Introduce FieldIndex to unify and abstract property/field offset

src/objects-inl.h

 // 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
 
 #ifndef V8_OBJECTS_INL_H_
 #define V8_OBJECTS_INL_H_
 
 #include "src/base/atomicops.h"
 #include "src/elements.h"
 #include "src/objects.h"
 #include "src/contexts.h"
 #include "src/conversions-inl.h"
+#include "src/field-index-inl.h"
 #include "src/heap.h"
 #include "src/isolate.h"
 #include "src/heap-inl.h"
 #include "src/property.h"
 #include "src/spaces.h"
 #include "src/store-buffer.h"
 #include "src/v8memory.h"
 #include "src/factory.h"
 #include "src/incremental-marking.h"
 #include "src/transitions-inl.h"
@@ skipping 1908 matching lines @@
   // properties are at the end of the object. Therefore there is no need
   // to adjust the index here.
   int offset = GetHeaderSize() + (kPointerSize * index);
   WRITE_FIELD(this, offset, value);
 }
 
 
 // Access fast-case object properties at index. The use of these routines
 // is needed to correctly distinguish between properties stored in-object and
 // properties stored in the properties array.
-Object* JSObject::RawFastPropertyAt(int index) {
-  // Adjust for the number of properties stored in the object.
-  index -= map()->inobject_properties();
-  if (index < 0) {
-    int offset = map()->instance_size() + (index * kPointerSize);
-    return READ_FIELD(this, offset);
+Object* JSObject::RawFastPropertyAt(FieldIndex index) {
+  if (index.is_inobject()) {
+    return READ_FIELD(this, index.offset());
   } else {
-    ASSERT(index < properties()->length());
-    return properties()->get(index);
+    return properties()->get(index.outobject_array_index());
   }
 }
 
 
-void JSObject::FastPropertyAtPut(int index, Object* value) {
-  // Adjust for the number of properties stored in the object.
-  index -= map()->inobject_properties();
-  if (index < 0) {
-    int offset = map()->instance_size() + (index * kPointerSize);
+void JSObject::FastPropertyAtPut(FieldIndex index, Object* value) {
+  if (index.is_inobject()) {
+    int offset = index.offset();
     WRITE_FIELD(this, offset, value);
     WRITE_BARRIER(GetHeap(), this, offset, value);
   } else {
-    ASSERT(index < properties()->length());
-    properties()->set(index, value);
+    properties()->set(index.outobject_array_index(), value);
   }
 }
 
 
 int JSObject::GetInObjectPropertyOffset(int index) {
   return map()->GetInObjectPropertyOffset(index);
 }
 
 
 Object* JSObject::InObjectPropertyAt(int index) {
@@ skipping 2088 matching lines @@
 
 
 int Map::pre_allocated_property_fields() {
   return READ_BYTE_FIELD(this, kPreAllocatedPropertyFieldsOffset);
 }
 
 
 int Map::GetInObjectPropertyOffset(int index) {
   // Adjust for the number of properties stored in the object.
   index -= inobject_properties();
-  ASSERT(index < 0);
+  ASSERT(index <= 0);
   return instance_size() + (index * kPointerSize);
 }
 
 
 int HeapObject::SizeFromMap(Map* map) {
   int instance_size = map->instance_size();
   if (instance_size != kVariableSizeSentinel) return instance_size;
   // Only inline the most frequent cases.
   InstanceType instance_type = map->instance_type();
   if (instance_type == FIXED_ARRAY_TYPE) {
@@ skipping 2901 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_