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

src/objects-visiting-inl.h

Index: src/objects-visiting-inl.h
diff --git a/src/objects-visiting-inl.h b/src/objects-visiting-inl.h
index 010f3068a9e3ce1b7e493cb513e3c8df9fef3562..b1b0b391eeffcef81a210d4d612076a2d5caa339 100644
--- a/src/objects-visiting-inl.h
+++ b/src/objects-visiting-inl.h
@@ -897,7 +897,10 @@ void Code::CodeIterateBody(ObjectVisitor* v) {
   IteratePointer(v, kRelocationInfoOffset);
   IteratePointer(v, kHandlerTableOffset);
   IteratePointer(v, kDeoptimizationDataOffset);
-  IteratePointer(v, kTypeFeedbackInfoOffset);
+  if (v->weak_pointer_mode() == VISIT_WEAK_POINTERS || !is_optimized_code()) {
+    // In optimized code this field is a weak next_code_link.
+    IteratePointer(v, kTypeFeedbackInfoOffset);
+  }
   IteratePointer(v, kConstantPoolOffset);
 
   RelocIterator it(this, mode_mask);
@@ -929,9 +932,13 @@ void Code::CodeIterateBody(Heap* heap) {
   StaticVisitor::VisitPointer(
       heap,
       reinterpret_cast<Object**>(this->address() + kDeoptimizationDataOffset));
-  StaticVisitor::VisitPointer(
-      heap,
-      reinterpret_cast<Object**>(this->address() + kTypeFeedbackInfoOffset));
+  if (StaticVisitor::weak_pointer_mode() == VISIT_WEAK_POINTERS ||
+      !is_optimized_code()) {

[Michael Starzinger, 2014/03/04 12:31:12]

As discussed offline: AFAICT, currently we can afford to not have the fields
overlap as the padding is big enough on 32bit and 64bit architectures. So
"un-overlapping" them woukd definitely make things easier to read.

[titzer, 2014/03/05 08:58:02]

+1 unoverlap. I am sorry for overlapping them in the first place.

[ulan, 2014/03/06 11:13:32]

Nope, it is my fault. I remember introducing this field and overlapping it.
Sorry for that.

[ulan, 2014/03/06 11:13:32]

Done.

+    // In optimized code this field is a weak next_code_link.
+    StaticVisitor::VisitPointer(
+        heap,
+        reinterpret_cast<Object**>(this->address() + kTypeFeedbackInfoOffset));
+  }
   StaticVisitor::VisitPointer(
       heap,
       reinterpret_cast<Object**>(this->address() + kConstantPoolOffset));