[generators] Implement %GeneratorGetSourcePosition.

src/compiler/js-typed-lowering.cc

 // Copyright 2014 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/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/linkage.h"
@@ skipping 1709 matching lines @@
   DCHECK_EQ(IrOpcode::kJSForInStep, node->opcode());
   node->ReplaceInput(1, jsgraph()->Int32Constant(1));
   NodeProperties::ChangeOp(node, machine()->Int32Add());
   return Changed(node);
 }
 
 Reduction JSTypedLowering::ReduceJSGeneratorStore(Node* node) {
   DCHECK_EQ(IrOpcode::kJSGeneratorStore, node->opcode());
   Node* generator = NodeProperties::GetValueInput(node, 0);
   Node* continuation = NodeProperties::GetValueInput(node, 1);
+  Node* offset = NodeProperties::GetValueInput(node, 2);
   Node* context = NodeProperties::GetContextInput(node);
   Node* effect = NodeProperties::GetEffectInput(node);
   Node* control = NodeProperties::GetControlInput(node);
   int register_count = OpParameter<int>(node);
 
   FieldAccess array_field = AccessBuilder::ForJSGeneratorObjectOperandStack();
   FieldAccess context_field = AccessBuilder::ForJSGeneratorObjectContext();
   FieldAccess continuation_field =
       AccessBuilder::ForJSGeneratorObjectContinuation();
+  FieldAccess input_field = AccessBuilder::ForJSGeneratorObjectInput();

[Jarin, 2016/06/20 07:56:49]

Please, add some explanation why it is ok to hijack the input field for offset.
Maybe we should consider to rename the field to reflect the dual purpose of the
field.

[rmcilroy, 2016/06/20 11:11:26]

+1

 
   Node* array = effect = graph()->NewNode(simplified()->LoadField(array_field),
                                           generator, effect, control);
 
   for (int i = 0; i < register_count; ++i) {
-    Node* value = NodeProperties::GetValueInput(node, 2 + i);
+    Node* value = NodeProperties::GetValueInput(node, 3 + i);
     effect = graph()->NewNode(
         simplified()->StoreField(AccessBuilder::ForFixedArraySlot(i)), array,
         value, effect, control);
   }
 
   effect = graph()->NewNode(simplified()->StoreField(context_field), generator,
                             context, effect, control);
   effect = graph()->NewNode(simplified()->StoreField(continuation_field),
                             generator, continuation, effect, control);
+  effect = graph()->NewNode(simplified()->StoreField(input_field), generator,
+                            offset, effect, control);
 
   ReplaceWithValue(node, effect, effect, control);
   return Changed(effect);
 }
 
 Reduction JSTypedLowering::ReduceJSGeneratorRestoreContinuation(Node* node) {
   DCHECK_EQ(IrOpcode::kJSGeneratorRestoreContinuation, node->opcode());
   Node* generator = NodeProperties::GetValueInput(node, 0);
   Node* effect = NodeProperties::GetEffectInput(node);
   Node* control = NodeProperties::GetControlInput(node);
@@ skipping 227 matching lines @@
 }
 
 
 CompilationDependencies* JSTypedLowering::dependencies() const {
   return dependencies_;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8