Assign bailout and type feedback IDs in a post-pass

src/ast.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_AST_H_
 #define V8_AST_H_
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
@@ skipping 181 matching lines @@
  private:
   Flags flags_;
   int node_count_;
   int feedback_slots_;
   int ic_feedback_slots_;
 };
 
 
 class AstNode: public ZoneObject {
  public:
-  // For generating IDs for AstNodes.
-  class IdGen {
-   public:
-    IdGen() : id_(BailoutId::FirstUsable().ToInt()) {}
-
-    int ReserveIdRange(int n) {
-      int tmp = id_;
-      id_ += n;
-      return tmp;
-    }
-
-   private:
-    int id_;
-
-    DISALLOW_COPY_AND_ASSIGN(IdGen);
-  };
-
 #define DECLARE_TYPE_ENUM(type) k##type,
   enum NodeType {
     AST_NODE_LIST(DECLARE_TYPE_ENUM)
     kInvalid = -1
   };
 #undef DECLARE_TYPE_ENUM
 
   void* operator new(size_t size, Zone* zone) {
     return zone->New(static_cast<int>(size));
   }
@@ skipping 169 matching lines @@
   }
   virtual IcCheckType GetKeyType() {
     UNREACHABLE();
     return ELEMENT;
   }
 
   // TODO(rossberg): this should move to its own AST node eventually.
   virtual void RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle);
   byte to_boolean_types() const { return to_boolean_types_; }
 
-  BailoutId id() const { return BailoutId(base_id() + 0); }
-  TypeFeedbackId test_id() const { return TypeFeedbackId(base_id() + 1); }
+  void set_base_id(int id) { base_id_ = id; }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId id() const { return BailoutId(local_id(0)); }
+  TypeFeedbackId test_id() const { return TypeFeedbackId(local_id(1)); }
 
  protected:
-  Expression(Zone* zone, int pos, int num_ids_needed_by_subclass, IdGen* id_gen)
+  Expression(Zone* zone, int pos)
       : AstNode(pos),
-        base_id_(
-            id_gen->ReserveIdRange(num_ids_needed_by_subclass + num_ids())),
+        base_id_(BailoutId::None().ToInt()),
         bounds_(Bounds::Unbounded(zone)),
         is_parenthesized_(false),
         is_multi_parenthesized_(false) {}
+  static int parent_num_ids() { return 0; }
   void set_to_boolean_types(byte types) { to_boolean_types_ = types; }
 
-  static int num_ids() { return 2; }
-  int base_id() const { return base_id_; }
+  int base_id() const {
+    DCHECK(!BailoutId(base_id_).IsNone());
+    return base_id_;
+  }
 
  private:
-  const int base_id_;
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
+  int base_id_;
   Bounds bounds_;
   byte to_boolean_types_;
   bool is_parenthesized_ : 1;
   bool is_multi_parenthesized_ : 1;
 };
 
 
 class BreakableStatement : public Statement {
  public:
   enum BreakableType {
@@ skipping 11 matching lines @@
   }
 
   // Code generation
   Label* break_target() { return &break_target_; }
 
   // Testers.
   bool is_target_for_anonymous() const {
     return breakable_type_ == TARGET_FOR_ANONYMOUS;
   }
 
-  BailoutId EntryId() const { return BailoutId(base_id() + 0); }
-  BailoutId ExitId() const { return BailoutId(base_id() + 1); }
+  void set_base_id(int id) { base_id_ = id; }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId EntryId() const { return BailoutId(local_id(0)); }
+  BailoutId ExitId() const { return BailoutId(local_id(1)); }
 
  protected:
   BreakableStatement(Zone* zone, ZoneList<const AstRawString*>* labels,
-                     BreakableType breakable_type, int position,
-                     int num_ids_needed_by_subclass, IdGen* id_gen)
+                     BreakableType breakable_type, int position)
       : Statement(zone, position),
         labels_(labels),
         breakable_type_(breakable_type),
-        base_id_(
-            id_gen->ReserveIdRange(num_ids_needed_by_subclass + num_ids())) {
+        base_id_(BailoutId::None().ToInt()) {
     DCHECK(labels == NULL || labels->length() > 0);
   }
+  static int parent_num_ids() { return 0; }
 
-  static int num_ids() { return 2; }
-  int base_id() const { return base_id_; }
+  int base_id() const {
+    DCHECK(!BailoutId(base_id_).IsNone());
+    return base_id_;
+  }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   ZoneList<const AstRawString*>* labels_;
   BreakableType breakable_type_;
   Label break_target_;
-  const int base_id_;
+  int base_id_;
 };
 
 
 class Block FINAL : public BreakableStatement {
  public:
   DECLARE_NODE_TYPE(Block)
 
   void AddStatement(Statement* statement, Zone* zone) {
     statements_.Add(statement, zone);
   }
 
   ZoneList<Statement*>* statements() { return &statements_; }
   bool is_initializer_block() const { return is_initializer_block_; }
 
-  BailoutId DeclsId() const { return BailoutId(base_id() + 0); }
+  static int num_ids() { return parent_num_ids() + 1; }
+  BailoutId DeclsId() const { return BailoutId(local_id(0)); }
 
   virtual bool IsJump() const OVERRIDE {
     return !statements_.is_empty() && statements_.last()->IsJump()
         && labels() == NULL;  // Good enough as an approximation...
   }
 
   Scope* scope() const { return scope_; }
   void set_scope(Scope* scope) { scope_ = scope; }
 
  protected:
   Block(Zone* zone, ZoneList<const AstRawString*>* labels, int capacity,
-        bool is_initializer_block, int pos, IdGen* id_gen)
-      : BreakableStatement(zone, labels, TARGET_FOR_NAMED_ONLY, pos, num_ids(),
-                           id_gen),
+        bool is_initializer_block, int pos)
+      : BreakableStatement(zone, labels, TARGET_FOR_NAMED_ONLY, pos),
         statements_(capacity, zone),
         is_initializer_block_(is_initializer_block),
         scope_(NULL) {}
-
-  static int num_ids() { return 1; }
-  int base_id() const {
-    return BreakableStatement::base_id() + BreakableStatement::num_ids();
-  }
+  static int parent_num_ids() { return BreakableStatement::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   ZoneList<Statement*> statements_;
   bool is_initializer_block_;
   Scope* scope_;
 };
 
 
 class Declaration : public AstNode {
  public:
   VariableProxy* proxy() const { return proxy_; }
   VariableMode mode() const { return mode_; }
@@ skipping 227 matching lines @@
 
 class IterationStatement : public BreakableStatement {
  public:
   // Type testing & conversion.
   virtual IterationStatement* AsIterationStatement() FINAL OVERRIDE {
     return this;
   }
 
   Statement* body() const { return body_; }
 
-  BailoutId OsrEntryId() const { return BailoutId(base_id() + 0); }
+  static int num_ids() { return parent_num_ids() + 1; }
+  BailoutId OsrEntryId() const { return BailoutId(local_id(0)); }
   virtual BailoutId ContinueId() const = 0;
   virtual BailoutId StackCheckId() const = 0;
 
   // Code generation
   Label* continue_target()  { return &continue_target_; }
 
  protected:
-  IterationStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                     int num_ids_needed_by_subclass, IdGen* id_gen)
-      : BreakableStatement(zone, labels, TARGET_FOR_ANONYMOUS, pos,
-                           num_ids_needed_by_subclass + num_ids(), id_gen),
+  IterationStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : BreakableStatement(zone, labels, TARGET_FOR_ANONYMOUS, pos),
         body_(NULL) {}
-
-  void Initialize(Statement* body) {
-    body_ = body;
-  }
-
-  static int num_ids() { return 1; }
-  int base_id() const {
-    return BreakableStatement::base_id() + BreakableStatement::num_ids();
-  }
+  static int parent_num_ids() { return BreakableStatement::num_ids(); }
+  void Initialize(Statement* body) { body_ = body; }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Statement* body_;
   Label continue_target_;
 };
 
 
 class DoWhileStatement FINAL : public IterationStatement {
  public:
   DECLARE_NODE_TYPE(DoWhileStatement)
 
   void Initialize(Expression* cond, Statement* body) {
     IterationStatement::Initialize(body);
     cond_ = cond;
   }
 
