[turbofan] escape analysis supports arguments object and rest elements

src/compiler/js-call-reducer.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/compiler/js-call-reducer.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/js-graph.h"
@@ skipping 118 matching lines @@
     if (type == CreateArgumentsType::kMappedArguments) {
       // Mapped arguments (sloppy mode) cannot be handled if they are aliased.
       if (formal_parameter_count != 0) return NoChange();
     } else if (type == CreateArgumentsType::kRestParameter) {
       start_index = formal_parameter_count;
     }
     // Check if are applying to inlined arguments or to the arguments of
     // the outermost function.
     Node* outer_state = frame_state->InputAt(kFrameStateOuterStateInput);
     if (outer_state->opcode() != IrOpcode::kFrameState) {
-      // TODO(jarin,bmeurer): Support the NewUnmappedArgumentsElement and
-      // NewRestParameterElements in the EscapeAnalysis and Deoptimizer
-      // instead, then we don't need this hack.
-      // Only works with zero formal parameters because of lacking deoptimizer
-      // support.
-      if (type != CreateArgumentsType::kRestParameter &&
-          formal_parameter_count == 0) {
-        // There are no other uses of the {arg_array} except in StateValues,
-        // so we just replace {arg_array} with a marker for the Deoptimizer
-        // that this refers to the arguments object.
-        Node* arguments = graph()->NewNode(common()->ArgumentsObjectState());
-        ReplaceWithValue(arg_array, arguments);
-      }
-
       // Reduce {node} to a JSCallForwardVarargs operation, which just
       // re-pushes the incoming arguments and calls the {target}.
       node->RemoveInput(0);  // Function.prototype.apply
       node->RemoveInput(2);  // arguments
       NodeProperties::ChangeOp(node, javascript()->CallForwardVarargs(
                                          start_index, p.tail_call_mode()));
       return Changed(node);
     }
     // Get to the actual frame state from which to extract the arguments;
     // we can only optimize this in case the {node} was already inlined into
@@ skipping 664 matching lines @@
   return jsgraph()->javascript();
 }
 
 SimplifiedOperatorBuilder* JSCallReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8