Reland "Fix memory leak caused by field type in descriptor array."

src/objects-debug.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/heap/objects-visiting.h"
 #include "src/jsregexp.h"
@@ skipping 271 matching lines @@
         if (IsUnboxedDoubleField(index)) {
           DCHECK(r.IsDouble());
           continue;
         }
         Object* value = RawFastPropertyAt(index);
         if (r.IsDouble()) DCHECK(value->IsMutableHeapNumber());
         if (value->IsUninitialized()) continue;
         if (r.IsSmi()) DCHECK(value->IsSmi());
         if (r.IsHeapObject()) DCHECK(value->IsHeapObject());
         HeapType* field_type = descriptors->GetFieldType(i);
+        bool type_is_none = field_type->Is(HeapType::None());
+        bool type_is_any = field_type->Is(HeapType::Any());

[Jakob Kummerow, 2015/04/11 12:00:58]

Shouldn't this be the other way round, i.e. HeapType::Any()->Is(field_type) ?
AKAIF "t->Is(Any)" will be true for every type t, whereas "Any->Is(t)" is only
true when t == Any.

         if (r.IsNone()) {
-          CHECK(field_type->Is(HeapType::None()));
-        } else if (!HeapType::Any()->Is(field_type)) {
+          CHECK(type_is_none);
+        } else if (!type_is_any && !(type_is_none && r.IsHeapObject())) {
           CHECK(!field_type->NowStable() || field_type->NowContains(value));
         }
       }
     }
   }
 
   // If a GC was caused while constructing this object, the elements
   // pointer may point to a one pointer filler map.
   if (ElementsAreSafeToExamine()) {
     CHECK_EQ((map()->has_fast_smi_or_object_elements() ||
@@ skipping 964 matching lines @@
                          ? it.rinfo()->target_cell()
                          : it.rinfo()->target_object();
     CHECK(!CanLeak(target, heap, skip_weak_cell));
   }
 }
 
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal