[generators] Implement %GeneratorGetSourcePosition.

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index ab8e0133b4481174a746ef8797146206034391f2..918ce5e31852b195edb1f74475fb99b3479bc2ac 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -1727,6 +1727,7 @@ 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);
@@ -1736,12 +1737,13 @@ Reduction JSTypedLowering::ReduceJSGeneratorStore(Node* node) {
   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);
@@ -1751,6 +1753,8 @@ Reduction JSTypedLowering::ReduceJSGeneratorStore(Node* node) {
                             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);