Use a dictionary-mode code cache on the map rather than a dual system.

src/ic/x64/ic-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/codegen.h"
 #include "src/ic/ic.h"
 #include "src/ic/ic-compiler.h"
 #include "src/ic/stub-cache.h"
@@ skipping 322 matching lines @@
   Register vector = LoadWithVectorDescriptor::VectorRegister();
   Register slot = LoadDescriptor::SlotRegister();
   DCHECK(!AreAliased(megamorphic_scratch, vector, slot));
   Handle<TypeFeedbackVector> dummy_vector =
       TypeFeedbackVector::DummyVector(masm->isolate());
   int slot_index = dummy_vector->GetIndex(
       FeedbackVectorSlot(TypeFeedbackVector::kDummyKeyedLoadICSlot));
   __ Move(vector, dummy_vector);
   __ Move(slot, Smi::FromInt(slot_index));
 
-  Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
-      Code::ComputeHandlerFlags(Code::LOAD_IC));
+  Code::Flags flags =
+      Code::RemoveHolderFromFlags(Code::ComputeHandlerFlags(Code::LOAD_IC));
   masm->isolate()->stub_cache()->GenerateProbe(masm, Code::KEYED_LOAD_IC, flags,
                                                receiver, key,
                                                megamorphic_scratch, no_reg);
   // Cache miss.
   GenerateMiss(masm);
 
   // Do a quick inline probe of the receiver's dictionary, if it
   // exists.
   __ bind(&probe_dictionary);
   // rbx: elements
@@ skipping 205 matching lines @@
   Register slot = VectorStoreICDescriptor::SlotRegister();
   // The handlers in the stub cache expect a vector and slot. Since we won't
   // change the IC from any downstream misses, a dummy vector can be used.
   Handle<TypeFeedbackVector> dummy_vector =
       TypeFeedbackVector::DummyVector(masm->isolate());
   int slot_index = dummy_vector->GetIndex(
       FeedbackVectorSlot(TypeFeedbackVector::kDummyKeyedStoreICSlot));
   __ Move(vector, dummy_vector);
   __ Move(slot, Smi::FromInt(slot_index));
 
-  Code::Flags flags = Code::RemoveTypeAndHolderFromFlags(
-      Code::ComputeHandlerFlags(Code::STORE_IC));
+  Code::Flags flags =
+      Code::RemoveHolderFromFlags(Code::ComputeHandlerFlags(Code::STORE_IC));
   masm->isolate()->stub_cache()->GenerateProbe(masm, Code::STORE_IC, flags,
                                                receiver, key, r9, no_reg);
   // Cache miss.
   __ jmp(&miss);
 
   // Extra capacity case: Check if there is extra capacity to
   // perform the store and update the length. Used for adding one
   // element to the array by writing to array[array.length].
   __ bind(&extra);
   // receiver is a JSArray.
@@ skipping 263 matching lines @@
   Condition cc =
       (check == ENABLE_INLINED_SMI_CHECK)
           ? (*jmp_address == Assembler::kJncShortOpcode ? not_zero : zero)
           : (*jmp_address == Assembler::kJnzShortOpcode ? not_carry : carry);
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64