   Expression* cond() const { return cond_; }
 
+  static int num_ids() { return parent_num_ids() + 2; }
   virtual BailoutId ContinueId() const OVERRIDE {
-    return BailoutId(base_id() + 0);
+    return BailoutId(local_id(0));
   }
   virtual BailoutId StackCheckId() const OVERRIDE { return BackEdgeId(); }
-  BailoutId BackEdgeId() const { return BailoutId(base_id() + 1); }
+  BailoutId BackEdgeId() const { return BailoutId(local_id(1)); }
 
  protected:
-  DoWhileStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                   IdGen* id_gen)
-      : IterationStatement(zone, labels, pos, num_ids(), id_gen), cond_(NULL) {}
-
-  static int num_ids() { return 2; }
-  int base_id() const {
-    return IterationStatement::base_id() + IterationStatement::num_ids();
-  }
+  DoWhileStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : IterationStatement(zone, labels, pos), cond_(NULL) {}
+  static int parent_num_ids() { return IterationStatement::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Expression* cond_;
 };
 
 
 class WhileStatement FINAL : public IterationStatement {
  public:
   DECLARE_NODE_TYPE(WhileStatement)
 
   void Initialize(Expression* cond, Statement* body) {
     IterationStatement::Initialize(body);
     cond_ = cond;
   }
 
   Expression* cond() const { return cond_; }
   bool may_have_function_literal() const {
     return may_have_function_literal_;
   }
   void set_may_have_function_literal(bool value) {
     may_have_function_literal_ = value;
   }
 
+  static int num_ids() { return parent_num_ids() + 1; }
   virtual BailoutId ContinueId() const OVERRIDE { return EntryId(); }
   virtual BailoutId StackCheckId() const OVERRIDE { return BodyId(); }
-  BailoutId BodyId() const { return BailoutId(base_id() + 0); }
+  BailoutId BodyId() const { return BailoutId(local_id(0)); }
 
  protected:
-  WhileStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                 IdGen* id_gen)
-      : IterationStatement(zone, labels, pos, num_ids(), id_gen),
+  WhileStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : IterationStatement(zone, labels, pos),
         cond_(NULL),
         may_have_function_literal_(true) {}
-
-  static int num_ids() { return 1; }
-  int base_id() const {
-    return IterationStatement::base_id() + IterationStatement::num_ids();
-  }
+  static int parent_num_ids() { return IterationStatement::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Expression* cond_;
 
   // True if there is a function literal subexpression in the condition.
   bool may_have_function_literal_;
 };
 
 
 class ForStatement FINAL : public IterationStatement {
  public:
   DECLARE_NODE_TYPE(ForStatement)
@@ skipping 12 matching lines @@
   Expression* cond() const { return cond_; }
   Statement* next() const { return next_; }
 
   bool may_have_function_literal() const {
     return may_have_function_literal_;
   }
   void set_may_have_function_literal(bool value) {
     may_have_function_literal_ = value;
   }
 
+  static int num_ids() { return parent_num_ids() + 2; }
   virtual BailoutId ContinueId() const OVERRIDE {
-    return BailoutId(base_id() + 0);
+    return BailoutId(local_id(0));
   }
   virtual BailoutId StackCheckId() const OVERRIDE { return BodyId(); }
-  BailoutId BodyId() const { return BailoutId(base_id() + 1); }
+  BailoutId BodyId() const { return BailoutId(local_id(1)); }
 
   bool is_fast_smi_loop() { return loop_variable_ != NULL; }
   Variable* loop_variable() { return loop_variable_; }
   void set_loop_variable(Variable* var) { loop_variable_ = var; }
 
  protected:
-  ForStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-               IdGen* id_gen)
-      : IterationStatement(zone, labels, pos, num_ids(), id_gen),
+  ForStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : IterationStatement(zone, labels, pos),
         init_(NULL),
         cond_(NULL),
         next_(NULL),
         may_have_function_literal_(true),
         loop_variable_(NULL) {}
-
-  static int num_ids() { return 2; }
-  int base_id() const {
-    return IterationStatement::base_id() + IterationStatement::num_ids();
-  }
+  static int parent_num_ids() { return IterationStatement::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Statement* init_;
   Expression* cond_;
   Statement* next_;
 
   // True if there is a function literal subexpression in the condition.
   bool may_have_function_literal_;
   Variable* loop_variable_;
 };
 
 
 class ForEachStatement : public IterationStatement {
  public:
   enum VisitMode {
     ENUMERATE,   // for (each in subject) body;
     ITERATE      // for (each of subject) body;
   };
 
   void Initialize(Expression* each, Expression* subject, Statement* body) {
     IterationStatement::Initialize(body);
     each_ = each;
     subject_ = subject;
   }
 
   Expression* each() const { return each_; }
   Expression* subject() const { return subject_; }
 
  protected:
-  ForEachStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                   int num_ids_needed_by_subclass, IdGen* id_gen)
-      : IterationStatement(zone, labels, pos, num_ids_needed_by_subclass,
-                           id_gen),
-        each_(NULL),
-        subject_(NULL) {}
+  ForEachStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : IterationStatement(zone, labels, pos), each_(NULL), subject_(NULL) {}
 
  private:
   Expression* each_;
   Expression* subject_;
 };
 
 
 class ForInStatement FINAL : public ForEachStatement {
  public:
   DECLARE_NODE_TYPE(ForInStatement)
@@ skipping 12 matching lines @@
 
   FeedbackVectorSlot ForInFeedbackSlot() {
     DCHECK(!for_in_feedback_slot_.IsInvalid());
     return for_in_feedback_slot_;
   }
 
   enum ForInType { FAST_FOR_IN, SLOW_FOR_IN };
   ForInType for_in_type() const { return for_in_type_; }
   void set_for_in_type(ForInType type) { for_in_type_ = type; }
 
-  BailoutId BodyId() const { return BailoutId(base_id() + 0); }
-  BailoutId PrepareId() const { return BailoutId(base_id() + 1); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId BodyId() const { return BailoutId(local_id(0)); }
+  BailoutId PrepareId() const { return BailoutId(local_id(1)); }
   virtual BailoutId ContinueId() const OVERRIDE { return EntryId(); }
   virtual BailoutId StackCheckId() const OVERRIDE { return BodyId(); }
 
  protected:
-  ForInStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                 IdGen* id_gen)
-      : ForEachStatement(zone, labels, pos, num_ids(), id_gen),
+  ForInStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : ForEachStatement(zone, labels, pos),
         for_in_type_(SLOW_FOR_IN),
         for_in_feedback_slot_(FeedbackVectorSlot::Invalid()) {}
-
-  static int num_ids() { return 2; }
-  int base_id() const {
-    return ForEachStatement::base_id() + ForEachStatement::num_ids();
-  }
+  static int parent_num_ids() { return ForEachStatement::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   ForInType for_in_type_;
   FeedbackVectorSlot for_in_feedback_slot_;
 };
 
 
 class ForOfStatement FINAL : public ForEachStatement {
  public:
   DECLARE_NODE_TYPE(ForOfStatement)
 
   void Initialize(Expression* each,
@@ skipping 30 matching lines @@
   }
 
   // each = result.value
   Expression* assign_each() const {
     return assign_each_;
   }
 
   virtual BailoutId ContinueId() const OVERRIDE { return EntryId(); }
   virtual BailoutId StackCheckId() const OVERRIDE { return BackEdgeId(); }
 
-  BailoutId BackEdgeId() const { return BailoutId(base_id() + 0); }
+  static int num_ids() { return parent_num_ids() + 1; }
+  BailoutId BackEdgeId() const { return BailoutId(local_id(0)); }
 
  protected:
-  ForOfStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                 IdGen* id_gen)
-      : ForEachStatement(zone, labels, pos, num_ids(), id_gen),
+  ForOfStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : ForEachStatement(zone, labels, pos),
         assign_iterator_(NULL),
         next_result_(NULL),
         result_done_(NULL),
         assign_each_(NULL) {}
-
-  static int num_ids() { return 1; }
-  int base_id() const {
-    return ForEachStatement::base_id() + ForEachStatement::num_ids();
-  }
+  static int parent_num_ids() { return ForEachStatement::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Expression* assign_iterator_;
   Expression* next_result_;
   Expression* result_done_;
   Expression* assign_each_;
 };
 
 
 class ExpressionStatement FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(ExpressionStatement)
@@ skipping 94 matching lines @@
   DECLARE_NODE_TYPE(CaseClause)
 
   bool is_default() const { return label_ == NULL; }
   Expression* label() const {
     CHECK(!is_default());
     return label_;
   }
   Label* body_target() { return &body_target_; }
   ZoneList<Statement*>* statements() const { return statements_; }
 
