Parser: Delay internalizing strings and values.

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"
 
 namespace v8 {
 namespace internal {
 
 class CompilationInfo;
 
 
 // A hash map to support fast variable declaration and lookup.
 class VariableMap: public ZoneHashMap {
  public:
   explicit VariableMap(Zone* zone);
 
   virtual ~VariableMap();
 
   Variable* Declare(Scope* scope,
-                    Handle<String> name,
+                    const AstString* name,
                     VariableMode mode,
                     bool is_valid_lhs,
                     Variable::Kind kind,
                     InitializationFlag initialization_flag,
                     Interface* interface = Interface::NewValue());
 
-  Variable* Lookup(Handle<String> name);
+  Variable* Lookup(const AstString* name);
 
   Zone* zone() const { return zone_; }
 
  private:
   Zone* zone_;
 };
 
 
 // The dynamic scope part holds hash maps for the variables that will
 // be looked up dynamically from within eval and with scopes. The objects
@@ skipping 24 matching lines @@
 // 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-
 // Script variable.
 
 class Scope: public ZoneObject {
  public:
   // ---------------------------------------------------------------------------
   // Construction
 
-  Scope(Scope* outer_scope, ScopeType scope_type, Zone* zone);
+  Scope(Scope* outer_scope, ScopeType scope_type,
+        AstValueFactory* value_factory, Zone* zone);
 
   // 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(Context* context, Scope* global_scope,
                                       Zone* zone);
 
   // The scope name is only used for printing/debugging.
-  void SetScopeName(Handle<String> scope_name) { scope_name_ = scope_name; }
+  void SetScopeName(const AstString* scope_name) { scope_name_ = scope_name; }
 
   void Initialize();
 
   // Checks if the block scope is redundant, i.e. it does not contain any
   // block scoped declarations. In that case it is removed from the scope
   // tree and its children are reparented.
   Scope* FinalizeBlockScope();
 
   Zone* zone() const { return zone_; }
 
   // ---------------------------------------------------------------------------
   // Declarations
 
   // Lookup a variable in this scope. Returns the variable or NULL if not found.
-  Variable* LookupLocal(Handle<String> name);
+  Variable* LookupLocal(const AstString* name);
 
   // This lookup corresponds to a lookup in the "intermediate" scope sitting
   // between this scope and the outer scope. (ECMA-262, 3rd., requires that
   // the name of named function literal is kept in an intermediate scope
   // in between this scope and the next outer scope.)
-  Variable* LookupFunctionVar(Handle<String> name,
+  Variable* LookupFunctionVar(const AstString* name,
                               AstNodeFactory<AstNullVisitor>* factory);
 
   // Lookup a variable in this scope or outer scopes.
   // Returns the variable or NULL if not found.
-  Variable* Lookup(Handle<String> name);
+  Variable* Lookup(const AstString* 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.
   void DeclareFunctionVar(VariableDeclaration* declaration) {
     ASSERT(is_function_scope());
     function_ = declaration;
   }
 
   // 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, VariableMode mode);
+  void DeclareParameter(const AstString* name, VariableMode mode);
 
   // Declare a local variable in this scope. If the variable has been
   // declared before, the previously declared variable is returned.
-  Variable* DeclareLocal(Handle<String> name,
+  Variable* DeclareLocal(const AstString* name,
                          VariableMode mode,
                          InitializationFlag init_flag,
                          Interface* interface = Interface::NewValue());
 
   // 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* DeclareDynamicGlobal(Handle<String> name);
+  Variable* DeclareDynamicGlobal(const AstString* name);
 
   // Create a new unresolved variable.
   template<class Visitor>
   VariableProxy* NewUnresolved(AstNodeFactory<Visitor>* factory,
-                               Handle<String> name,
+                               const AstString* name,
                                Interface* interface = Interface::NewValue(),
                                int position = RelocInfo::kNoPosition) {
     // Note that we must not share the unresolved variables with
     // the same name because they may be removed selectively via
     // RemoveUnresolved().
     ASSERT(!already_resolved());
     VariableProxy* proxy =
         factory->NewVariableProxy(name, false, interface, position);
     unresolved_.Add(proxy, zone_);
     return proxy;
   }
 
   // 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 internal 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.
-  Variable* NewInternal(Handle<String> name);
+  Variable* NewInternal(const AstString* name);
 
