Add map-based read barrier to WeakCell

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index bccce299bddcd80a161b8771b7cccc7e51871642..798453128836e8546024bb96c43e6252638afa25 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -536,7 +536,7 @@ HValue* CodeStubGraphBuilder<CreateWeakCellStub>::BuildCodeStub() {
   HInstruction* object =
       Add<HAllocate>(size, HType::JSObject(), TENURED, JS_OBJECT_TYPE);
 
-  Handle<Map> weak_cell_map = isolate()->factory()->weak_cell_map();
+  Handle<Map> weak_cell_map = isolate()->factory()->used_weak_cell_map();
   AddStoreMapConstant(object, weak_cell_map);
 
   HInstruction* value = GetParameter(CreateWeakCellDescriptor::kValueIndex);
@@ -1340,8 +1340,8 @@ HValue* CodeStubGraphBuilder<StoreGlobalStub>::BuildCodeInitializedStub() {
         Add<HLoadNamedField>(proxy_map, nullptr, HObjectAccess::ForPrototype());
     Handle<Map> placeholder_map = isolate()->factory()->meta_map();
     HValue* cell = Add<HConstant>(Map::WeakCellForMap(placeholder_map));
-    HValue* expected_map =
-        Add<HLoadNamedField>(cell, nullptr, HObjectAccess::ForWeakCellValue());
+    HValue* expected_map = Add<HLoadNamedField>(
+        cell, nullptr, HObjectAccess::ForWeakCellValueComparison());
     HValue* map =
         Add<HLoadNamedField>(global, nullptr, HObjectAccess::ForMap());
     IfBuilder map_check(this);
@@ -2088,8 +2088,8 @@ void CodeStubGraphBuilderBase::HandleArrayCases(HValue* array, HValue* receiver,
       Add<HLoadKeyed>(array, start, nullptr, FAST_ELEMENTS, ALLOW_RETURN_HOLE);
   // Load the weak cell value. It may be Smi(0), or a map. Compare nonetheless
   // against the receiver_map.
-  HValue* array_map = Add<HLoadNamedField>(weak_cell, nullptr,
-                                           HObjectAccess::ForWeakCellValue());
+  HValue* array_map = Add<HLoadNamedField>(
+      weak_cell, nullptr, HObjectAccess::ForWeakCellValueComparison());
 
   IfBuilder if_correct_map(this);
   if_correct_map.If<HCompareObjectEqAndBranch>(receiver_map, array_map);
@@ -2108,7 +2108,7 @@ void CodeStubGraphBuilderBase::HandleArrayCases(HValue* array, HValue* receiver,
       HValue* weak_cell = Add<HLoadKeyed>(array, key, nullptr, FAST_ELEMENTS,
                                           ALLOW_RETURN_HOLE);
       HValue* array_map = Add<HLoadNamedField>(
-          weak_cell, nullptr, HObjectAccess::ForWeakCellValue());
+          weak_cell, nullptr, HObjectAccess::ForWeakCellValueComparison());
       IfBuilder if_correct_poly_map(this);
       if_correct_poly_map.If<HCompareObjectEqAndBranch>(receiver_map,
                                                         array_map);