-  BailoutId EntryId() const { return BailoutId(base_id() + 0); }
-  TypeFeedbackId CompareId() { return TypeFeedbackId(base_id() + 1); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId EntryId() const { return BailoutId(local_id(0)); }
+  TypeFeedbackId CompareId() { return TypeFeedbackId(local_id(1)); }
 
   Type* compare_type() { return compare_type_; }
   void set_compare_type(Type* type) { compare_type_ = type; }
 
+ protected:
+  static int parent_num_ids() { return Expression::num_ids(); }
+
  private:
   CaseClause(Zone* zone, Expression* label, ZoneList<Statement*>* statements,
-             int pos, IdGen* id_gen);
-
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+             int pos);
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
 
   Expression* label_;
   Label body_target_;
   ZoneList<Statement*>* statements_;
   Type* compare_type_;
 };
 
 
 class SwitchStatement FINAL : public BreakableStatement {
  public:
   DECLARE_NODE_TYPE(SwitchStatement)
 
   void Initialize(Expression* tag, ZoneList<CaseClause*>* cases) {
     tag_ = tag;
     cases_ = cases;
   }
 
   Expression* tag() const { return tag_; }
   ZoneList<CaseClause*>* cases() const { return cases_; }
 
  protected:
-  SwitchStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos,
-                  IdGen* id_gen)
-      : BreakableStatement(zone, labels, TARGET_FOR_ANONYMOUS, pos, 0, id_gen),
+  SwitchStatement(Zone* zone, ZoneList<const AstRawString*>* labels, int pos)
+      : BreakableStatement(zone, labels, TARGET_FOR_ANONYMOUS, pos),
         tag_(NULL),
         cases_(NULL) {}
 
  private:
   Expression* tag_;
   ZoneList<CaseClause*>* cases_;
 };
 
 
 // If-statements always have non-null references to their then- and
@@ skipping 10 matching lines @@
 
   Expression* condition() const { return condition_; }
   Statement* then_statement() const { return then_statement_; }
   Statement* else_statement() const { return else_statement_; }
 
   virtual bool IsJump() const OVERRIDE {
     return HasThenStatement() && then_statement()->IsJump()
         && HasElseStatement() && else_statement()->IsJump();
   }
 
-  BailoutId IfId() const { return BailoutId(base_id() + 0); }
-  BailoutId ThenId() const { return BailoutId(base_id() + 1); }
-  BailoutId ElseId() const { return BailoutId(base_id() + 2); }
+  void set_base_id(int id) { base_id_ = id; }
+  static int num_ids() { return parent_num_ids() + 3; }
+  BailoutId IfId() const { return BailoutId(local_id(0)); }
+  BailoutId ThenId() const { return BailoutId(local_id(1)); }
+  BailoutId ElseId() const { return BailoutId(local_id(2)); }
 
  protected:
   IfStatement(Zone* zone, Expression* condition, Statement* then_statement,
-              Statement* else_statement, int pos, IdGen* id_gen)
+              Statement* else_statement, int pos)
       : Statement(zone, pos),
         condition_(condition),
         then_statement_(then_statement),
         else_statement_(else_statement),
-        base_id_(id_gen->ReserveIdRange(num_ids())) {}
+        base_id_(BailoutId::None().ToInt()) {}
+  static int parent_num_ids() { return 0; }
 
-  static int num_ids() { return 3; }
-  int base_id() const { return base_id_; }
+  int base_id() const {
+    DCHECK(!BailoutId(base_id_).IsNone());
+    return base_id_;
+  }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Expression* condition_;
   Statement* then_statement_;
   Statement* else_statement_;
-  const int base_id_;
+  int base_id_;
 };
 
 
 // NOTE: TargetCollectors are represented as nodes to fit in the target
 // stack in the compiler; this should probably be reworked.
 class TargetCollector FINAL : public AstNode {
  public:
   explicit TargetCollector(Zone* zone)
       : AstNode(RelocInfo::kNoPosition), targets_(0, zone) { }
 
@@ skipping 83 matching lines @@
 
  private:
   Block* finally_block_;
 };
 
 
 class DebuggerStatement FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(DebuggerStatement)
 
-  BailoutId DebugBreakId() const { return BailoutId(base_id() + 0); }
+  void set_base_id(int id) { base_id_ = id; }
+  static int num_ids() { return parent_num_ids() + 1; }
+  BailoutId DebugBreakId() const { return BailoutId(local_id(0)); }
 
  protected:
-  explicit DebuggerStatement(Zone* zone, int pos, IdGen* id_gen)
-      : Statement(zone, pos), base_id_(id_gen->ReserveIdRange(num_ids())) {}
+  explicit DebuggerStatement(Zone* zone, int pos)
+      : Statement(zone, pos), base_id_(BailoutId::None().ToInt()) {}
+  static int parent_num_ids() { return 0; }
 
-  static int num_ids() { return 1; }
-  int base_id() const { return base_id_; }
+  int base_id() const {
+    DCHECK(!BailoutId(base_id_).IsNone());
+    return base_id_;
+  }
 
  private:
-  const int base_id_;
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
+  int base_id_;
 };
 
 
 class EmptyStatement FINAL : public Statement {
  public:
   DECLARE_NODE_TYPE(EmptyStatement)
 
  protected:
   explicit EmptyStatement(Zone* zone, int pos): Statement(zone, pos) {}
 };
@@ skipping 25 matching lines @@
   }
 
   Handle<Object> value() const { return value_->value(); }
   const AstValue* raw_value() const { return value_; }
 
   // Support for using Literal as a HashMap key. NOTE: Currently, this works
   // only for string and number literals!
   uint32_t Hash();
   static bool Match(void* literal1, void* literal2);
 
+  static int num_ids() { return parent_num_ids() + 1; }
   TypeFeedbackId LiteralFeedbackId() const {
-    return TypeFeedbackId(base_id() + 0);
+    return TypeFeedbackId(local_id(0));
   }
 
  protected:
-  Literal(Zone* zone, const AstValue* value, int position, IdGen* id_gen)
-      : Expression(zone, position, num_ids(), id_gen), value_(value) {}
-
-  static int num_ids() { return 1; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  Literal(Zone* zone, const AstValue* value, int position)
+      : Expression(zone, position), value_(value) {}
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   const AstValue* value_;
 };
 
 
 // Base class for literals that needs space in the corresponding JSFunction.
 class MaterializedLiteral : public Expression {
  public:
   virtual MaterializedLiteral* AsMaterializedLiteral() { return this; }
 
   int literal_index() { return literal_index_; }
 
   int depth() const {
     // only callable after initialization.
     DCHECK(depth_ >= 1);
     return depth_;
   }
 
  protected:
-  MaterializedLiteral(Zone* zone, int literal_index, int pos,
-                      int num_ids_needed_by_subclass, IdGen* id_gen)
-      : Expression(zone, pos, num_ids_needed_by_subclass, id_gen),
+  MaterializedLiteral(Zone* zone, int literal_index, int pos)
+      : Expression(zone, pos),
         literal_index_(literal_index),
         is_simple_(false),
         depth_(0) {}
 
   // A materialized literal is simple if the values consist of only
   // constants and simple object and array literals.
   bool is_simple() const { return is_simple_; }
   void set_is_simple(bool is_simple) { is_simple_ = is_simple; }
   friend class CompileTimeValue;
 
@@ skipping 109 matching lines @@
   };
 
   struct Accessors: public ZoneObject {
     Accessors() : getter(NULL), setter(NULL) { }
     Expression* getter;
     Expression* setter;
   };
 
  protected:
   ObjectLiteral(Zone* zone, ZoneList<Property*>* properties, int literal_index,
-                int boilerplate_properties, bool has_function, int pos,
-                IdGen* id_gen)
-      : MaterializedLiteral(zone, literal_index, pos, 0, id_gen),
+                int boilerplate_properties, bool has_function, int pos)
+      : MaterializedLiteral(zone, literal_index, pos),
         properties_(properties),
         boilerplate_properties_(boilerplate_properties),
         fast_elements_(false),
         may_store_doubles_(false),
         has_function_(has_function) {}
 
  private:
   Handle<FixedArray> constant_properties_;
   ZoneList<Property*>* properties_;
   int boilerplate_properties_;
   bool fast_elements_;
   bool may_store_doubles_;
   bool has_function_;
 };
 