   // 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.  The name should not clash with a legitimate variable names.
-  Variable* NewTemporary(Handle<String> name);
+  Variable* NewTemporary(const AstString* 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 196 matching lines @@
 
   // Get the chain of nested scopes within this scope for the source statement
   // position. The scopes will be added to the list from the outermost scope to
   // the innermost scope. Only nested block, catch or with scopes are tracked
   // and will be returned, but no inner function scopes.
   void GetNestedScopeChain(List<Handle<ScopeInfo> >* chain,
                            int statement_position);
 
   // ---------------------------------------------------------------------------
   // Strict mode support.
-  bool IsDeclared(Handle<String> name) {
+  bool IsDeclared(const AstString* 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;
   }
 
   // ---------------------------------------------------------------------------
   // Debugging.
@@ skipping 10 matching lines @@
   Isolate* const isolate_;
 
   // Scope tree.
   Scope* outer_scope_;  // the immediately enclosing outer scope, or NULL
   ZoneList<Scope*> inner_scopes_;  // the immediately enclosed inner scopes
 
   // The scope type.
   ScopeType scope_type_;
 
   // Debugging support.
-  Handle<String> scope_name_;
+  const AstString* scope_name_;
 
   // The variables declared in this scope:
   //
   // 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) internals.
   ZoneList<Variable*> internals_;
   // Compiler-allocated (user-invisible) temporaries.
@@ skipping 55 matching lines @@
 
   // For module scopes, the host scope's internal variable binding this module.
   Variable* module_var_;
 
   // Serialized scope info support.
   Handle<ScopeInfo> scope_info_;
   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, VariableMode mode);
+  Variable* NonLocal(const AstString* name, VariableMode mode);
 
   // Variable resolution.
   // Possible results of a recursive variable lookup telling if and how a
   // variable is bound. These are returned in the output parameter *binding_kind
   // of the LookupRecursive function.
   enum BindingKind {
     // The variable reference could be statically resolved to a variable binding
     // which is returned. There is no 'with' statement between the reference and
     // the binding and no scope between the reference scope (inclusive) and
     // binding scope (exclusive) makes a sloppy 'eval' call.
@@ skipping 30 matching lines @@
     //   The variable potentially references a property of the 'with' object.
     // * The code is being executed as part of a call to 'eval' and the calling
     //   context chain contains either a variable binding for the name or it
     //   contains a 'with' context.
     DYNAMIC_LOOKUP
   };
 
   // Lookup a variable reference given by name recursively starting with this
   // scope. If the code is executed because of a call to 'eval', the context
   // parameter should be set to the calling context of 'eval'.
-  Variable* LookupRecursive(Handle<String> name,
+  Variable* LookupRecursive(const AstString* name,
                             BindingKind* binding_kind,
                             AstNodeFactory<AstNullVisitor>* factory);
   MUST_USE_RESULT
   bool ResolveVariable(CompilationInfo* info,
                        VariableProxy* proxy,
                        AstNodeFactory<AstNullVisitor>* factory);
   MUST_USE_RESULT
   bool ResolveVariablesRecursively(CompilationInfo* info,
                                    AstNodeFactory<AstNullVisitor>* factory);
 
@@ skipping 23 matching lines @@
   // In the case of code compiled and run using 'eval', the context
   // parameter is the context in which eval was called.  In all other
   // cases the context parameter is an empty handle.
   MUST_USE_RESULT
   bool AllocateVariables(CompilationInfo* info,
                          AstNodeFactory<AstNullVisitor>* factory);
 
  private:
   // Construct a scope based on the scope info.
   Scope(Scope* inner_scope, ScopeType type, Handle<ScopeInfo> scope_info,
-        Zone* zone);
+        AstValueFactory* value_factory, Zone* zone);
 
   // Construct a catch scope with a binding for the name.
-  Scope(Scope* inner_scope, Handle<String> catch_variable_name, Zone* zone);
+  Scope(Scope* inner_scope,
+        const AstString* catch_variable_name,
+        AstValueFactory* value_factory, Zone* zone);
 
   void AddInnerScope(Scope* inner_scope) {
     if (inner_scope != NULL) {
       inner_scopes_.Add(inner_scope, zone_);
       inner_scope->outer_scope_ = this;
     }
   }
 
   void SetDefaults(ScopeType type,
                    Scope* outer_scope,
                    Handle<ScopeInfo> scope_info);
 
+  AstValueFactory* ast_value_factory_;
   Zone* zone_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_