Change RecordSlot interface. Make it more robust by replacing anchor slot with actual object.

src/heap/objects-visiting.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.
 
 #ifndef V8_OBJECTS_VISITING_H_
 #define V8_OBJECTS_VISITING_H_
 
 #include "src/allocation.h"
 #include "src/layout-descriptor.h"
 
@@ skipping 197 matching lines @@
     if (!FLAG_unbox_double_fields || object->map()->HasFastPointerLayout()) {
       IterateRawPointers(heap, object, start_offset, end_offset);
     } else {
       IterateBodyUsingLayoutDescriptor(heap, object, start_offset, end_offset);
     }
   }
 
  private:
   INLINE(static void IterateRawPointers(Heap* heap, HeapObject* object,
                                         int start_offset, int end_offset)) {
-    StaticVisitor::VisitPointers(heap,
+    StaticVisitor::VisitPointers(heap, object,
                                  HeapObject::RawField(object, start_offset),
                                  HeapObject::RawField(object, end_offset));
   }
 
   static void IterateBodyUsingLayoutDescriptor(Heap* heap, HeapObject* object,
                                                int start_offset,
                                                int end_offset) {
     DCHECK(FLAG_unbox_double_fields);
     DCHECK(IsAligned(start_offset, kPointerSize) &&
            IsAligned(end_offset, kPointerSize));
@@ skipping 61 matching lines @@
 // inlining and specialization of StaticVisitor::VisitPointers methods).
 template <typename StaticVisitor>
 class StaticNewSpaceVisitor : public StaticVisitorBase {
  public:
   static void Initialize();
 
   INLINE(static int IterateBody(Map* map, HeapObject* obj)) {
     return table_.GetVisitor(map)(map, obj);
   }
 
-  INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) {
+  INLINE(static void VisitPointers(Heap* heap, HeapObject* object,

[Michael Starzinger, 2015/08/04 15:20:13]

Is this change for the StaticNewSpaceVisitor really necessary? This one should
never be applied to LO-space objects. The StaticNewSpaceVisitor is independent
from the StaticMarkingVisitor and hence its interface can be (and already is)
out of sync.

[Hannes Payer (out of office), 2015/08/04 16:16:21]

Unfortunatly, BodyVisitorBase is used by both. We have to add it also to the new
space visitor.

+                                   Object** start, Object** end)) {
     for (Object** p = start; p < end; p++) StaticVisitor::VisitPointer(heap, p);
   }
 
  private:
   INLINE(static int VisitJSFunction(Map* map, HeapObject* object)) {
     Heap* heap = map->GetHeap();
-    VisitPointers(heap,
+    VisitPointers(heap, object,
                   HeapObject::RawField(object, JSFunction::kPropertiesOffset),
                   HeapObject::RawField(object, JSFunction::kCodeEntryOffset));
 
     // Don't visit code entry. We are using this visitor only during scavenges.
 
     VisitPointers(
-        heap, HeapObject::RawField(object,
-                                   JSFunction::kCodeEntryOffset + kPointerSize),
+        heap, object, HeapObject::RawField(
+                          object, JSFunction::kCodeEntryOffset + kPointerSize),
         HeapObject::RawField(object, JSFunction::kNonWeakFieldsEndOffset));
     return JSFunction::kSize;
   }
 
   INLINE(static int VisitByteArray(Map* map, HeapObject* object)) {
     return reinterpret_cast<ByteArray*>(object)->ByteArraySize();
   }
 
   INLINE(static int VisitBytecodeArray(Map* map, HeapObject* object)) {
     return reinterpret_cast<BytecodeArray*>(object)->BytecodeArraySize();
@@ skipping 77 matching lines @@
 class StaticMarkingVisitor : public StaticVisitorBase {
  public:
   static void Initialize();
 
   INLINE(static void IterateBody(Map* map, HeapObject* obj)) {
     table_.GetVisitor(map)(map, obj);
   }
 
   INLINE(static void VisitPropertyCell(Map* map, HeapObject* object));
   INLINE(static void VisitWeakCell(Map* map, HeapObject* object));
-  INLINE(static void VisitCodeEntry(Heap* heap, Address entry_address));
+  INLINE(static void VisitCodeEntry(Heap* heap, HeapObject* object,
+                                    Address entry_address));
   INLINE(static void VisitEmbeddedPointer(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitCell(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitDebugTarget(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitCodeTarget(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitCodeAgeSequence(Heap* heap, RelocInfo* rinfo));
   INLINE(static void VisitExternalReference(RelocInfo* rinfo)) {}
   INLINE(static void VisitInternalReference(RelocInfo* rinfo)) {}
   INLINE(static void VisitRuntimeEntry(RelocInfo* rinfo)) {}
   // Skip the weak next code link in a code object.
   INLINE(static void VisitNextCodeLink(Heap* heap, Object** slot)) {}
@@ skipping 70 matching lines @@
 // the next element. Given the head of the list, this function removes dead
 // elements from the list and if requested records slots for next-element
 // pointers. The template parameter T is a WeakListVisitor that defines how to
 // access the next-element pointers.
 template <class T>
 Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer);
 }
 }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_VISITING_H_