[runtime] Optimize and unify rest parameters.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 569 matching lines @@
 }
 
 
 void BytecodeGenerator::MakeBytecodeBody() {
   // Build the arguments object if it is used.
   VisitArgumentsObject(scope()->arguments());
 
   // Build rest arguments array if it is used.
   int rest_index;
   Variable* rest_parameter = scope()->rest_parameter(&rest_index);
-  VisitRestArgumentsArray(rest_parameter, rest_index);
+  VisitRestArgumentsArray(rest_parameter);
 
   // Build assignment to {.this_function} variable if it is used.
   VisitThisFunctionVariable(scope()->this_function_var());
 
   // Build assignment to {new.target} variable if it is used.
   VisitNewTargetVariable(scope()->new_target_var());
 
   // TODO(rmcilroy): Emit tracing call if requested to do so.
   if (FLAG_trace) {
     UNIMPLEMENTED();
@@ skipping 1996 matching lines @@
   // Allocate and initialize a new arguments object and assign to the
   // {arguments} variable.
   CreateArgumentsType type =
       is_strict(language_mode()) || !info()->has_simple_parameters()
           ? CreateArgumentsType::kUnmappedArguments
           : CreateArgumentsType::kMappedArguments;
   builder()->CreateArguments(type);
   VisitVariableAssignment(variable, FeedbackVectorSlot::Invalid());
 }
 
-void BytecodeGenerator::VisitRestArgumentsArray(Variable* rest, int index) {
+void BytecodeGenerator::VisitRestArgumentsArray(Variable* rest) {
   if (rest == nullptr) return;
 
-  // Allocate and initialize a new arguments object and assign to the {rest}
+  // Allocate and initialize a new rest parameter and assign to the {rest}
   // variable.
-  builder()->CreateRestArguments(index);
+  builder()->CreateArguments(CreateArgumentsType::kRestParameter);
   DCHECK(rest->IsContextSlot() || rest->IsStackAllocated());
   VisitVariableAssignment(rest, FeedbackVectorSlot::Invalid());
 }
 
 void BytecodeGenerator::VisitThisFunctionVariable(Variable* variable) {
   if (variable == nullptr) return;
 
   // TODO(rmcilroy): Remove once we have tests which exercise this code path.
   UNIMPLEMENTED();
 
@@ skipping 86 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8