Ensure we can reliably check the cell for validity of global property

src/code-stubs-hydrogen.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/bailout-reason.h"
 #include "src/code-stubs.h"
 #include "src/field-index.h"
 #include "src/hydrogen.h"
@@ skipping 1320 matching lines @@
   StoreGlobalStub* stub = casted_stub();
   HParameter* value = GetParameter(StoreDescriptor::kValueIndex);
   if (stub->check_global()) {
     // Check that the map of the global has not changed: use a placeholder map
     // that will be replaced later with the global object's map.
     HParameter* proxy = GetParameter(StoreDescriptor::kReceiverIndex);
     HValue* proxy_map =
         Add<HLoadNamedField>(proxy, nullptr, HObjectAccess::ForMap());
     HValue* global =
         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* map =
-        Add<HLoadNamedField>(global, nullptr, HObjectAccess::ForMap());
-    IfBuilder map_check(this);
-    map_check.IfNot<HCompareObjectEqAndBranch>(expected_map, map);
-    map_check.ThenDeopt(Deoptimizer::kUnknownMap);
-    map_check.End();
+    HValue* current_global = Add<HLoadNamedField>(
+        context(), nullptr,
+        HObjectAccess::ForContextSlot(Context::GLOBAL_OBJECT_INDEX));
+    IfBuilder global_check(this);
+    global_check.IfNot<HCompareObjectEqAndBranch>(global, current_global);
+    global_check.ThenDeopt(Deoptimizer::kCrossContextGlobalStore);
+    global_check.End();
   }
 
   HValue* weak_cell = Add<HConstant>(isolate()->factory()->NewWeakCell(
       StoreGlobalStub::property_cell_placeholder(isolate())));
   HValue* cell = Add<HLoadNamedField>(weak_cell, nullptr,
                                       HObjectAccess::ForWeakCellValue());
+  Add<HCheckHeapObject>(cell);
   HObjectAccess access(HObjectAccess::ForCellPayload(isolate()));
   HValue* cell_contents = Add<HLoadNamedField>(cell, nullptr, access);
 
   if (stub->is_constant()) {
     IfBuilder builder(this);
     builder.If<HCompareObjectEqAndBranch>(cell_contents, value);
     builder.Then();
     builder.ElseDeopt(
         Deoptimizer::kUnexpectedCellContentsInConstantGlobalStore);
     builder.End();
@@ skipping 881 matching lines @@
   // megamorphic case is handled as part of the default stub.
   DCHECK(!FLAG_vector_ics);
 
   // Probe the stub cache.
   Add<HTailCallThroughMegamorphicCache>(receiver, name);
 
   // We never continue.
   return graph()->GetConstant0();
 }
 } }  // namespace v8::internal