Add full TurboFan support for accessing SeqString contents.

src/compiler/js-intrinsic-lowering.cc

Index: src/compiler/js-intrinsic-lowering.cc
diff --git a/src/compiler/js-intrinsic-lowering.cc b/src/compiler/js-intrinsic-lowering.cc
index 5a03f5dbbd69c39ce274d8934bf41b36a4d7db9f..31100293329cd91fdbbebc119836d8f23e7316d4 100644
--- a/src/compiler/js-intrinsic-lowering.cc
+++ b/src/compiler/js-intrinsic-lowering.cc
@@ -53,8 +53,16 @@ Reduction JSIntrinsicLowering::Reduce(Node* node) {
       return ReduceMathFloor(node);
     case Runtime::kInlineMathSqrt:
       return ReduceMathSqrt(node);
+    case Runtime::kInlineOneByteSeqStringGetChar:
+      return ReduceSeqStringGetChar(node, String::ONE_BYTE_ENCODING);
+    case Runtime::kInlineOneByteSeqStringSetChar:
+      return ReduceSeqStringSetChar(node, String::ONE_BYTE_ENCODING);
     case Runtime::kInlineStringGetLength:
       return ReduceStringGetLength(node);
+    case Runtime::kInlineTwoByteSeqStringGetChar:
+      return ReduceSeqStringGetChar(node, String::TWO_BYTE_ENCODING);
+    case Runtime::kInlineTwoByteSeqStringSetChar:
+      return ReduceSeqStringSetChar(node, String::TWO_BYTE_ENCODING);
     case Runtime::kInlineValueOf:
       return ReduceValueOf(node);
     default:
@@ -221,6 +229,42 @@ Reduction JSIntrinsicLowering::ReduceMathSqrt(Node* node) {
 }
 
 
+Reduction JSIntrinsicLowering::ReduceSeqStringGetChar(
+    Node* node, String::Encoding encoding) {
+  Node* effect = NodeProperties::GetEffectInput(node);
+  Node* control = NodeProperties::GetControlInput(node);
+  node->set_op(
+      simplified()->LoadElement(AccessBuilder::ForSeqStringChar(encoding)));
+  node->ReplaceInput(2, effect);
+  node->ReplaceInput(3, control);
+  node->TrimInputCount(4);
+  NodeProperties::ReplaceWithValue(node, node, node);
+  return Changed(node);
+}
+
+
+Reduction JSIntrinsicLowering::ReduceSeqStringSetChar(
+    Node* node, String::Encoding encoding) {
+  // Note: The intrinsic has a strange argument order, so we need to reshuffle.
+  Node* index = NodeProperties::GetValueInput(node, 0);
+  Node* chr = NodeProperties::GetValueInput(node, 1);
+  Node* string = NodeProperties::GetValueInput(node, 2);
+  Node* effect = NodeProperties::GetEffectInput(node);
+  Node* control = NodeProperties::GetControlInput(node);
+  node->set_op(
+      simplified()->StoreElement(AccessBuilder::ForSeqStringChar(encoding)));
+  node->ReplaceInput(0, string);
+  node->ReplaceInput(1, index);
+  node->ReplaceInput(2, chr);
+  node->ReplaceInput(3, effect);
+  node->ReplaceInput(4, control);
+  node->TrimInputCount(5);
+  NodeProperties::RemoveBounds(node);
+  NodeProperties::ReplaceWithValue(node, node, node);

[Michael Starzinger, 2015/03/25 17:41:55]

Let's just use "string" as the second argument to ReplaceWithValue here, this is
more correct and robust in general and also solves the problem with the missing
return value in the tests. Because it would be way to easy to write such a
construct by accident in the builtin JavaScript code. The more I think about it,
the more it feels like a good rule-of-thumb to let every intrinsic have a
default return value just to keep the graph structurally intact.

[Sven Panne, 2015/03/26 08:02:34]

Done.

+  return Changed(node);
+}
+
+
 Reduction JSIntrinsicLowering::ReduceStringGetLength(Node* node) {
   Node* value = NodeProperties::GetValueInput(node, 0);
   Node* effect = NodeProperties::GetEffectInput(node);