Move prototype metadata from internal properties to prototype maps

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 0e525d43346e7914478183c8b95c42ed1734ff17..df6fc68ff5047906095e262a0ccf3b17361e525c 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -4565,9 +4565,7 @@ void Map::set_unused_property_fields(int value) {
 }
 
 
-byte Map::bit_field() {
-  return READ_BYTE_FIELD(this, kBitFieldOffset);
-}
+byte Map::bit_field() const { return READ_BYTE_FIELD(this, kBitFieldOffset); }
 
 
 void Map::set_bit_field(byte value) {
@@ -4575,9 +4573,7 @@ void Map::set_bit_field(byte value) {
 }
 
 
-byte Map::bit_field2() {
-  return READ_BYTE_FIELD(this, kBitField2Offset);
-}
+byte Map::bit_field2() const { return READ_BYTE_FIELD(this, kBitField2Offset); }
 
 
 void Map::set_bit_field2(byte value) {
@@ -4640,7 +4636,7 @@ void Map::set_is_prototype_map(bool value) {
   set_bit_field2(IsPrototypeMapBits::update(bit_field2(), value));
 }
 
-bool Map::is_prototype_map() {
+bool Map::is_prototype_map() const {
   return IsPrototypeMapBits::decode(bit_field2());
 }
 
@@ -5334,7 +5330,7 @@ void Map::set_bit_field3(uint32_t bits) {
 }
 
 
-uint32_t Map::bit_field3() {
+uint32_t Map::bit_field3() const {
   return READ_UINT32_FIELD(this, kBitField3Offset);
 }
 
@@ -5376,7 +5372,21 @@ Map* Map::ElementsTransitionMap() {
 }
 
 
-ACCESSORS(Map, raw_transitions, Object, kTransitionsOffset)
+ACCESSORS(Map, raw_transitions, Object, kTransitionsOrPrototypeInfoOffset)
+
+
+Object* Map::prototype_info() const {
+  DCHECK(is_prototype_map());
+  return READ_FIELD(this, Map::kTransitionsOrPrototypeInfoOffset);
+}
+
+
+void Map::set_prototype_info(Object* value, WriteBarrierMode mode) {
+  DCHECK(is_prototype_map());
+  WRITE_FIELD(this, Map::kTransitionsOrPrototypeInfoOffset, value);
+  CONDITIONAL_WRITE_BARRIER(
+      GetHeap(), this, Map::kTransitionsOrPrototypeInfoOffset, value, mode);
+}
 
 
 void Map::SetBackPointer(Object* value, WriteBarrierMode mode) {
@@ -5436,6 +5446,9 @@ ACCESSORS(ExecutableAccessorInfo, data, Object, kDataOffset)
 
 ACCESSORS(Box, value, Object, kValueOffset)
 
+ACCESSORS(PrototypeInfo, prototype_users, Object, kPrototypeUsersOffset)
+ACCESSORS(PrototypeInfo, validity_cell, Object, kValidityCellOffset)
+
 ACCESSORS(AccessorPair, getter, Object, kGetterOffset)
 ACCESSORS(AccessorPair, setter, Object, kSetterOffset)