Track usage of "this" and "arguments" in Scope

src/scopes.h

Index: src/scopes.h
diff --git a/src/scopes.h b/src/scopes.h
index f5903aa02a03aeb1a222eaa9a2dfb026fc38acc4..269fac76bca2891732c63d7235781a6eab114b23 100644
--- a/src/scopes.h
+++ b/src/scopes.h
@@ -211,6 +211,12 @@ class Scope: public ZoneObject {
   // Inform the scope that the corresponding code contains an eval call.
   void RecordEvalCall() { if (!is_global_scope()) scope_calls_eval_ = true; }
 
+  // Inform the scope that the corresponding code uses "this".
+  void RecordThisUsage() { scope_uses_this_ = true; }
+
+  // Inform the scope that the corresponding code uses "arguments".
+  void RecordArgumentsUsage() { scope_uses_arguments_ = true; }
+
   // Set the strict mode flag (unless disabled by a global flag).
   void SetStrictMode(StrictMode strict_mode) { strict_mode_ = strict_mode; }
 
@@ -287,6 +293,15 @@ class Scope: public ZoneObject {
   // Does this scope contain a with statement.
   bool contains_with() const { return scope_contains_with_; }
 
+  // Does this scope access "this".
+  bool uses_this() const { return scope_uses_this_; }
+  // Does any inner scope access "this".
+  bool inner_uses_this() const { return inner_scope_uses_this_; }
+  // Does this scope access "arguments".
+  bool uses_arguments() const { return scope_uses_arguments_; }
+  // Does any inner scope access "arguments".
+  bool inner_uses_arguments() const { return inner_scope_uses_arguments_; }
+
   // ---------------------------------------------------------------------------
   // Accessors.
 
@@ -463,6 +478,10 @@ class Scope: public ZoneObject {
   // This scope or a nested catch scope or with scope contain an 'eval' call. At
   // the 'eval' call site this scope is the declaration scope.
   bool scope_calls_eval_;
+  // This scope uses "this".
+  bool scope_uses_this_;
+  // This scope uses "arguments".
+  bool scope_uses_arguments_;
   // The strict mode of this scope.
   StrictMode strict_mode_;
   // Source positions.
@@ -472,6 +491,8 @@ class Scope: public ZoneObject {
   // Computed via PropagateScopeInfo.
   bool outer_scope_calls_sloppy_eval_;
   bool inner_scope_calls_eval_;
+  bool inner_scope_uses_this_;
+  bool inner_scope_uses_arguments_;
   bool force_eager_compilation_;
   bool force_context_allocation_;