Add full TurboFan support for accessing SeqString contents.

src/compiler/js-intrinsic-lowering.cc

 
 // Copyright 2015 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/compiler/js-intrinsic-lowering.h"
 
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties.h"
@@ skipping 35 matching lines @@
     case Runtime::kInlineJSValueGetValue:
       return ReduceJSValueGetValue(node);
     case Runtime::kInlineMapGetInstanceType:
       return ReduceMapGetInstanceType(node);
     case Runtime::kInlineMathClz32:
       return ReduceMathClz32(node);
     case Runtime::kInlineMathFloor:
       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:
       break;
   }
   return NoChange();
 }
 
 
 Reduction JSIntrinsicLowering::ReduceConstructDouble(Node* node) {
@@ skipping 146 matching lines @@
   if (!machine()->HasFloat64RoundDown()) return NoChange();
   return Change(node, machine()->Float64RoundDown());
 }
 
 
 Reduction JSIntrinsicLowering::ReduceMathSqrt(Node* node) {
   return Change(node, machine()->Float64Sqrt());
 }
 
 
+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);
   Node* control = NodeProperties::GetControlInput(node);
   return Change(node, simplified()->LoadField(AccessBuilder::ForStringLength()),
                 value, effect, control);
 }
 
 
 Reduction JSIntrinsicLowering::ReduceValueOf(Node* node) {
@@ skipping 90 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSIntrinsicLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8