 
 // Node for capturing a regexp literal.
 class RegExpLiteral FINAL : public MaterializedLiteral {
  public:
   DECLARE_NODE_TYPE(RegExpLiteral)
 
   Handle<String> pattern() const { return pattern_->string(); }
   Handle<String> flags() const { return flags_->string(); }
 
  protected:
   RegExpLiteral(Zone* zone, const AstRawString* pattern,
-                const AstRawString* flags, int literal_index, int pos,
-                IdGen* id_gen)
-      : MaterializedLiteral(zone, literal_index, pos, 0, id_gen),
+                const AstRawString* flags, int literal_index, int pos)
+      : MaterializedLiteral(zone, literal_index, pos),
         pattern_(pattern),
         flags_(flags) {
     set_depth(1);
   }
 
  private:
   const AstRawString* pattern_;
   const AstRawString* flags_;
 };
 
 
 // An array literal has a literals object that is used
 // for minimizing the work when constructing it at runtime.
 class ArrayLiteral FINAL : public MaterializedLiteral {
  public:
   DECLARE_NODE_TYPE(ArrayLiteral)
 
   Handle<FixedArray> constant_elements() const { return constant_elements_; }
   ZoneList<Expression*>* values() const { return values_; }
 
+  // Unlike other AST nodes, this number of bailout IDs allocated for an
+  // ArrayLiteral can vary, so num_ids() is not a static method.
+  int num_ids() const { return parent_num_ids() + values()->length(); }
+
   // Return an AST id for an element that is used in simulate instructions.
-  BailoutId GetIdForElement(int i) { return BailoutId(base_id() + i); }
+  BailoutId GetIdForElement(int i) { return BailoutId(local_id(i)); }
 
   // Populate the constant elements fixed array.
   void BuildConstantElements(Isolate* isolate);
 
   // Assemble bitfield of flags for the CreateArrayLiteral helper.
   int ComputeFlags() const {
     int flags = depth() == 1 ? kShallowElements : kNoFlags;
     flags |= ArrayLiteral::kDisableMementos;
     return flags;
   }
 
   enum Flags {
     kNoFlags = 0,
     kShallowElements = 1,
     kDisableMementos = 1 << 1
   };
 
  protected:
   ArrayLiteral(Zone* zone, ZoneList<Expression*>* values, int literal_index,
-               int pos, IdGen* id_gen)
-      : MaterializedLiteral(zone, literal_index, pos, num_ids(values), id_gen),
-        values_(values) {}
-
-  static int num_ids(ZoneList<Expression*>* values) { return values->length(); }
-  int base_id() const {
-    return MaterializedLiteral::base_id() + MaterializedLiteral::num_ids();
-  }
+               int pos)
+      : MaterializedLiteral(zone, literal_index, pos), values_(values) {}
+  static int parent_num_ids() { return MaterializedLiteral::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Handle<FixedArray> constant_elements_;
   ZoneList<Expression*>* values_;
 };
 
 
 class VariableProxy FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(VariableProxy)
 
   virtual bool IsValidReferenceExpression() const OVERRIDE {
@@ skipping 35 matching lines @@
   }
   virtual void SetFirstICFeedbackSlot(FeedbackVectorICSlot slot) {
     variable_feedback_slot_ = slot;
   }
 
   FeedbackVectorICSlot VariableFeedbackSlot() {
     return variable_feedback_slot_;
   }
 
  protected:
-  VariableProxy(Zone* zone, Variable* var, int position, IdGen* id_gen);
+  VariableProxy(Zone* zone, Variable* var, int position);
 
   VariableProxy(Zone* zone, const AstRawString* name, bool is_this,
-                Interface* interface, int position, IdGen* id_gen);
+                Interface* interface, int position);
 
   bool is_this_ : 1;
   bool is_assigned_ : 1;
   bool is_resolved_ : 1;
   FeedbackVectorICSlot variable_feedback_slot_;
   union {
     const AstRawString* raw_name_;  // if !is_resolved_
     Variable* var_;                 // if is_resolved_
   };
   Interface* interface_;
 };
 
 
 class Property FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Property)
 
   virtual bool IsValidReferenceExpression() const OVERRIDE { return true; }
 
   Expression* obj() const { return obj_; }
   Expression* key() const { return key_; }
 
-  BailoutId LoadId() const { return BailoutId(base_id() + 0); }
-  TypeFeedbackId PropertyFeedbackId() { return TypeFeedbackId(base_id() + 1); }
-
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId LoadId() const { return BailoutId(local_id(0)); }
+  TypeFeedbackId PropertyFeedbackId() { return TypeFeedbackId(local_id(1)); }
 
   bool IsStringAccess() const { return is_string_access_; }
 
   // Type feedback information.
   virtual bool IsMonomorphic() OVERRIDE {
     return receiver_types_.length() == 1;
   }
   virtual SmallMapList* GetReceiverTypes() OVERRIDE {
     return &receiver_types_;
   }
@@ skipping 22 matching lines @@
   }
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) {
     property_feedback_slot_ = slot;
   }
 
   FeedbackVectorICSlot PropertyFeedbackSlot() const {
     return property_feedback_slot_;
   }
 
  protected:
-  Property(Zone* zone, Expression* obj, Expression* key, int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+  Property(Zone* zone, Expression* obj, Expression* key, int pos)
+      : Expression(zone, pos),
         is_for_call_(false),
         is_uninitialized_(false),
         is_string_access_(false),
         property_feedback_slot_(FeedbackVectorICSlot::Invalid()),
         obj_(obj),
         key_(key) {}
-
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   bool is_for_call_ : 1;
   bool is_uninitialized_ : 1;
   bool is_string_access_ : 1;
   FeedbackVectorICSlot property_feedback_slot_;
   Expression* obj_;
   Expression* key_;
   SmallMapList receiver_types_;
 };
 
 
@@ skipping 43 matching lines @@
   Handle<Cell> cell() { return cell_; }
 
   Handle<AllocationSite> allocation_site() { return allocation_site_; }
 
   void set_target(Handle<JSFunction> target) { target_ = target; }
   void set_allocation_site(Handle<AllocationSite> site) {
     allocation_site_ = site;
   }
   bool ComputeGlobalTarget(Handle<GlobalObject> global, LookupIterator* it);
 
-  BailoutId ReturnId() const { return BailoutId(base_id() + 0); }
-  BailoutId EvalOrLookupId() const { return BailoutId(base_id() + 1); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId ReturnId() const { return BailoutId(local_id(0)); }
+  BailoutId EvalOrLookupId() const { return BailoutId(local_id(1)); }
 
   enum CallType {
     POSSIBLY_EVAL_CALL,
     GLOBAL_CALL,
     LOOKUP_SLOT_CALL,
     PROPERTY_CALL,
     SUPER_CALL,
     OTHER_CALL
   };
 
   // Helpers to determine how to handle the call.
   CallType GetCallType(Isolate* isolate) const;
   bool IsUsingCallFeedbackSlot(Isolate* isolate) const;
 
 #ifdef DEBUG
   // Used to assert that the FullCodeGenerator records the return site.
   bool return_is_recorded_;
 #endif
 
  protected:
   Call(Zone* zone, Expression* expression, ZoneList<Expression*>* arguments,
-       int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+       int pos)
+      : Expression(zone, pos),
         call_feedback_slot_(FeedbackVectorICSlot::Invalid()),
         expression_(expression),
         arguments_(arguments) {
     if (expression->IsProperty()) {
       expression->AsProperty()->mark_for_call();
     }
   }
-
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   FeedbackVectorICSlot call_feedback_slot_;
   Expression* expression_;
   ZoneList<Expression*>* arguments_;
   Handle<JSFunction> target_;
   Handle<Cell> cell_;
   Handle<AllocationSite> allocation_site_;
 };
 
 
 class CallNew FINAL : public Expression {
@@ skipping 17 matching lines @@
     return CallNewFeedbackSlot().next();
   }
 
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
   virtual bool IsMonomorphic() OVERRIDE { return is_monomorphic_; }
   Handle<JSFunction> target() const { return target_; }
   Handle<AllocationSite> allocation_site() const {
     return allocation_site_;
   }
 
