Add map-based read barrier to WeakCell

src/isolate.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 <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
 #include "src/v8.h"
@@ skipping 2586 matching lines @@
       new_length += 2;
     }
   }
   PrintF("%d detached contexts are collected out of %d\n", length - new_length,
          length);
   for (int i = 0; i < new_length; i += 2) {
     int mark_sweeps = Smi::cast(detached_contexts->get(i))->value();
     WeakCell* cell = WeakCell::cast(detached_contexts->get(i + 1));
     if (mark_sweeps > 3) {
       PrintF("detached context 0x%p\n survived %d GCs (leak?)\n",
-             static_cast<void*>(cell->value()), mark_sweeps);
+             static_cast<void*>(cell->ValueNoReadBarrier()), mark_sweeps);
     }
   }
   if (length == new_length) {
     heap()->set_detached_contexts(heap()->empty_fixed_array());
   } else {
     heap()->RightTrimFixedArray<Heap::FROM_GC>(*detached_contexts,
                                                length - new_length);
   }
 }
 
@@ skipping 15 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal