Support for global var shortcuts in script contexts.

src/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_VARIABLES_H_
 #define V8_VARIABLES_H_
 
 #include "src/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 Location {
-    // Before and during variable allocation, a variable whose location is
-    // not yet determined.  After allocation, a variable looked up as a
-    // property on the global object (and possibly absent).  name() is the
-    // variable name, index() is invalid.
-    UNALLOCATED,
-
-    // A slot in the parameter section on the stack.  index() is the
-    // parameter index, counting left-to-right.  The receiver is index -1;
-    // the first parameter is index 0.
-    PARAMETER,
-
-    // A slot in the local section on the stack.  index() is the variable
-    // index in the stack frame, starting at 0.
-    LOCAL,
-
-    // An indexed slot in a heap context.  index() is the variable index in
-    // the context object on the heap, starting at 0.  scope() is the
-    // corresponding scope.
-    CONTEXT,
-
-    // A named slot in a heap context.  name() is the variable name in the
-    // context object on the heap, with lookup starting at the current
-    // context.  index() is invalid.
-    LOOKUP
-  };
-
   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);
 
   // The source code for an eval() call may refer to a variable that is
@@ skipping 17 matching lines @@
   MaybeAssignedFlag maybe_assigned() const { return maybe_assigned_; }
   void set_maybe_assigned() { maybe_assigned_ = kMaybeAssigned; }
 
   int initializer_position() { return initializer_position_; }
   void set_initializer_position(int pos) { initializer_position_ = pos; }
 
   bool IsVariable(Handle<String> n) const {
     return !is_this() && name().is_identical_to(n);
   }
 
-  bool IsUnallocated() const { return location_ == UNALLOCATED; }
-  bool IsParameter() const { return location_ == PARAMETER; }
-  bool IsStackLocal() const { return location_ == LOCAL; }
+  bool IsUnallocated() const {
+    return location_ == VariableLocation::UNALLOCATED;
+  }
+  bool IsParameter() const { return location_ == VariableLocation::PARAMETER; }
+  bool IsStackLocal() const { return location_ == VariableLocation::LOCAL; }
   bool IsStackAllocated() const { return IsParameter() || IsStackLocal(); }
-  bool IsContextSlot() const { return location_ == CONTEXT; }
-  bool IsLookupSlot() const { return location_ == LOOKUP; }
+  bool IsContextSlot() const { return location_ == VariableLocation::CONTEXT; }
+  bool IsGlobalSlot() const { return location_ == VariableLocation::GLOBAL; }
+  bool IsUnallocatedOrGlobalSlot() const {
+    return IsUnallocated() || IsGlobalSlot();
+  }
+  bool IsLookupSlot() const { return location_ == VariableLocation::LOOKUP; }
   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; }
@@ skipping 21 matching lines @@
 
   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;
   }
 
-  Location location() const { return location_; }
+  VariableLocation location() const { return location_; }
   int index() const { return index_; }
   InitializationFlag initialization_flag() const {
     return initialization_flag_;
   }
 
-  void AllocateTo(Location location, int index) {
+  void AllocateTo(VariableLocation location, int index) {
     location_ = location;
     index_ = index;
   }
 
   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_ &&
@@ skipping 10 matching lines @@
   }
   int strong_mode_reference_end_position() const {
     return strong_mode_reference_end_position_;
   }
 
  private:
   Scope* scope_;
   const AstRawString* name_;
   VariableMode mode_;
   Kind kind_;
-  Location location_;
+  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
@@ skipping 25 matching lines @@
 
  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 v8::internal
 
 #endif  // V8_VARIABLES_H_