[turbofan] Flatten cons strings before embedding them into optimized code.

src/compiler/js-frame-specialization.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-frame-specialization.h"
 
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
 #include "src/frames-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 Reduction JSFrameSpecialization::Reduce(Node* node) {
   switch (node->opcode()) {
     case IrOpcode::kOsrValue:
       return ReduceOsrValue(node);
     case IrOpcode::kParameter:
       return ReduceParameter(node);
     default:
       break;
   }
   return NoChange();
 }
 
 
 Reduction JSFrameSpecialization::ReduceOsrValue(Node* node) {
   DCHECK_EQ(IrOpcode::kOsrValue, node->opcode());
-  DisallowHeapAllocation no_gc;
-  Object* object;
+  Handle<Object> value;
   int const index = OpParameter<int>(node);
   int const parameters_count = frame()->ComputeParametersCount() + 1;
   if (index == Linkage::kOsrContextSpillSlotIndex) {
-    object = frame()->context();
+    value = handle(frame()->context(), isolate());
   } else if (index >= parameters_count) {
-    object = frame()->GetExpression(index - parameters_count);
+    value = handle(frame()->GetExpression(index - parameters_count), isolate());
   } else {
     // The OsrValue index 0 is the receiver.
-    object = index ? frame()->GetParameter(index - 1) : frame()->receiver();
+    value =
+        handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
+               isolate());
   }
-  return Replace(jsgraph()->Constant(handle(object, isolate())));
+  return Replace(jsgraph()->Constant(value));
 }
 
 
 Reduction JSFrameSpecialization::ReduceParameter(Node* node) {
   DCHECK_EQ(IrOpcode::kParameter, node->opcode());
-  DisallowHeapAllocation no_gc;
-  Object* object;
+  Handle<Object> value;
   int const index = ParameterIndexOf(node->op());
   int const parameters_count = frame()->ComputeParametersCount() + 1;
   if (index == Linkage::kJSCallClosureParamIndex) {
     // The Parameter index references the closure.
-    object = frame()->function();
+    value = handle(frame()->function(), isolate());
   } else if (index == Linkage::GetJSCallArgCountParamIndex(parameters_count)) {
     // The Parameter index references the parameter count.
-    object = Smi::FromInt(parameters_count - 1);
+    value = handle(Smi::FromInt(parameters_count - 1), isolate());
   } else if (index == Linkage::GetJSCallContextParamIndex(parameters_count)) {
     // The Parameter index references the context.
-    object = frame()->context();
+    value = handle(frame()->context(), isolate());
   } else {
     // The Parameter index 0 is the receiver.
-    object = index ? frame()->GetParameter(index - 1) : frame()->receiver();
+    value =
+        handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
+               isolate());
   }
-  return Replace(jsgraph()->Constant(handle(object, isolate())));
+  return Replace(jsgraph()->Constant(value));
 }
 
 
 Isolate* JSFrameSpecialization::isolate() const { return jsgraph()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8