Reland r19897 "Fix memory leak caused by treating Code::next_code_link as strong in marker.

src/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1757 matching lines @@
   }
 
   // Terminate the list if there is one or more elements.
   if (tail != NULL) {
     WeakListVisitor<T>::SetWeakNext(tail, undefined);
   }
   return head;
 }
 
 
+template <class T>
+static void ClearWeakList(Heap* heap,
+                          Object* list) {
+  Object* undefined = heap->undefined_value();
+  while (list != undefined) {
+    T* candidate = reinterpret_cast<T*>(list);
+    list = WeakListVisitor<T>::WeakNext(candidate);
+    WeakListVisitor<T>::SetWeakNext(candidate, undefined);
+  }
+}
+
+
 template<>
 struct WeakListVisitor<JSFunction> {
   static void SetWeakNext(JSFunction* function, Object* next) {
     function->set_next_function_link(next);
   }
 
   static Object* WeakNext(JSFunction* function) {
     return function->next_function_link();
   }
 
@@ skipping 73 matching lines @@
 
     if (record_slots) {
       // Record the updated slot if necessary.
       Object** head_slot = HeapObject::RawField(
           context, FixedArray::SizeFor(index));
       heap->mark_compact_collector()->RecordSlot(
           head_slot, head_slot, list_head);
     }
   }
 
-  static void VisitPhantomObject(Heap*, Context*) {
+  static void VisitPhantomObject(Heap* heap, Context* context) {
+    ClearWeakList<JSFunction>(heap,
+        context->get(Context::OPTIMIZED_FUNCTIONS_LIST));
+    ClearWeakList<Code>(heap, context->get(Context::OPTIMIZED_CODE_LIST));
+    ClearWeakList<Code>(heap, context->get(Context::DEOPTIMIZED_CODE_LIST));
   }
 
   static int WeakNextOffset() {
     return FixedArray::SizeFor(Context::NEXT_CONTEXT_LINK);
   }
 };
 
 
 void Heap::ProcessWeakReferences(WeakObjectRetainer* retainer) {
   // We don't record weak slots during marking or scavenges.
@@ skipping 2237 matching lines @@
   ASSERT(!isolate_->code_range()->exists() ||
       isolate_->code_range()->contains(code->address()));
   code->set_instruction_size(desc.instr_size);
   code->set_relocation_info(reloc_info);
   code->set_flags(flags);
   code->set_raw_kind_specific_flags1(0);
   code->set_raw_kind_specific_flags2(0);
   code->set_is_crankshafted(crankshafted);
   code->set_deoptimization_data(empty_fixed_array(), SKIP_WRITE_BARRIER);
   code->set_raw_type_feedback_info(undefined_value());
+  code->set_next_code_link(undefined_value());
   code->set_handler_table(empty_fixed_array(), SKIP_WRITE_BARRIER);
   code->set_gc_metadata(Smi::FromInt(0));
   code->set_ic_age(global_ic_age_);
   code->set_prologue_offset(prologue_offset);
   if (code->kind() == Code::OPTIMIZED_FUNCTION) {
     code->set_marked_for_deoptimization(false);
   }
 
   if (FLAG_enable_ool_constant_pool) {
     desc.origin->PopulateConstantPool(constant_pool);
@@ skipping 3672 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   OS::MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   OS::MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 
 } }  // namespace v8::internal