Remove unused 'receiver' field from generators

src/x64/builtins-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 483 matching lines @@
     __ CallRuntime(Runtime::kDebugPrepareStepInIfStepping);
     __ Pop(rdx);
     __ Pop(rbx);
     __ movp(rdi, FieldOperand(rbx, JSGeneratorObject::kFunctionOffset));
   }
   __ bind(&skip_flooding);
 
   // Pop return address.
   __ PopReturnAddressTo(rax);
 
-  // Push receiver.
-  __ Push(FieldOperand(rbx, JSGeneratorObject::kReceiverOffset));
+  // Push hole for the never-used receiver, similarly to arguments below.
+  __ PushRoot(Heap::kTheHoleValueRootIndex);
 
   // ----------- S t a t e -------------
   //  -- rax    : return address
   //  -- rbx    : the JSGeneratorObject to resume
   //  -- rdx    : the resume mode (tagged)
   //  -- rdi    : generator function
   //  -- rsi    : generator context
   //  -- rsp[0] : generator receiver
   // -----------------------------------
 
@@ skipping 2439 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64