Merge up to 8597 to experimental/gc from the bleeding edge.

src/scopes.h

-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2011 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
 //       with the distribution.
@@ skipping 71 matching lines @@
 // allocation binds each unresolved VariableProxy to one Variable and assigns
 // a location. Note that many VariableProxy nodes may refer to the same Java-
 // Script variable.
 
 class Scope: public ZoneObject {
  public:
   // ---------------------------------------------------------------------------
   // Construction
 
   enum Type {
-    EVAL_SCOPE,     // the top-level scope for an 'eval' source
-    FUNCTION_SCOPE,  // the top-level scope for a function
-    GLOBAL_SCOPE    // the top-level scope for a program or a top-level eval
-  };
-
-  enum LocalType {
-    PARAMETER,
-    VAR_OR_CONST
+    EVAL_SCOPE,      // The top-level scope for an eval source.
+    FUNCTION_SCOPE,  // The top-level scope for a function.
+    GLOBAL_SCOPE,    // The top-level scope for a program or a top-level eval.
+    CATCH_SCOPE      // The scope introduced by catch.
   };
 
   Scope(Scope* outer_scope, Type type);
 
-  virtual ~Scope() { }
-
   // Compute top scope and allocate variables. For lazy compilation the top
   // scope only contains the single lazily compiled function, so this
   // doesn't re-allocate variables repeatedly.
   static bool Analyze(CompilationInfo* info);
 
   static Scope* DeserializeScopeChain(CompilationInfo* info,
                                       Scope* innermost_scope);
 
   // The scope name is only used for printing/debugging.
   void SetScopeName(Handle<String> scope_name) { scope_name_ = scope_name; }
 
-  virtual void Initialize(bool inside_with);
-
-  // Called just before leaving a scope.
-  virtual void Leave() {
-    // No cleanup or fixup necessary.
-  }
+  void Initialize(bool inside_with);
 
   // ---------------------------------------------------------------------------
   // Declarations
 
   // Lookup a variable in this scope. Returns the variable or NULL if not found.
-  virtual Variable* LocalLookup(Handle<String> name);
+  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);
+  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 parameter in this scope.  When there are duplicated
+  // parameters the rightmost one 'wins'.  However, the implementation
+  // expects all parameters to be declared and from left to right.
+  void DeclareParameter(Handle<String> name);
+
   // Declare a local variable in this scope. If the variable has been
   // declared before, the previously declared variable is returned.
-  virtual Variable* DeclareLocal(Handle<String> name,
-                                 Variable::Mode mode,
-                                 LocalType type);
+  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 than 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,
-                                       int position = RelocInfo::kNoPosition);
+  VariableProxy* NewUnresolved(Handle<String> name,
+                               bool inside_with,
+                               int position = RelocInfo::kNoPosition);
 
   // Remove a unresolved variable. During parsing, an unresolved variable
   // may have been added optimistically, but then only the variable name
   // was used (typically for labels). If the variable was not declared, the
   // addition introduced a new unresolved variable which may end up being
   // allocated globally as a "ghost" variable. RemoveUnresolved removes
   // such a variable again if it was added; otherwise this is a no-op.
   void RemoveUnresolved(VariableProxy* var);
 
   // Creates a new temporary variable in this scope.  The name is only used
   // for printing and cannot be used to find the variable.  In particular,
   // the only way to get hold of the temporary is by keeping the Variable*
   // around.
-  virtual Variable* NewTemporary(Handle<String> name);
+  Variable* NewTemporary(Handle<String> name);
 
   // Adds the specific declaration node to the list of declarations in
   // this scope. The declarations are processed as part of entering
   // the scope; see codegen.cc:ProcessDeclarations.
   void AddDeclaration(Declaration* declaration);
 
   // ---------------------------------------------------------------------------
   // Illegal redeclaration support.
 
   // Set an expression node that will be executed when the scope is
@@ skipping 24 matching lines @@
     strict_mode_ = FLAG_strict_mode;
   }
 
   // ---------------------------------------------------------------------------
   // Predicates.
 
