Add CHECKs when updating pointers from the slots and store buffers

src/heap/mark-compact.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/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 2866 matching lines @@
   }
 
   void VisitEmbeddedPointer(RelocInfo* rinfo) {
     DCHECK(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT);
     Object* target = rinfo->target_object();
     Object* old_target = target;
     VisitPointer(&target);
     // Avoid unnecessary changes that might unnecessary flush the instruction
     // cache.
     if (target != old_target) {
+      // TODO(jochen): Remove again after fixing http://crbug.com/452095
+      CHECK(target->IsHeapObject() == old_target->IsHeapObject());
       rinfo->set_target_object(target);
     }
   }
 
   void VisitCodeTarget(RelocInfo* rinfo) {
     DCHECK(RelocInfo::IsCodeTarget(rinfo->rmode()));
     Object* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
     Object* old_target = target;
     VisitPointer(&target);
     if (target != old_target) {
+      // TODO(jochen): Remove again after fixing http://crbug.com/452095
+      CHECK(target->IsHeapObject() == old_target->IsHeapObject());
       rinfo->set_target_address(Code::cast(target)->instruction_start());
     }
   }
 
   void VisitCodeAgeSequence(RelocInfo* rinfo) {
     DCHECK(RelocInfo::IsCodeAgeSequence(rinfo->rmode()));
     Object* stub = rinfo->code_age_stub();
     DCHECK(stub != NULL);
     VisitPointer(&stub);
     if (stub != rinfo->code_age_stub()) {
+      // TODO(jochen): Remove again after fixing http://crbug.com/452095
+      CHECK(stub->IsHeapObject() == rinfo->code_age_stub()->IsHeapObject());
       rinfo->set_code_age_stub(Code::cast(stub));
     }
   }
 
   void VisitDebugTarget(RelocInfo* rinfo) {
     DCHECK((RelocInfo::IsJSReturn(rinfo->rmode()) &&
             rinfo->IsPatchedReturnSequence()) ||
            (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
             rinfo->IsPatchedDebugBreakSlotSequence()));
     Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address());
     VisitPointer(&target);
+    // TODO(jochen): Remove again after fixing http://crbug.com/452095
+    CHECK(target->IsCode() &&
+          HAS_SMI_TAG(Code::cast(target)->instruction_start()));
     rinfo->set_call_address(Code::cast(target)->instruction_start());
   }
 
   static inline void UpdateSlot(Heap* heap, Object** slot) {
     Object* obj = reinterpret_cast<Object*>(
         base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
 
     if (!obj->IsHeapObject()) return;
 
     HeapObject* heap_obj = HeapObject::cast(obj);
@@ skipping 124 matching lines @@
 
 
 static void UpdatePointer(HeapObject** address, HeapObject* object) {
   MapWord map_word = object->map_word();
   // The store buffer can still contain stale pointers in dead large objects.
   // Ignore these pointers here.
   DCHECK(map_word.IsForwardingAddress() ||
          object->GetHeap()->lo_space()->FindPage(
              reinterpret_cast<Address>(address)) != NULL);
   if (map_word.IsForwardingAddress()) {
+    // TODO(jochen): Remove again after fixing http://crbug.com/452095
+    CHECK((*address)->IsHeapObject() ==
+          map_word.ToForwardingAddress()->IsHeapObject());
     // Update the corresponding slot.
     *address = map_word.ToForwardingAddress();
   }
 }
 
 
 static String* UpdateReferenceInExternalStringTableEntry(Heap* heap,
                                                          Object** p) {
   MapWord map_word = HeapObject::cast(*p)->map_word();
 
@@ skipping 1678 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }
 }  // namespace v8::internal