Encapsulate megamorphic load/tail-call in hydrogen

src/code-stubs-hydrogen.cc

 // Copyright 2012 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/v8.h"
 
 #include "src/code-stubs.h"
 #include "src/field-index.h"
 #include "src/hydrogen.h"
 #include "src/lithium.h"
@@ skipping 1794 matching lines @@
 HValue* CodeStubGraphBuilder<VectorKeyedLoadStub>::BuildCodeStub() {
   HValue* receiver = GetParameter(VectorLoadICDescriptor::kReceiverIndex);
   Add<HDeoptimize>("Always deopt", Deoptimizer::EAGER);
   return receiver;
 }
 
 
 Handle<Code> VectorKeyedLoadStub::GenerateCode() {
   return DoGenerateCode(this);
 }
+
+
+Handle<Code> MegamorphicLoadStub::GenerateCode() {
+  return DoGenerateCode(this);
+}
+
+
+template <>
+HValue* CodeStubGraphBuilder<MegamorphicLoadStub>::BuildCodeStub() {
+  // The return address is on the stack.
+  HValue* receiver = GetParameter(LoadDescriptor::kReceiverIndex);
+  HValue* name = GetParameter(LoadDescriptor::kNameIndex);
+
+  // Probe the stub cache.
+  Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
+      Code::ComputeHandlerFlags(Code::LOAD_IC));
+  Add<HTailCallThroughMegamorphicCache>(receiver, name, flags);
+
+  // We never continue.
+  return graph()->GetConstant0();
+}
 } }  // namespace v8::internal