+  static int num_ids() { return parent_num_ids() + 1; }
   static int feedback_slots() { return 1; }
-
-  BailoutId ReturnId() const { return BailoutId(base_id() + 0); }
+  BailoutId ReturnId() const { return BailoutId(local_id(0)); }
 
  protected:
   CallNew(Zone* zone, Expression* expression, ZoneList<Expression*>* arguments,
-          int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+          int pos)
+      : Expression(zone, pos),
         expression_(expression),
         arguments_(arguments),
         is_monomorphic_(false),
         callnew_feedback_slot_(FeedbackVectorSlot::Invalid()) {}
 
-  static int num_ids() { return 1; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Expression* expression_;
   ZoneList<Expression*>* arguments_;
   bool is_monomorphic_;
   Handle<JSFunction> target_;
   Handle<AllocationSite> allocation_site_;
   FeedbackVectorSlot callnew_feedback_slot_;
 };
 
 
 // The CallRuntime class does not represent any official JavaScript
@@ skipping 16 matching lines @@
         0, (FLAG_vector_ics && is_jsruntime()) ? 1 : 0);
   }
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) {
     callruntime_feedback_slot_ = slot;
   }
 
   FeedbackVectorICSlot CallRuntimeFeedbackSlot() {
     return callruntime_feedback_slot_;
   }
 
+  static int num_ids() { return parent_num_ids() + 1; }
   TypeFeedbackId CallRuntimeFeedbackId() const {
-    return TypeFeedbackId(base_id() + 0);
+    return TypeFeedbackId(local_id(0));
   }
 
  protected:
   CallRuntime(Zone* zone, const AstRawString* name,
               const Runtime::Function* function,
-              ZoneList<Expression*>* arguments, int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+              ZoneList<Expression*>* arguments, int pos)
+      : Expression(zone, pos),
         raw_name_(name),
         function_(function),
         arguments_(arguments),
         callruntime_feedback_slot_(FeedbackVectorICSlot::Invalid()) {}
-
-  static int num_ids() { return 1; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   const AstRawString* raw_name_;
   const Runtime::Function* function_;
   ZoneList<Expression*>* arguments_;
   FeedbackVectorICSlot callruntime_feedback_slot_;
 };
 
 
 class UnaryOperation FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(UnaryOperation)
 
   Token::Value op() const { return op_; }
   Expression* expression() const { return expression_; }
 
   // For unary not (Token::NOT), the AST ids where true and false will
   // actually be materialized, respectively.
-  BailoutId MaterializeTrueId() const { return BailoutId(base_id() + 0); }
-  BailoutId MaterializeFalseId() const { return BailoutId(base_id() + 1); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId MaterializeTrueId() const { return BailoutId(local_id(0)); }
+  BailoutId MaterializeFalseId() const { return BailoutId(local_id(1)); }
 
   virtual void RecordToBooleanTypeFeedback(
       TypeFeedbackOracle* oracle) OVERRIDE;
 
  protected:
-  UnaryOperation(Zone* zone, Token::Value op, Expression* expression, int pos,
-                 IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
-        op_(op),
-        expression_(expression) {
+  UnaryOperation(Zone* zone, Token::Value op, Expression* expression, int pos)
+      : Expression(zone, pos), op_(op), expression_(expression) {
     DCHECK(Token::IsUnaryOp(op));
   }
-
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Token::Value op_;
   Expression* expression_;
 };
 
 
 class BinaryOperation FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(BinaryOperation)
 
   virtual bool ResultOverwriteAllowed() const OVERRIDE;
 
   Token::Value op() const { return static_cast<Token::Value>(op_); }
   Expression* left() const { return left_; }
   Expression* right() const { return right_; }
   Handle<AllocationSite> allocation_site() const { return allocation_site_; }
   void set_allocation_site(Handle<AllocationSite> allocation_site) {
     allocation_site_ = allocation_site;
   }
 
   // The short-circuit logical operations need an AST ID for their
   // right-hand subexpression.
-  BailoutId RightId() const { return BailoutId(base_id() + 0); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId RightId() const { return BailoutId(local_id(0)); }
 
   TypeFeedbackId BinaryOperationFeedbackId() const {
-    return TypeFeedbackId(base_id() + 1);
+    return TypeFeedbackId(local_id(1));
   }
   Maybe<int> fixed_right_arg() const {
     return has_fixed_right_arg_ ? Maybe<int>(fixed_right_arg_value_)
                                 : Maybe<int>();
   }
   void set_fixed_right_arg(Maybe<int> arg) {
     has_fixed_right_arg_ = arg.has_value;
     if (arg.has_value) fixed_right_arg_value_ = arg.value;
   }
 
   virtual void RecordToBooleanTypeFeedback(
       TypeFeedbackOracle* oracle) OVERRIDE;
 
  protected:
   BinaryOperation(Zone* zone, Token::Value op, Expression* left,
-                  Expression* right, int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+                  Expression* right, int pos)
+      : Expression(zone, pos),
         op_(static_cast<byte>(op)),
         left_(left),
         right_(right) {
     DCHECK(Token::IsBinaryOp(op));
   }
-
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   const byte op_;  // actually Token::Value
   // TODO(rossberg): the fixed arg should probably be represented as a Constant
   // type for the RHS. Currenty it's actually a Maybe<int>
   bool has_fixed_right_arg_;
   int fixed_right_arg_value_;
   Expression* left_;
   Expression* right_;
   Handle<AllocationSite> allocation_site_;
 };
 
@@ skipping 20 matching lines @@
   }
   virtual IcCheckType GetKeyType() OVERRIDE { return key_type_; }
   virtual KeyedAccessStoreMode GetStoreMode() OVERRIDE {
     return store_mode_;
   }
   Type* type() const { return type_; }
   void set_key_type(IcCheckType type) { key_type_ = type; }
   void set_store_mode(KeyedAccessStoreMode mode) { store_mode_ = mode; }
   void set_type(Type* type) { type_ = type; }
 
-  BailoutId AssignmentId() const { return BailoutId(base_id() + 0); }
+  static int num_ids() { return parent_num_ids() + 3; }
+  BailoutId AssignmentId() const { return BailoutId(local_id(0)); }
   TypeFeedbackId CountBinOpFeedbackId() const {
-    return TypeFeedbackId(base_id() + 1);
+    return TypeFeedbackId(local_id(1));
   }
   TypeFeedbackId CountStoreFeedbackId() const {
-    return TypeFeedbackId(base_id() + 2);
+    return TypeFeedbackId(local_id(2));
   }
 
  protected:
   CountOperation(Zone* zone, Token::Value op, bool is_prefix, Expression* expr,
-                 int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+                 int pos)
+      : Expression(zone, pos),
         op_(op),
         is_prefix_(is_prefix),
         key_type_(ELEMENT),
         store_mode_(STANDARD_STORE),
         expression_(expr) {}
-
-  static int num_ids() { return 3; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Token::Value op_;
   bool is_prefix_ : 1;
   IcCheckType key_type_ : 1;
   KeyedAccessStoreMode store_mode_ : 5;  // Windows treats as signed,
                                          // must have extra bit.
   Type* type_;
   Expression* expression_;
   SmallMapList receiver_types_;
 };
 
 
 class CompareOperation FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CompareOperation)
 
   Token::Value op() const { return op_; }
   Expression* left() const { return left_; }
   Expression* right() const { return right_; }
 
   // Type feedback information.
+  static int num_ids() { return parent_num_ids() + 1; }
   TypeFeedbackId CompareOperationFeedbackId() const {
-    return TypeFeedbackId(base_id() + 0);
+    return TypeFeedbackId(local_id(0));
   }
   Type* combined_type() const { return combined_type_; }
   void set_combined_type(Type* type) { combined_type_ = type; }
 
   // Match special cases.
   bool IsLiteralCompareTypeof(Expression** expr, Handle<String>* check);
   bool IsLiteralCompareUndefined(Expression** expr, Isolate* isolate);
   bool IsLiteralCompareNull(Expression** expr);
 
  protected:
   CompareOperation(Zone* zone, Token::Value op, Expression* left,
-                   Expression* right, int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+                   Expression* right, int pos)
+      : Expression(zone, pos),
         op_(op),
         left_(left),
         right_(right),
         combined_type_(Type::None(zone)) {
     DCHECK(Token::IsCompareOp(op));
   }
-
-  static int num_ids() { return 1; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Token::Value op_;
   Expression* left_;
   Expression* right_;
 
   Type* combined_type_;
 };
 
 
 class Conditional FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Conditional)
 
   Expression* condition() const { return condition_; }
   Expression* then_expression() const { return then_expression_; }
   Expression* else_expression() const { return else_expression_; }
 
