Remove strong mode support from Scope and Variable

src/ast/variables.h

 // Copyright 2011 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_AST_VARIABLES_H_
 #define V8_AST_VARIABLES_H_
 
 #include "src/ast/ast-value-factory.h"
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 // The AST refers to variables via VariableProxies - placeholders for the actual
 // variables. Variables themselves are never directly referred to from the AST,
 // they are maintained by scopes, and referred to from VariableProxies and Slots
 // after binding and variable allocation.
-
-class ClassVariable;
-
 class Variable: public ZoneObject {
  public:
-  enum Kind { NORMAL, FUNCTION, CLASS, THIS, ARGUMENTS };
+  enum Kind { NORMAL, FUNCTION, THIS, ARGUMENTS };
 
   Variable(Scope* scope, const AstRawString* name, VariableMode mode, Kind kind,
            InitializationFlag initialization_flag,
            MaybeAssignedFlag maybe_assigned_flag = kNotAssigned);
 
   virtual ~Variable() {}
 
   // Printing support
   static const char* Mode2String(VariableMode mode);
 
@@ skipping 43 matching lines @@
   bool IsGlobalObjectProperty() const;
   bool IsStaticGlobalObjectProperty() const;
 
   bool is_dynamic() const { return IsDynamicVariableMode(mode_); }
   bool is_const_mode() const { return IsImmutableVariableMode(mode_); }
   bool binding_needs_init() const {
     return initialization_flag_ == kNeedsInitialization;
   }
 
   bool is_function() const { return kind_ == FUNCTION; }
-  bool is_class() const { return kind_ == CLASS; }
   bool is_this() const { return kind_ == THIS; }
   bool is_arguments() const { return kind_ == ARGUMENTS; }
 
   // For script scopes, the "this" binding is provided by a ScriptContext added
   // to the global's ScriptContextTable.  This binding might not statically
   // resolve to a Variable::THIS binding, instead being DYNAMIC_LOCAL.  However
   // any variable named "this" does indeed refer to a Variable::THIS binding;
   // the grammar ensures this to be the case.  So wherever a "this" binding
   // might be provided by the global, use HasThisName instead of is_this().
   bool HasThisName(Isolate* isolate) const {
     return is_this() || *name() == *isolate->factory()->this_string();
   }
 
-  ClassVariable* AsClassVariable() {
-    DCHECK(is_class());
-    return reinterpret_cast<ClassVariable*>(this);
-  }
-
   // True if the variable is named eval and not known to be shadowed.
   bool is_possibly_eval(Isolate* isolate) const {
     return IsVariable(isolate->factory()->eval_string());
   }
 
   Variable* local_if_not_shadowed() const {
     DCHECK(mode_ == DYNAMIC_LOCAL && local_if_not_shadowed_ != NULL);
     return local_if_not_shadowed_;
   }
 
   void set_local_if_not_shadowed(Variable* local) {
     local_if_not_shadowed_ = local;
   }
 
   VariableLocation location() const { return location_; }
   int index() const { return index_; }
   InitializationFlag initialization_flag() const {
     return initialization_flag_;
   }
 
   void AllocateTo(VariableLocation location, int index) {
     location_ = location;
     index_ = index;
   }
 
   void SetFromEval() { is_from_eval_ = true; }
 
   static int CompareIndex(Variable* const* v, Variable* const* w);
 
-  void RecordStrongModeReference(int start_position, int end_position) {
-    // Record the earliest reference to the variable. Used in error messages for
-    // strong mode references to undeclared variables.
-    if (has_strong_mode_reference_ &&
-        strong_mode_reference_start_position_ < start_position)
-      return;
-    has_strong_mode_reference_ = true;
-    strong_mode_reference_start_position_ = start_position;
-    strong_mode_reference_end_position_ = end_position;
-  }
-
-  bool has_strong_mode_reference() const { return has_strong_mode_reference_; }
-  int strong_mode_reference_start_position() const {
-    return strong_mode_reference_start_position_;
-  }
-  int strong_mode_reference_end_position() const {
-    return strong_mode_reference_end_position_;
-  }
   PropertyAttributes DeclarationPropertyAttributes() const {
     int property_attributes = NONE;
     if (IsImmutableVariableMode(mode_)) {
       property_attributes |= READ_ONLY;
     }
     if (is_from_eval_) {
       property_attributes |= EVAL_DECLARED;
     }
     return static_cast<PropertyAttributes>(property_attributes);
   }
 
  private:
   Scope* scope_;
   const AstRawString* name_;
   VariableMode mode_;
   Kind kind_;
   VariableLocation location_;
   int index_;
   int initializer_position_;
-  // Tracks whether the variable is bound to a VariableProxy which is in strong
-  // mode, and if yes, the source location of the reference.
-  bool has_strong_mode_reference_;
-  int strong_mode_reference_start_position_;
-  int strong_mode_reference_end_position_;
 
   // If this field is set, this variable references the stored locally bound
   // variable, but it might be shadowed by variable bindings introduced by
   // sloppy 'eval' calls between the reference scope (inclusive) and the
   // binding scope (exclusive).
   Variable* local_if_not_shadowed_;
 
   // True if this variable is introduced by a sloppy eval
   bool is_from_eval_;
 
   // Usage info.
   bool force_context_allocation_;  // set by variable resolver
   bool is_used_;
   InitializationFlag initialization_flag_;
   MaybeAssignedFlag maybe_assigned_;
 };
-
-class ClassVariable : public Variable {
- public:
-  ClassVariable(Scope* scope, const AstRawString* name, VariableMode mode,
-                InitializationFlag initialization_flag,
-                MaybeAssignedFlag maybe_assigned_flag = kNotAssigned,
-                int declaration_group_start = -1)
-      : Variable(scope, name, mode, Variable::CLASS, initialization_flag,
-                 maybe_assigned_flag),
-        declaration_group_start_(declaration_group_start) {}
-
-  int declaration_group_start() const { return declaration_group_start_; }
-  void set_declaration_group_start(int declaration_group_start) {
-    declaration_group_start_ = declaration_group_start;
-  }
-
- private:
-  // For classes we keep track of consecutive groups of delcarations. They are
-  // needed for strong mode scoping checks. TODO(marja, rossberg): Implement
-  // checks for functions too.
-  int declaration_group_start_;
-};
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_VARIABLES_H_