Introduce IsUndefined(Isolate*) and IsTheHole(Isolate*)

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 3cd0553d58e1cfe90604e1cf45f1213c4e9ccd75..887fed085faa1013a26302a359cfcf44c33170ea 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1064,6 +1064,9 @@ class Object {
   STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
 #undef DECLARE_STRUCT_PREDICATE
 
+  INLINE(bool IsTheHole(Isolate* isolate) const);
+  INLINE(bool IsUndefined(Isolate* isolate) const);
+
   // ES6, section 7.2.2 IsArray.  NOT to be confused with %_IsArray.
   MUST_USE_RESULT static Maybe<bool> IsArray(Handle<Object> object);
 
@@ -1560,6 +1563,9 @@ class HeapObject: public Object {
   STRUCT_LIST(DECLARE_STRUCT_PREDICATE)
 #undef DECLARE_STRUCT_PREDICATE
 
+  INLINE(bool IsTheHole(Isolate* isolate) const);
+  INLINE(bool IsUndefined(Isolate* isolate) const);
+
   // Converts an address to a HeapObject pointer.
   static inline HeapObject* FromAddress(Address address) {
     DCHECK_TAG_ALIGNED(address);
@@ -3870,7 +3876,7 @@ class OrderedHashTable: public FixedArray {
   int KeyToFirstEntry(Object* key) {
     Object* hash = key->GetHash();
     // If the object does not have an identity hash, it was never used as a key
-    if (hash->IsUndefined()) return kNotFound;
+    if (hash->IsUndefined(GetIsolate())) return kNotFound;

[ulan, 2016/06/01 19:01:44]

Before it was doing 2 loads
hash->map->instance_type

Now it is doing 4 loads
hash->page->heap->isolate->heap->undefined_value

     return HashToEntry(Smi::cast(hash)->value());
   }
 
@@ -3879,7 +3885,7 @@ class OrderedHashTable: public FixedArray {
     return Smi::cast(next_entry)->value();
   }
 
-  // use KeyAt(i)->IsTheHole() to determine if this is a deleted entry.
+  // use KeyAt(i)->IsTheHole(isolate) to determine if this is a deleted entry.
   Object* KeyAt(int entry) {
     DCHECK_LT(entry, this->UsedCapacity());
     return get(EntryToIndex(entry));