   // Specific scope types.
   bool is_eval_scope() const { return type_ == EVAL_SCOPE; }
   bool is_function_scope() const { return type_ == FUNCTION_SCOPE; }
   bool is_global_scope() const { return type_ == GLOBAL_SCOPE; }
+  bool is_catch_scope() const { return type_ == CATCH_SCOPE; }
   bool is_strict_mode() const { return strict_mode_; }
   bool is_strict_mode_eval_scope() const {
     return is_eval_scope() && is_strict_mode();
   }
 
   // Information about which scopes calls eval.
   bool calls_eval() const { return scope_calls_eval_; }
   bool outer_scope_calls_eval() const { return outer_scope_calls_eval_; }
   bool outer_scope_calls_non_strict_eval() const {
     return outer_scope_calls_non_strict_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_; }
 
   // The scope immediately surrounding this scope, or NULL.
   Scope* outer_scope() const { return outer_scope_; }
 
   // ---------------------------------------------------------------------------
   // Accessors.
 
-  // A new variable proxy corresponding to the (function) receiver.
-  VariableProxy* receiver() const {
-    VariableProxy* proxy =
-        new VariableProxy(FACTORY->this_symbol(), true, false);
-    proxy->BindTo(receiver_);
-    return proxy;
-  }
+  // The variable corresponding the 'this' value.
+  Variable* receiver() { return receiver_; }
 
   // The variable holding the function literal for named function
   // literals, or NULL.
   // Only valid for function scopes.
   Variable* function() const {
     ASSERT(is_function_scope());
     return function_;
   }
 
   // Parameters. The left-most parameter has index 0.
   // Only valid for function scopes.
   Variable* parameter(int index) const {
     ASSERT(is_function_scope());
     return params_[index];
   }
 
   int num_parameters() const { return params_.length(); }
 
   // The local variable 'arguments' if we need to allocate it; NULL otherwise.
-  // If arguments() exist, arguments_shadow() exists, too.
   Variable* arguments() const { return arguments_; }
 
-  // The '.arguments' shadow variable if we need to allocate it; NULL otherwise.
-  // If arguments_shadow() exist, arguments() exists, too.
-  Variable* arguments_shadow() const { return arguments_shadow_; }
-
   // Declarations list.
   ZoneList<Declaration*>* declarations() { return &decls_; }
 
 
-
   // ---------------------------------------------------------------------------
   // Variable allocation.
 
   // Collect all used locals in this scope.
   template<class Allocator>
   void CollectUsedVariables(List<Variable*, Allocator>* locals);
 
   // Resolve and fill in the allocation information for all variables
   // in this scopes. Must be called *after* all scopes have been
   // processed (parsed) to ensure that unresolved variables can be
@@ skipping 11 matching lines @@
   int num_stack_slots() const { return num_stack_slots_; }
   int num_heap_slots() const { return num_heap_slots_; }
 
   // Make sure this scope and all outer scopes are eagerly compiled.
   void ForceEagerCompilation()  { force_eager_compilation_ = true; }
 
   // Determine if we can use lazy compilation for this scope.
   bool AllowsLazyCompilation() const;
 
   // True if the outer context of this scope is always the global context.
-  virtual bool HasTrivialOuterContext() const;
+  bool HasTrivialOuterContext() const;
 
   // The number of contexts between this and scope; zero if this == scope.
   int ContextChainLength(Scope* scope);
 
+  // Find the first function, global, or eval scope.  This is the scope
+  // where var declarations will be hoisted to in the implementation.
+  Scope* DeclarationScope();
+
   // ---------------------------------------------------------------------------
   // Strict mode support.
   bool IsDeclared(Handle<String> name) {
     // During formal parameter list parsing the scope only contains
     // two variables inserted at initialization: "this" and "arguments".
     // "this" is an invalid parameter name and "arguments" is invalid parameter
     // name in strict mode. Therefore looking up with the map which includes
     // "this" and "arguments" in addition to all formal parameters is safe.
     return variables_.Lookup(name) != NULL;
   }
@@ skipping 37 matching lines @@
   // Unresolved variables referred to from this scope.
   ZoneList<VariableProxy*> unresolved_;
   // Declarations.
   ZoneList<Declaration*> decls_;
   // Convenience variable.
   Variable* receiver_;
   // Function variable, if any; function scopes only.
   Variable* function_;
   // Convenience variable; function scopes only.
   Variable* arguments_;
-  // Convenience variable; function scopes only.
-  Variable* 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
   bool strict_mode_;  // this scope is a strict mode scope
 
