[es6] re-implement rest parameters via desugaring

src/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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 255 matching lines @@
     __ jmp(&done);
 
     // Non-construct frame
     __ bind(&non_construct_frame);
     __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
 
     __ bind(&done);
     SetVar(new_target_var, rax, rbx, rdx);
   }
 
-  // Possibly allocate RestParameters
-  int rest_index;
-  Variable* rest_param = scope()->rest_parameter(&rest_index);
-  if (rest_param) {
-    Comment cmnt(masm_, "[ Allocate rest parameter array");
-
-    int num_parameters = info->scope()->num_parameters();
-    int offset = num_parameters * kPointerSize;
-
-    __ leap(rdx,
-            Operand(rbp, StandardFrameConstants::kCallerSPOffset + offset));
-    __ Push(rdx);
-    __ Push(Smi::FromInt(num_parameters));
-    __ Push(Smi::FromInt(rest_index));
-    __ Push(Smi::FromInt(language_mode()));
-
-    RestParamAccessStub stub(isolate());
-    __ CallStub(&stub);
-
-    SetVar(rest_param, rax, rbx, rdx);
-  }
-
   // Possibly allocate an arguments object.
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Arguments object must be allocated after the context object, in
     // case the "arguments" or ".arguments" variables are in the context.
     Comment cmnt(masm_, "[ Allocate arguments object");
     if (function_in_register) {
       __ Push(rdi);
     } else {
       __ Push(Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
@@ skipping 5166 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64