Allow variable proxies for the same global variable to share the same...

src/scopes.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 17 matching lines @@
 #ifndef V8_SCOPES_H_
 #define V8_SCOPES_H_
 
 #include "ast.h"
 #include "hashmap.h"
 
 namespace v8 {
 namespace internal {
 
 
-// A hash map to support fast local variable declaration and lookup.
-class LocalsMap: public HashMap {
+// A hash map to support fast variable declaration and lookup.
+class VariableMap: public HashMap {
  public:
-  LocalsMap();
+  VariableMap();
 
   // Dummy constructor.  This constructor doesn't set up the map
   // properly so don't use it unless you have a good reason.
-  explicit LocalsMap(bool gotta_love_static_overloading);
+  explicit VariableMap(bool gotta_love_static_overloading);
 
-  virtual ~LocalsMap();
+  virtual ~VariableMap();
 
-  Variable* Declare(Scope* scope, Handle<String> name, Variable::Mode mode,
-                    bool is_valid_LHS, Variable::Kind kind);
+  Variable* Declare(Scope* scope,
+                    Handle<String> name,
+                    Variable::Mode mode,
+                    bool is_valid_lhs,
+                    Variable::Kind kind);
 
   Variable* Lookup(Handle<String> name);
 };
 
 
 // The dynamic scope part holds hash maps for the variables that will
 // be looked up dynamically from within eval and with scopes. The objects
 // are allocated on-demand from Scope::NonLocal to avoid wasting memory
 // and setup time for scopes that don't need them.
 class DynamicScopePart : public ZoneObject {
  public:
-  LocalsMap* GetMap(Variable::Mode mode) {
+  VariableMap* GetMap(Variable::Mode mode) {
     int index = mode - Variable::DYNAMIC;
     ASSERT(index >= 0 && index < 3);
     return &maps_[index];
   }
 
  private:
-  LocalsMap maps_[3];
+  VariableMap maps_[3];
 };
 
 
 // Global invariants after AST construction: Each reference (i.e. identifier)
 // to a JavaScript variable (including global properties) is represented by a
 // VariableProxy node. Immediately after AST construction and before variable
 // allocation, most VariableProxy nodes are "unresolved", i.e. not bound to a
 // corresponding variable (though some are bound during parse time). Variable
 // allocation binds each unresolved VariableProxy to one Variable and assigns
 // a location. Note that many VariableProxy nodes may refer to the same Java-
@@ skipping 18 matching lines @@
   // The scope name is only used for printing/debugging.
   void SetScopeName(Handle<String> scope_name)  { scope_name_ = scope_name; }
 
   void Initialize(bool inside_with);
 
 
   // ---------------------------------------------------------------------------
   // Declarations
 
   // Lookup a variable in this scope. Returns the variable or NULL if not found.
-  virtual Variable* LookupLocal(Handle<String> name);
+  virtual Variable* LocalLookup(Handle<String> name);
 
   // Lookup a variable in this scope or outer scopes.
   // Returns the variable or NULL if not found.
   virtual Variable* Lookup(Handle<String> name);
 
   // Declare the function variable for a function literal. This variable
   // is in an intermediate scope between this function scope and the the
   // outer scope. Only possible for function scopes; at most one variable.
   Variable* DeclareFunctionVar(Handle<String> name);
 
-  // Declare a variable in this scope. If the variable has been
+  // Declare a local variable in this scope. If the variable has been
   // declared before, the previously declared variable is returned.
-  virtual Variable* Declare(Handle<String> name, Variable::Mode mode);
+  virtual Variable* DeclareLocal(Handle<String> name, Variable::Mode mode);
+
+  // Declare an implicit global variable in this scope which must be a
+  // global scope.  The variable was introduced (possibly from an inner
+  // scope) by a reference to an unresolved variable with no intervening
+  // with statements or eval calls.
+  Variable* DeclareGlobal(Handle<String> name);
 
   // Add a parameter to the parameter list. The parameter must have been
   // declared via Declare. The same parameter may occur more then once in
   // the parameter list; they must be added in source order, from left to
   // right.
   void AddParameter(Variable* var);
 
   // Create a new unresolved variable.
   virtual VariableProxy* NewUnresolved(Handle<String> name, bool inside_with);
 
@@ skipping 149 matching lines @@
   Scope* outer_scope_;  // the immediately enclosing outer scope, or NULL
   ZoneList<Scope*> inner_scopes_;  // the immediately enclosed inner scopes
 
   // The scope type.
   Type type_;
 
   // Debugging support.
   Handle<String> scope_name_;
 
   // The variables declared in this scope:
-  // all user-declared variables (incl. parameters)
-  LocalsMap locals_;
-  // compiler-allocated (user-invisible) temporaries
+  //
+  // All user-declared variables (incl. parameters).  For global scopes
+  // variables may be implicitly 'declared' by being used (possibly in
+  // an inner scope) with no intervening with statements or eval calls.
+  VariableMap variables_;
+  // Compiler-allocated (user-invisible) temporaries.
   ZoneList<Variable*> temps_;
-  // parameter list in source order
+  // Parameter list in source order.
   ZoneList<Variable*> params_;
-  // variables that must be looked up dynamically
+  // Variables that must be looked up dynamically.
   DynamicScopePart* dynamics_;
-  // unresolved variables referred to from this scope
+  // Unresolved variables referred to from this scope.
   ZoneList<VariableProxy*> unresolved_;
-  // declarations
+  // Declarations.
   ZoneList<Declaration*> decls_;
-  // convenience variable
+  // Convenience variable.
   VariableProxy* receiver_;
-  // function variable, if any; function scopes only
+  // Function variable, if any; function scopes only.
   Variable* function_;
-  // convenience variable; function scopes only
+  // Convenience variable; function scopes only.
   VariableProxy* arguments_;
-  // convenience variable; function scopes only
+  // Convenience variable; function scopes only.
   VariableProxy* arguments_shadow_;
 
   // Illegal redeclaration.
   Expression* illegal_redecl_;
 
   // Scope-specific information.
   bool scope_inside_with_;  // this scope is inside a 'with' of some outer scope
   bool scope_contains_with_;  // this scope contains a 'with' statement
   bool scope_calls_eval_;  // this scope contains an 'eval' call
 
@@ skipping 54 matching lines @@
   virtual VariableProxy* NewUnresolved(Handle<String> name, bool inside_with) {
     return NULL;
   }
   virtual VariableProxy* NewTemporary(Handle<String> name)  { return NULL; }
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_