[turbofan] Avoid unnecessary write barriers and improve code generation.

src/heap/heap.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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 4362 matching lines @@
     case LO_SPACE:
       return true;
     default:
       return false;
   }
 }
 
 
 bool Heap::RootIsImmortalImmovable(int root_index) {
   switch (root_index) {
-#define CASE(name)               \
-  case Heap::k##name##RootIndex: \
+#define IMMORTAL_IMMOVABLE_ROOT(name) case Heap::k##name##RootIndex:
+    IMMORTAL_IMMOVABLE_ROOT_LIST(IMMORTAL_IMMOVABLE_ROOT)
+#undef IMMORTAL_IMMOVABLE_ROOT
+#define INTERNALIZED_STRING(name, value) case Heap::k##name##RootIndex:
+    INTERNALIZED_STRING_LIST(INTERNALIZED_STRING)
+#undef INTERNALIZED_STRING
+#define STRING_TYPE(NAME, size, name, Name) case Heap::k##Name##MapRootIndex:
+    STRING_TYPE_LIST(STRING_TYPE)
+#undef STRING_TYPE
     return true;
-    IMMORTAL_IMMOVABLE_ROOT_LIST(CASE);
-#undef CASE
     default:
       return false;
   }
 }
 
 
 #ifdef VERIFY_HEAP
 void Heap::Verify() {
   CHECK(HasBeenSetUp());
   HandleScope scope(isolate());
@@ skipping 1790 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8