Fast body iteration for objects without unboxed fields.

src/objects-body-descriptors.h

Index: src/objects-body-descriptors.h
diff --git a/src/objects-body-descriptors.h b/src/objects-body-descriptors.h
index 3efaae9c9785b63c926b0acc548b893057bb83ca..9f080eb7551bd6e2cbe2c6ea42dca3cd7c91a7da 100644
--- a/src/objects-body-descriptors.h
+++ b/src/objects-body-descriptors.h
@@ -82,7 +82,7 @@ class FixedBodyDescriptor final : public BodyDescriptorBase {
 
   template <typename ObjectVisitor>
   static inline void IterateBody(HeapObject* obj, ObjectVisitor* v) {
-    IterateBodyImpl(obj, start_offset, end_offset, v);
+    IteratePointers(obj, start_offset, end_offset, v);
   }
 
   template <typename ObjectVisitor>
@@ -94,7 +94,7 @@ class FixedBodyDescriptor final : public BodyDescriptorBase {
   template <typename StaticVisitor>
   static inline void IterateBody(HeapObject* obj) {
     Heap* heap = obj->GetHeap();
-    IterateBodyImpl<StaticVisitor>(heap, obj, start_offset, end_offset);
+    IteratePointers<StaticVisitor>(heap, obj, start_offset, end_offset);
   }
 
   template <typename StaticVisitor>
@@ -113,20 +113,19 @@ class FlexibleBodyDescriptor final : public BodyDescriptorBase {
   static const int kStartOffset = start_offset;
 
   static bool IsValidSlot(HeapObject* obj, int offset) {
-    if (offset < kStartOffset) return false;
-    return IsValidSlotImpl(obj, offset);
+    return (offset >= kStartOffset);
   }
 
   template <typename ObjectVisitor>
   static inline void IterateBody(HeapObject* obj, int object_size,
                                  ObjectVisitor* v) {
-    IterateBodyImpl(obj, start_offset, object_size, v);
+    IteratePointers(obj, start_offset, object_size, v);
   }
 
   template <typename StaticVisitor>
   static inline void IterateBody(HeapObject* obj, int object_size) {
     Heap* heap = obj->GetHeap();
-    IterateBodyImpl<StaticVisitor>(heap, obj, start_offset, object_size);
+    IteratePointers<StaticVisitor>(heap, obj, start_offset, object_size);
   }
 
   static inline int SizeOf(Map* map, HeapObject* object);