Remove ARGUMENTS_VARIABLE and fix crankshaft to properly detect the arguments object and keep it al…

src/crankshaft/hydrogen.h

 // 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.
 
 #ifndef V8_CRANKSHAFT_HYDROGEN_H_
 #define V8_CRANKSHAFT_HYDROGEN_H_
 
 #include "src/accessors.h"
 #include "src/allocation.h"
 #include "src/ast/ast-type-bounds.h"
@@ skipping 2282 matching lines @@
                             BailoutId continue_id, HBasicBlock* exit_block,
                             HBasicBlock* continue_block);
 
   HValue* Top() const { return environment()->Top(); }
   void Drop(int n) { environment()->Drop(n); }
   void Bind(Variable* var, HValue* value) { environment()->Bind(var, value); }
   bool IsEligibleForEnvironmentLivenessAnalysis(Variable* var,
                                                 int index,
                                                 HEnvironment* env) {
     if (!FLAG_analyze_environment_liveness) return false;
-    // |this| and |arguments| are always live; zapping parameters isn't
-    // safe because function.arguments can inspect them at any time.
-    return !var->is_this() &&
-           !var->is_arguments() &&
-           env->is_local_index(index);
+    // Zapping parameters isn't safe because function.arguments can inspect them
+    // at any time.
+    return env->is_local_index(index);
   }
   void BindIfLive(Variable* var, HValue* value) {
     HEnvironment* env = environment();
     int index = env->IndexFor(var);
     env->Bind(index, value);
     if (IsEligibleForEnvironmentLivenessAnalysis(var, index, env)) {
       HEnvironmentMarker* bind =
           Add<HEnvironmentMarker>(HEnvironmentMarker::BIND, index);
       USE(bind);
 #ifdef DEBUG
@@ skipping 717 matching lines @@
   }
 
  private:
   HOptimizedGraphBuilder* builder_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_HYDROGEN_H_