-  BailoutId ThenId() const { return BailoutId(base_id() + 0); }
-  BailoutId ElseId() const { return BailoutId(base_id() + 1); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId ThenId() const { return BailoutId(local_id(0)); }
+  BailoutId ElseId() const { return BailoutId(local_id(1)); }
 
  protected:
   Conditional(Zone* zone, Expression* condition, Expression* then_expression,
-              Expression* else_expression, int position, IdGen* id_gen)
-      : Expression(zone, position, num_ids(), id_gen),
+              Expression* else_expression, int position)
+      : Expression(zone, position),
         condition_(condition),
         then_expression_(then_expression),
         else_expression_(else_expression) {}
-
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   Expression* condition_;
   Expression* then_expression_;
   Expression* else_expression_;
 };
 
 
 class Assignment FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Assignment)
 
   Assignment* AsSimpleAssignment() { return !is_compound() ? this : NULL; }
 
   Token::Value binary_op() const;
 
   Token::Value op() const { return op_; }
   Expression* target() const { return target_; }
   Expression* value() const { return value_; }
   BinaryOperation* binary_operation() const { return binary_operation_; }
 
   // This check relies on the definition order of token in token.h.
   bool is_compound() const { return op() > Token::ASSIGN; }
 
-  BailoutId AssignmentId() const { return BailoutId(base_id() + 0); }
+  static int num_ids() { return parent_num_ids() + 2; }
+  BailoutId AssignmentId() const { return BailoutId(local_id(0)); }
 
   // Type feedback information.
-  TypeFeedbackId AssignmentFeedbackId() {
-    return TypeFeedbackId(base_id() + 1);
-  }
+  TypeFeedbackId AssignmentFeedbackId() { return TypeFeedbackId(local_id(1)); }
   virtual bool IsMonomorphic() OVERRIDE {
     return receiver_types_.length() == 1;
   }
   bool IsUninitialized() { return is_uninitialized_; }
   bool HasNoTypeInformation() {
     return is_uninitialized_;
   }
   virtual SmallMapList* GetReceiverTypes() OVERRIDE {
     return &receiver_types_;
   }
   virtual IcCheckType GetKeyType() OVERRIDE { return key_type_; }
   virtual KeyedAccessStoreMode GetStoreMode() OVERRIDE {
     return store_mode_;
   }
   void set_is_uninitialized(bool b) { is_uninitialized_ = b; }
   void set_key_type(IcCheckType key_type) { key_type_ = key_type; }
   void set_store_mode(KeyedAccessStoreMode mode) { store_mode_ = mode; }
 
  protected:
   Assignment(Zone* zone, Token::Value op, Expression* target, Expression* value,
-             int pos, IdGen* id_gen);
+             int pos);
+  static int parent_num_ids() { return Expression::num_ids(); }
 
-  static int num_ids() { return 2; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
-
-  template<class Visitor>
-  void Init(Zone* zone, AstNodeFactory<Visitor>* factory) {
+  template <class Visitor>
+  void Init(AstNodeFactory<Visitor>* factory) {
     DCHECK(Token::IsAssignmentOp(op_));
     if (is_compound()) {
       binary_operation_ = factory->NewBinaryOperation(
           binary_op(), target_, value_, position() + 1);
     }
   }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   bool is_uninitialized_ : 1;
   IcCheckType key_type_ : 1;
   KeyedAccessStoreMode store_mode_ : 5;  // Windows treats as signed,
                                          // must have extra bit.
   Token::Value op_;
   Expression* target_;
   Expression* value_;
   BinaryOperation* binary_operation_;
   SmallMapList receiver_types_;
 };
@@ skipping 40 matching lines @@
   }
 
   FeedbackVectorICSlot DoneFeedbackSlot() {
     return KeyedLoadFeedbackSlot().next();
   }
 
   FeedbackVectorICSlot ValueFeedbackSlot() { return DoneFeedbackSlot().next(); }
 
  protected:
   Yield(Zone* zone, Expression* generator_object, Expression* expression,
-        Kind yield_kind, int pos, IdGen* id_gen)
-      : Expression(zone, pos, 0, id_gen),
+        Kind yield_kind, int pos)
+      : Expression(zone, pos),
         generator_object_(generator_object),
         expression_(expression),
         yield_kind_(yield_kind),
         index_(-1),
         yield_first_feedback_slot_(FeedbackVectorICSlot::Invalid()) {}
 
  private:
   Expression* generator_object_;
   Expression* expression_;
   Kind yield_kind_;
   int index_;
   FeedbackVectorICSlot yield_first_feedback_slot_;
 };
 
 
 class Throw FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Throw)
 
   Expression* exception() const { return exception_; }
 
  protected:
-  Throw(Zone* zone, Expression* exception, int pos, IdGen* id_gen)
-      : Expression(zone, pos, 0, id_gen), exception_(exception) {}
+  Throw(Zone* zone, Expression* exception, int pos)
+      : Expression(zone, pos), exception_(exception) {}
 
  private:
   Expression* exception_;
 };
 
 
 class FunctionLiteral FINAL : public Expression {
  public:
   enum FunctionType {
     ANONYMOUS_EXPRESSION,
@@ skipping 133 matching lines @@
 
  protected:
   FunctionLiteral(Zone* zone, const AstRawString* name,
                   AstValueFactory* ast_value_factory, Scope* scope,
                   ZoneList<Statement*>* body, int materialized_literal_count,
                   int expected_property_count, int handler_count,
                   int parameter_count, FunctionType function_type,
                   ParameterFlag has_duplicate_parameters,
                   IsFunctionFlag is_function,
                   IsParenthesizedFlag is_parenthesized, FunctionKind kind,
-                  int position, IdGen* id_gen)
-      : Expression(zone, position, 0, id_gen),
+                  int position)
+      : Expression(zone, position),
         raw_name_(name),
         scope_(scope),
         body_(body),
         raw_inferred_name_(ast_value_factory->empty_string()),
         dont_optimize_reason_(kNoReason),
         materialized_literal_count_(materialized_literal_count),
         expected_property_count_(expected_property_count),
         handler_count_(handler_count),
         parameter_count_(parameter_count),
         function_token_position_(RelocInfo::kNoPosition) {
@@ skipping 45 matching lines @@
   const AstRawString* raw_name() const { return raw_name_; }
   Expression* extends() const { return extends_; }
   Expression* constructor() const { return constructor_; }
   ZoneList<Property*>* properties() const { return properties_; }
   int start_position() const { return position(); }
   int end_position() const { return end_position_; }
 
  protected:
   ClassLiteral(Zone* zone, const AstRawString* name, Expression* extends,
                Expression* constructor, ZoneList<Property*>* properties,
-               int start_position, int end_position, IdGen* id_gen)
-      : Expression(zone, start_position, 0, id_gen),
+               int start_position, int end_position)
+      : Expression(zone, start_position),
         raw_name_(name),
         extends_(extends),
         constructor_(constructor),
         properties_(properties),
         end_position_(end_position) {}
 
  private:
   const AstRawString* raw_name_;
   Expression* extends_;
   Expression* constructor_;
   ZoneList<Property*>* properties_;
   int end_position_;
 };
 
 
 class NativeFunctionLiteral FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(NativeFunctionLiteral)
 
   Handle<String> name() const { return name_->string(); }
   v8::Extension* extension() const { return extension_; }
 
  protected:
   NativeFunctionLiteral(Zone* zone, const AstRawString* name,
-                        v8::Extension* extension, int pos, IdGen* id_gen)
-      : Expression(zone, pos, 0, id_gen), name_(name), extension_(extension) {}
+                        v8::Extension* extension, int pos)
+      : Expression(zone, pos), name_(name), extension_(extension) {}
 
  private:
   const AstRawString* name_;
   v8::Extension* extension_;
 };
 
 
 class ThisFunction FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(ThisFunction)
 
  protected:
-  ThisFunction(Zone* zone, int pos, IdGen* id_gen)
-      : Expression(zone, pos, 0, id_gen) {}
+  ThisFunction(Zone* zone, int pos) : Expression(zone, pos) {}
 };
 
 
 class SuperReference FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(SuperReference)
 
   VariableProxy* this_var() const { return this_var_; }
 
-  TypeFeedbackId HomeObjectFeedbackId() {
-    return TypeFeedbackId(base_id() + 0);
-  }
+  static int num_ids() { return parent_num_ids() + 1; }
+  TypeFeedbackId HomeObjectFeedbackId() { return TypeFeedbackId(local_id(0)); }
 
