Strict mode delete.

src/x64/codegen-x64.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7212 matching lines @@
     destination()->Invert();
     LoadCondition(node->expression(), destination(), true);
     // Swap the labels back.
     destination()->Invert();
 
   } else if (op == Token::DELETE) {
     Property* property = node->expression()->AsProperty();
     if (property != NULL) {
       Load(property->obj());
       Load(property->key());
-      Result answer = frame_->InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION, 2);
+      frame_->Push(Smi::FromInt(strict_mode_flag()));
+      Result answer = frame_->InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION, 3);
       frame_->Push(&answer);
       return;
     }
 
     Variable* variable = node->expression()->AsVariableProxy()->AsVariable();
     if (variable != NULL) {
+      ASSERT(strict_mode_flag() == kNonStrictMode);
       Slot* slot = variable->AsSlot();
       if (variable->is_global()) {
         LoadGlobal();
         frame_->Push(variable->name());
+        frame_->Push(Smi::FromInt(kNonStrictMode));
         Result answer = frame_->InvokeBuiltin(Builtins::DELETE,
-                                              CALL_FUNCTION, 2);
+                                              CALL_FUNCTION, 3);
         frame_->Push(&answer);
         return;
 
       } else if (slot != NULL && slot->type() == Slot::LOOKUP) {
         // Call the runtime to delete from the context holding the named
         // variable.  Sync the virtual frame eagerly so we can push the
         // arguments directly into place.
         frame_->SyncRange(0, frame_->element_count() - 1);
         frame_->EmitPush(rsi);
         frame_->EmitPush(variable->name());
@@ skipping 1554 matching lines @@
 }
 
 #endif
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64