[serializer] check that deserializer read the entire blob.

src/snapshot/deserializer.cc

 // Copyright 2016 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/snapshot/deserializer.h"
 
 #include "src/api.h"
 #include "src/assembler-inl.h"
 #include "src/bootstrapper.h"
 #include "src/external-reference-table.h"
@@ skipping 154 matching lines @@
       FlushICacheForNewCodeObjectsAndRecordEmbeddedObjects();
       result = Handle<HeapObject>(HeapObject::cast(root));
       isolate->heap()->RegisterReservationsForBlackAllocation(reservations_);
     }
     CommitPostProcessedObjects(isolate);
     return scope.CloseAndEscape(result);
   }
 }
 
 Deserializer::~Deserializer() {
-  // TODO(svenpanne) Re-enable this assertion when v8 initialization is fixed.
-  // DCHECK(source_.AtEOF());
 #ifdef DEBUG
+  // Do not perform checks if we aborted deserialization.
+  if (source_.position() == 0) return;
+  // Check that we only have padding bytes remaining.
+  while (source_.HasMore()) CHECK_EQ(kNop, source_.Get());
   for (int space = 0; space < kNumberOfPreallocatedSpaces; space++) {
     int chunk_index = current_chunk_[space];
     CHECK_EQ(reservations_[space].length(), chunk_index + 1);
     CHECK_EQ(reservations_[space][chunk_index].end, high_water_[space]);
   }
   CHECK_EQ(allocated_maps_.length(), next_map_index_);
 #endif  // DEBUG
 }
 
 // This is called on the roots.  It is the driver of the deserialization
@@ skipping 677 matching lines @@
 
       default:
         CHECK(false);
     }
   }
   CHECK_EQ(limit, current);
   return true;
 }
 }  // namespace internal
 }  // namespace v8