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

src/scopes.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_SCOPES_H_
 #define V8_SCOPES_H_
 
 #include "src/ast.h"
 #include "src/zone.h"
 
@@ skipping 193 matching lines @@
 
   // ---------------------------------------------------------------------------
   // Scope-specific info.
 
   // Inform the scope that the corresponding code contains a with statement.
   void RecordWithStatement() { scope_contains_with_ = true; }
 
   // 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; }
 
   // Position in the source where this scope begins and ends.
   //
   // * For the scope of a with statement
   //     with (obj) stmt
   //   start position: start position of first token of 'stmt'
   //   end position: end position of last token of 'stmt'
   // * For the scope of a block
@@ skipping 56 matching lines @@
   }
   bool outer_scope_calls_sloppy_eval() const {
     return outer_scope_calls_sloppy_eval_;
   }
 
   // Is this scope inside a with statement.
   bool inside_with() const { return scope_inside_with_; }
   // 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.
 
   // The type of this scope.
   ScopeType scope_type() const { return scope_type_; }
 
   // The language mode of this scope.
   StrictMode strict_mode() const { return strict_mode_; }
 
   // The variable corresponding the 'this' value.
@@ skipping 156 matching lines @@
 
   // Scope-specific information computed during parsing.
   //
   // This scope is inside a 'with' of some outer scope.
   bool scope_inside_with_;
   // This scope contains a 'with' statement.
   bool scope_contains_with_;
   // 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.
   int start_position_;
   int end_position_;
 
   // 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_;
 
   // True if it doesn't need scope resolution (e.g., if the scope was
   // constructed based on a serialized scope info or a catch context).
   bool already_resolved_;
 
   // Computed as variables are declared.
   int num_var_or_const_;
 
@@ skipping 126 matching lines @@
                    Scope* outer_scope,
                    Handle<ScopeInfo> scope_info);
 
   AstValueFactory* ast_value_factory_;
   Zone* zone_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_