Use weak cells in dependent code.

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.
 //
@@ skipping 4702 matching lines @@
   if (length() == 0) return 0;
   return Smi::cast(get(group))->value();
 }
 
 
 void DependentCode::set_number_of_entries(DependencyGroup group, int value) {
   set(group, Smi::FromInt(value));
 }
 
 
-bool DependentCode::is_code_at(int i) {
-  return get(kCodesStartIndex + i)->IsCode();
-}
-
-Code* DependentCode::code_at(int i) {
-  return Code::cast(get(kCodesStartIndex + i));
-}
-
-
-CompilationInfo* DependentCode::compilation_info_at(int i) {
-  return reinterpret_cast<CompilationInfo*>(
-      Foreign::cast(get(kCodesStartIndex + i))->foreign_address());
-}
-
-
 void DependentCode::set_object_at(int i, Object* object) {
   set(kCodesStartIndex + i, object);
 }
 
 
 Object* DependentCode::object_at(int i) {
   return get(kCodesStartIndex + i);
 }
 
 
-Object** DependentCode::slot_at(int i) {
-  return RawFieldOfElementAt(kCodesStartIndex + i);
-}
-
-
 void DependentCode::clear_at(int i) {
   set_undefined(kCodesStartIndex + i);
 }
 
 
 void DependentCode::copy(int from, int to) {
   set(kCodesStartIndex + to, get(kCodesStartIndex + from));
 }
 
 
@@ skipping 2755 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_