X87: Partial revert of rest parameter desugaring.

src/full-codegen/x87/full-codegen-x87.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_X87
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 233 matching lines @@
     SetVar(this_function_var, edi, ebx, ecx);
   }
 
   // Possibly set up a local binding to the new target value.
   Variable* new_target_var = scope()->new_target_var();
   if (new_target_var != nullptr) {
     Comment cmnt(masm_, "[ new.target");
     SetVar(new_target_var, edx, ebx, ecx);
   }
 
+  // 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;
+
+    __ lea(edx, Operand(ebp, StandardFrameConstants::kCallerSPOffset + offset));
+    __ push(edx);
+    __ push(Immediate(Smi::FromInt(num_parameters)));
+    __ push(Immediate(Smi::FromInt(rest_index)));
+    __ push(Immediate(Smi::FromInt(language_mode())));
+    function_in_register = false;
+
+    RestParamAccessStub stub(isolate());
+    __ CallStub(&stub);
+    SetVar(rest_param, eax, ebx, edx);
+  }
+
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Function uses arguments object.
     Comment cmnt(masm_, "[ Allocate arguments object");
     DCHECK(edi.is(ArgumentsAccessNewDescriptor::function()));
     if (!function_in_register) {
       __ mov(edi, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
     }
     // Receiver is just before the parameters on the caller's stack.
     int num_parameters = info->scope()->num_parameters();
@@ skipping 4489 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87