   // Computed via PropagateScopeInfo.
   bool outer_scope_calls_eval_;
   bool outer_scope_calls_non_strict_eval_;
   bool inner_scope_calls_eval_;
   bool outer_scope_is_eval_scope_;
   bool force_eager_compilation_;
 
+  // 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_;
 
   // Computed via AllocateVariables; function scopes only.
   int num_stack_slots_;
   int num_heap_slots_;
 
   // Serialized scopes support.
   Handle<SerializedScopeInfo> scope_info_;
-  bool resolved() { return !scope_info_.is_null(); }
+  bool already_resolved() { return already_resolved_; }
 
   // Create a non-local variable with a given name.
   // These variables are looked up dynamically at runtime.
   Variable* NonLocal(Handle<String> name, Variable::Mode mode);
 
   // Variable resolution.
   Variable* LookupRecursive(Handle<String> name,
                             bool inner_lookup,
                             Variable** invalidated_local);
   void ResolveVariable(Scope* global_scope,
@@ skipping 15 matching lines @@
 
   // Variable allocation.
   void AllocateStackSlot(Variable* var);
   void AllocateHeapSlot(Variable* var);
   void AllocateParameterLocals();
   void AllocateNonParameterLocal(Variable* var);
   void AllocateNonParameterLocals();
   void AllocateVariablesRecursively();
 
  private:
+  // Construct a function scope based on the scope info.
   Scope(Scope* inner_scope, Handle<SerializedScopeInfo> scope_info);
 
+  // Construct a catch scope with a binding for the name.
+  Scope(Scope* inner_scope, Handle<String> catch_variable_name);
+
   void AddInnerScope(Scope* inner_scope) {
     if (inner_scope != NULL) {
       inner_scopes_.Add(inner_scope);
       inner_scope->outer_scope_ = this;
     }
   }
 
   void SetDefaults(Type type,
                    Scope* outer_scope,
                    Handle<SerializedScopeInfo> scope_info);
 };
 
-
-// Scope used during pre-parsing.
-class DummyScope : public Scope {
- public:
-  DummyScope()
-      : Scope(GLOBAL_SCOPE),
-        nesting_level_(1),  // Allows us to Leave the initial scope.
-        inside_with_level_(kNotInsideWith) {
-    outer_scope_ = this;
-    scope_inside_with_ = false;
-  }
-
-  virtual void Initialize(bool inside_with) {
-    nesting_level_++;
-    if (inside_with && inside_with_level_ == kNotInsideWith) {
-      inside_with_level_ = nesting_level_;
-    }
-    ASSERT(inside_with_level_ <= nesting_level_);
-  }
-
-  virtual void Leave() {
-    nesting_level_--;
-    ASSERT(nesting_level_ >= 0);
-    if (nesting_level_ < inside_with_level_) {
-      inside_with_level_ = kNotInsideWith;
-    }
-    ASSERT(inside_with_level_ <= nesting_level_);
-  }
-
-  virtual Variable* Lookup(Handle<String> name)  { return NULL; }
-
-  virtual VariableProxy* NewUnresolved(Handle<String> name,
-                                       bool inside_with,
-                                       int position = RelocInfo::kNoPosition) {
-    return NULL;
-  }
-
-  virtual Variable* NewTemporary(Handle<String> name)  { return NULL; }
-
-  virtual bool HasTrivialOuterContext() const {
-    return (nesting_level_ == 0 || inside_with_level_ <= 0);
-  }
-
- private:
-  static const int kNotInsideWith = -1;
-  // Number of surrounding scopes of the current scope.
-  int nesting_level_;
-  // Nesting level of outermost scope that is contained in a with statement,
-  // or kNotInsideWith if there are no with's around the current scope.
-  int inside_with_level_;
-};
-
-
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_