Remove the rest_parameter(int*) variant, use rest_parameter() instead.

src/full-codegen/x64/full-codegen-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/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 226 matching lines @@
   }
 
   // Possibly set up a local binding to the new target value.
   Variable* new_target_var = info->scope()->new_target_var();
   if (new_target_var != nullptr) {
     Comment cmnt(masm_, "[ new.target");
     SetVar(new_target_var, rdx, rbx, rcx);
   }
 
   // Possibly allocate RestParameters
-  int rest_index;
-  Variable* rest_param = info->scope()->rest_parameter(&rest_index);
-  if (rest_param) {
+  Variable* rest_param = info->scope()->rest_parameter();
+  if (rest_param != nullptr) {
     Comment cmnt(masm_, "[ Allocate rest parameter array");
     if (!function_in_register) {
       __ movp(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
     }
     FastNewRestParameterStub stub(isolate());
     __ CallStub(&stub);
     function_in_register = false;
     SetVar(rest_param, rax, rbx, rdx);
   }
 
@@ skipping 3376 matching lines @@
   DCHECK_EQ(
       isolate->builtins()->OnStackReplacement()->entry(),
       Assembler::target_address_at(call_target_address, unoptimized_code));
   return ON_STACK_REPLACEMENT;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64