Pass undefined to JS builtins when called with implicit receiver.

src/x64/full-codegen-x64.cc

 // Copyright 2011 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 113 matching lines @@
   SetFunctionPosition(function());
   Comment cmnt(masm_, "[ function compiled by full code generator");
 
 #ifdef DEBUG
   if (strlen(FLAG_stop_at) > 0 &&
       info->function()->name()->IsEqualTo(CStrVector(FLAG_stop_at))) {
     __ int3();
   }
 #endif
 
-  // Strict mode functions need to replace the receiver with undefined
-  // when called as functions (without an explicit receiver
-  // object). rcx is zero for method calls and non-zero for function
-  // calls.
-  if (info->is_strict_mode()) {
+  // Strict mode functions and builtins need to replace the receiver
+  // with undefined when called as functions (without an explicit
+  // receiver object). rcx is zero for method calls and non-zero for
+  // function calls.
+  if (info->is_strict_mode() || info->is_native()) {
     Label ok;
     __ testq(rcx, rcx);
     __ j(zero, &ok, Label::kNear);
     // +1 for return address.
     int receiver_offset = (scope()->num_parameters() + 1) * kPointerSize;
     __ LoadRoot(kScratchRegister, Heap::kUndefinedValueRootIndex);
     __ movq(Operand(rsp, receiver_offset), kScratchRegister);
     __ bind(&ok);
   }
 
@@ skipping 4160 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64