   // Type feedback information.
   virtual FeedbackVectorRequirements ComputeFeedbackRequirements() {
     return FeedbackVectorRequirements(0, FLAG_vector_ics ? 1 : 0);
   }
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) {
     homeobject_feedback_slot_ = slot;
   }
 
   FeedbackVectorICSlot HomeObjectFeedbackSlot() {
     DCHECK(!FLAG_vector_ics || !homeobject_feedback_slot_.IsInvalid());
     return homeobject_feedback_slot_;
   }
 
  protected:
-  SuperReference(Zone* zone, VariableProxy* this_var, int pos, IdGen* id_gen)
-      : Expression(zone, pos, num_ids(), id_gen),
+  SuperReference(Zone* zone, VariableProxy* this_var, int pos)
+      : Expression(zone, pos),
         this_var_(this_var),
         homeobject_feedback_slot_(FeedbackVectorICSlot::Invalid()) {
     DCHECK(this_var->is_this());
   }
-
-  static int num_ids() { return 1; }
-  int base_id() const { return Expression::base_id() + Expression::num_ids(); }
+  static int parent_num_ids() { return Expression::num_ids(); }
 
  private:
+  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
+
   VariableProxy* this_var_;
   FeedbackVectorICSlot homeobject_feedback_slot_;
 };
 
 
 #undef DECLARE_NODE_TYPE
 
 
 // ----------------------------------------------------------------------------
 // Regular expressions
@@ skipping 481 matching lines @@
 };
 
 
 
 // ----------------------------------------------------------------------------
 // AstNode factory
 
 template<class Visitor>
 class AstNodeFactory FINAL BASE_EMBEDDED {
  public:
-  AstNodeFactory(Zone* zone, AstValueFactory* ast_value_factory,
-                 AstNode::IdGen* id_gen)
-      : zone_(zone), ast_value_factory_(ast_value_factory), id_gen_(id_gen) {}
+  explicit AstNodeFactory(AstValueFactory* ast_value_factory)
+      : zone_(ast_value_factory->zone()),
+        ast_value_factory_(ast_value_factory) {}
 
   Visitor* visitor() { return &visitor_; }
 
 #define VISIT_AND_RETURN(NodeType, node) \
   visitor_.Visit##NodeType((node)); \
   return node;
 
   VariableDeclaration* NewVariableDeclaration(VariableProxy* proxy,
                                               VariableMode mode,
                                               Scope* scope,
@@ skipping 57 matching lines @@
 
   ModuleUrl* NewModuleUrl(Handle<String> url, int pos) {
     ModuleUrl* module = new(zone_) ModuleUrl(zone_, url, pos);
     VISIT_AND_RETURN(ModuleUrl, module)
   }
 
   Block* NewBlock(ZoneList<const AstRawString*>* labels,
                   int capacity,
                   bool is_initializer_block,
                   int pos) {
-    Block* block = new (zone_)
-        Block(zone_, labels, capacity, is_initializer_block, pos, id_gen_);
+    Block* block =
+        new (zone_) Block(zone_, labels, capacity, is_initializer_block, pos);
     VISIT_AND_RETURN(Block, block)
   }
 
 #define STATEMENT_WITH_LABELS(NodeType)                                     \
   NodeType* New##NodeType(ZoneList<const AstRawString*>* labels, int pos) { \
-    NodeType* stmt = new (zone_) NodeType(zone_, labels, pos, id_gen_);     \
+    NodeType* stmt = new (zone_) NodeType(zone_, labels, pos);              \
     VISIT_AND_RETURN(NodeType, stmt);                                       \
   }
   STATEMENT_WITH_LABELS(DoWhileStatement)
   STATEMENT_WITH_LABELS(WhileStatement)
   STATEMENT_WITH_LABELS(ForStatement)
   STATEMENT_WITH_LABELS(SwitchStatement)
 #undef STATEMENT_WITH_LABELS
 
   ForEachStatement* NewForEachStatement(ForEachStatement::VisitMode visit_mode,
                                         ZoneList<const AstRawString*>* labels,
                                         int pos) {
     switch (visit_mode) {
       case ForEachStatement::ENUMERATE: {
-        ForInStatement* stmt =
-            new (zone_) ForInStatement(zone_, labels, pos, id_gen_);
+        ForInStatement* stmt = new (zone_) ForInStatement(zone_, labels, pos);
         VISIT_AND_RETURN(ForInStatement, stmt);
       }
       case ForEachStatement::ITERATE: {
-        ForOfStatement* stmt =
-            new (zone_) ForOfStatement(zone_, labels, pos, id_gen_);
+        ForOfStatement* stmt = new (zone_) ForOfStatement(zone_, labels, pos);
         VISIT_AND_RETURN(ForOfStatement, stmt);
       }
     }
     UNREACHABLE();
     return NULL;
   }
 
   ModuleStatement* NewModuleStatement(
       VariableProxy* proxy, Block* body, int pos) {
     ModuleStatement* stmt = new(zone_) ModuleStatement(zone_, proxy, body, pos);
@@ skipping 27 matching lines @@
                                   int pos) {
     WithStatement* stmt = new(zone_) WithStatement(
         zone_, scope, expression, statement, pos);
     VISIT_AND_RETURN(WithStatement, stmt)
   }
 
   IfStatement* NewIfStatement(Expression* condition,
                               Statement* then_statement,
                               Statement* else_statement,
                               int pos) {
-    IfStatement* stmt = new (zone_) IfStatement(
-        zone_, condition, then_statement, else_statement, pos, id_gen_);
+    IfStatement* stmt = new (zone_)
+        IfStatement(zone_, condition, then_statement, else_statement, pos);
     VISIT_AND_RETURN(IfStatement, stmt)
   }
 
   TryCatchStatement* NewTryCatchStatement(int index,
                                           Block* try_block,
                                           Scope* scope,
                                           Variable* variable,
                                           Block* catch_block,
                                           int pos) {
     TryCatchStatement* stmt = new(zone_) TryCatchStatement(
         zone_, index, try_block, scope, variable, catch_block, pos);
     VISIT_AND_RETURN(TryCatchStatement, stmt)
   }
 
   TryFinallyStatement* NewTryFinallyStatement(int index,
                                               Block* try_block,
                                               Block* finally_block,
                                               int pos) {
     TryFinallyStatement* stmt = new(zone_) TryFinallyStatement(
         zone_, index, try_block, finally_block, pos);
     VISIT_AND_RETURN(TryFinallyStatement, stmt)
   }
 
   DebuggerStatement* NewDebuggerStatement(int pos) {
-    DebuggerStatement* stmt =
-        new (zone_) DebuggerStatement(zone_, pos, id_gen_);
+    DebuggerStatement* stmt = new (zone_) DebuggerStatement(zone_, pos);
     VISIT_AND_RETURN(DebuggerStatement, stmt)
   }
 
   EmptyStatement* NewEmptyStatement(int pos) {
     return new(zone_) EmptyStatement(zone_, pos);
   }
 
   CaseClause* NewCaseClause(
       Expression* label, ZoneList<Statement*>* statements, int pos) {
-    CaseClause* clause =
-        new (zone_) CaseClause(zone_, label, statements, pos, id_gen_);
+    CaseClause* clause = new (zone_) CaseClause(zone_, label, statements, pos);
     VISIT_AND_RETURN(CaseClause, clause)
   }
 
   Literal* NewStringLiteral(const AstRawString* string, int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewString(string), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewString(string), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   // A JavaScript symbol (ECMA-262 edition 6).
   Literal* NewSymbolLiteral(const char* name, int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewSymbol(name), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewSymbol(name), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewNumberLiteral(double number, int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewNumber(number), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewNumber(number), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewSmiLiteral(int number, int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewSmi(number), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewSmi(number), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewBooleanLiteral(bool b, int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewBoolean(b), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewBoolean(b), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewStringListLiteral(ZoneList<const AstRawString*>* strings,
                                 int pos) {
-    Literal* lit = new (zone_) Literal(
-        zone_, ast_value_factory_->NewStringList(strings), pos, id_gen_);
+    Literal* lit = new (zone_)
+        Literal(zone_, ast_value_factory_->NewStringList(strings), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewNullLiteral(int pos) {
     Literal* lit =
-        new (zone_) Literal(zone_, ast_value_factory_->NewNull(), pos, id_gen_);
+        new (zone_) Literal(zone_, ast_value_factory_->NewNull(), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewUndefinedLiteral(int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewUndefined(), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewUndefined(), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   Literal* NewTheHoleLiteral(int pos) {
-    Literal* lit = new (zone_)
-        Literal(zone_, ast_value_factory_->NewTheHole(), pos, id_gen_);
+    Literal* lit =
+        new (zone_) Literal(zone_, ast_value_factory_->NewTheHole(), pos);
     VISIT_AND_RETURN(Literal, lit)
   }
 
