_fixed_array = Add<HLoadRoot>(Heap::kEmptyFixedArrayRootIndex);
+  Add<HStoreNamedField>(result, HObjectAccess::ForPropertiesPointer(),
+                        empty_fixed_array);
+  Add<HStoreNamedField>(result, HObjectAccess::ForElementsPointer(),
+                        empty_fixed_array);
+  Add<HStoreNamedField>(result, HObjectAccess::ForObservableJSObjectOffset(
+                                    JSIteratorResult::kValueOffset),
+                        value);
+  Add<HStoreNamedField>(result, HObjectAccess::ForObservableJSObjectOffset(
+                                    JSIteratorResult::kDoneOffset),
+                        done);
+  STATIC_ASSERT(JSIteratorResult::kSize == 5 * kPointerSize);
+  return result;
+}
+
+
 HValue* HGraphBuilder::BuildRegExpConstructResult(HValue* length,
                                                   HValue* index,
                                                   HValue* input) {
   NoObservableSideEffectsScope scope(this);
   HConstant* max_length = Add<HConstant>(JSObject::kInitialMaxFastElementArray);
   Add<HBoundsCheck>(length, max_length);
 
   // Generate size calculation code here in order to make it dominate
   // the JSRegExpResult allocation.
   ElementsKind elements_kind = FAST_ELEMENTS;
@@ skipping 10761 matching lines @@
   return ast_context()->ReturnValue(graph()->GetConstantUndefined());
 }
 
 
 void HOptimizedGraphBuilder::GenerateTheHole(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 0);
   return ast_context()->ReturnValue(graph()->GetConstantHole());
 }
 
 
+void HOptimizedGraphBuilder::GenerateCreateIterResultObject(CallRuntime* call) {
+  DCHECK_EQ(2, call->arguments()->length());
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(1)));
+  HValue* done = Pop();
+  HValue* value = Pop();
+  HValue* result = BuildCreateIterResultObject(value, done);
+  return ast_context()->ReturnValue(result);
+}
+
+
 void HOptimizedGraphBuilder::GenerateJSCollectionGetTable(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* receiver = Pop();
   HInstruction* result = New<HLoadNamedField>(
       receiver, nullptr, HObjectAccess::ForJSCollectionTable());
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
@@ skipping 841 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8