   ObjectLiteral* NewObjectLiteral(
       ZoneList<ObjectLiteral::Property*>* properties,
       int literal_index,
       int boilerplate_properties,
       bool has_function,
       int pos) {
-    ObjectLiteral* lit = new (zone_)
-        ObjectLiteral(zone_, properties, literal_index, boilerplate_properties,
-                      has_function, pos, id_gen_);
+    ObjectLiteral* lit =
+        new (zone_) ObjectLiteral(zone_, properties, literal_index,
+                                  boilerplate_properties, has_function, pos);
     VISIT_AND_RETURN(ObjectLiteral, lit)
   }
 
   ObjectLiteral::Property* NewObjectLiteralProperty(Literal* key,
                                                     Expression* value,
                                                     bool is_static) {
     return new (zone_) ObjectLiteral::Property(zone_, ast_value_factory_, key,
                                                value, is_static);
   }
 
   ObjectLiteral::Property* NewObjectLiteralProperty(bool is_getter,
                                                     FunctionLiteral* value,
                                                     int pos, bool is_static) {
     ObjectLiteral::Property* prop =
         new (zone_) ObjectLiteral::Property(zone_, is_getter, value, is_static);
     prop->set_key(NewStringLiteral(value->raw_name(), pos));
     return prop;  // Not an AST node, will not be visited.
   }
 
   RegExpLiteral* NewRegExpLiteral(const AstRawString* pattern,
                                   const AstRawString* flags,
                                   int literal_index,
                                   int pos) {
-    RegExpLiteral* lit = new (zone_)
-        RegExpLiteral(zone_, pattern, flags, literal_index, pos, id_gen_);
+    RegExpLiteral* lit =
+        new (zone_) RegExpLiteral(zone_, pattern, flags, literal_index, pos);
     VISIT_AND_RETURN(RegExpLiteral, lit);
   }
 
   ArrayLiteral* NewArrayLiteral(ZoneList<Expression*>* values,
                                 int literal_index,
                                 int pos) {
     ArrayLiteral* lit =
-        new (zone_) ArrayLiteral(zone_, values, literal_index, pos, id_gen_);
+        new (zone_) ArrayLiteral(zone_, values, literal_index, pos);
     VISIT_AND_RETURN(ArrayLiteral, lit)
   }
 
   VariableProxy* NewVariableProxy(Variable* var,
                                   int pos = RelocInfo::kNoPosition) {
-    VariableProxy* proxy = new (zone_) VariableProxy(zone_, var, pos, id_gen_);
+    VariableProxy* proxy = new (zone_) VariableProxy(zone_, var, pos);
     VISIT_AND_RETURN(VariableProxy, proxy)
   }
 
   VariableProxy* NewVariableProxy(const AstRawString* name,
                                   bool is_this,
                                   Interface* interface = Interface::NewValue(),
                                   int position = RelocInfo::kNoPosition) {
-    VariableProxy* proxy = new (zone_)
-        VariableProxy(zone_, name, is_this, interface, position, id_gen_);
+    VariableProxy* proxy =
+        new (zone_) VariableProxy(zone_, name, is_this, interface, position);
     VISIT_AND_RETURN(VariableProxy, proxy)
   }
 
   Property* NewProperty(Expression* obj, Expression* key, int pos) {
-    Property* prop = new (zone_) Property(zone_, obj, key, pos, id_gen_);
+    Property* prop = new (zone_) Property(zone_, obj, key, pos);
     VISIT_AND_RETURN(Property, prop)
   }
 
   Call* NewCall(Expression* expression,
                 ZoneList<Expression*>* arguments,
                 int pos) {
-    Call* call = new (zone_) Call(zone_, expression, arguments, pos, id_gen_);
+    Call* call = new (zone_) Call(zone_, expression, arguments, pos);
     VISIT_AND_RETURN(Call, call)
   }
 
   CallNew* NewCallNew(Expression* expression,
                       ZoneList<Expression*>* arguments,
                       int pos) {
-    CallNew* call =
-        new (zone_) CallNew(zone_, expression, arguments, pos, id_gen_);
+    CallNew* call = new (zone_) CallNew(zone_, expression, arguments, pos);
     VISIT_AND_RETURN(CallNew, call)
   }
 
   CallRuntime* NewCallRuntime(const AstRawString* name,
                               const Runtime::Function* function,
                               ZoneList<Expression*>* arguments,
                               int pos) {
     CallRuntime* call =
-        new (zone_) CallRuntime(zone_, name, function, arguments, pos, id_gen_);
+        new (zone_) CallRuntime(zone_, name, function, arguments, pos);
     VISIT_AND_RETURN(CallRuntime, call)
   }
 
   UnaryOperation* NewUnaryOperation(Token::Value op,
                                     Expression* expression,
                                     int pos) {
     UnaryOperation* node =
-        new (zone_) UnaryOperation(zone_, op, expression, pos, id_gen_);
+        new (zone_) UnaryOperation(zone_, op, expression, pos);
     VISIT_AND_RETURN(UnaryOperation, node)
   }
 
   BinaryOperation* NewBinaryOperation(Token::Value op,
                                       Expression* left,
                                       Expression* right,
                                       int pos) {
     BinaryOperation* node =
-        new (zone_) BinaryOperation(zone_, op, left, right, pos, id_gen_);
+        new (zone_) BinaryOperation(zone_, op, left, right, pos);
     VISIT_AND_RETURN(BinaryOperation, node)
   }
 
   CountOperation* NewCountOperation(Token::Value op,
                                     bool is_prefix,
                                     Expression* expr,
                                     int pos) {
     CountOperation* node =
-        new (zone_) CountOperation(zone_, op, is_prefix, expr, pos, id_gen_);
+        new (zone_) CountOperation(zone_, op, is_prefix, expr, pos);
     VISIT_AND_RETURN(CountOperation, node)
   }
 
   CompareOperation* NewCompareOperation(Token::Value op,
                                         Expression* left,
                                         Expression* right,
                                         int pos) {
     CompareOperation* node =
-        new (zone_) CompareOperation(zone_, op, left, right, pos, id_gen_);
+        new (zone_) CompareOperation(zone_, op, left, right, pos);
     VISIT_AND_RETURN(CompareOperation, node)
   }
 
   Conditional* NewConditional(Expression* condition,
                               Expression* then_expression,
                               Expression* else_expression,
                               int position) {
     Conditional* cond = new (zone_) Conditional(
-        zone_, condition, then_expression, else_expression, position, id_gen_);
+        zone_, condition, then_expression, else_expression, position);
     VISIT_AND_RETURN(Conditional, cond)
   }
 
   Assignment* NewAssignment(Token::Value op,
                             Expression* target,
                             Expression* value,
                             int pos) {
-    Assignment* assign =
-        new (zone_) Assignment(zone_, op, target, value, pos, id_gen_);
-    assign->Init(zone_, this);
+    Assignment* assign = new (zone_) Assignment(zone_, op, target, value, pos);
+    assign->Init(this);
     VISIT_AND_RETURN(Assignment, assign)
   }
 
   Yield* NewYield(Expression *generator_object,
                   Expression* expression,
                   Yield::Kind yield_kind,
                   int pos) {
     if (!expression) expression = NewUndefinedLiteral(pos);
-    Yield* yield = new (zone_)
-        Yield(zone_, generator_object, expression, yield_kind, pos, id_gen_);
+    Yield* yield =
+        new (zone_) Yield(zone_, generator_object, expression, yield_kind, pos);
     VISIT_AND_RETURN(Yield, yield)
   }
 
   Throw* NewThrow(Expression* exception, int pos) {
-    Throw* t = new (zone_) Throw(zone_, exception, pos, id_gen_);
+    Throw* t = new (zone_) Throw(zone_, exception, pos);
     VISIT_AND_RETURN(Throw, t)
   }
 
   FunctionLiteral* NewFunctionLiteral(
       const AstRawString* name, AstValueFactory* ast_value_factory,
       Scope* scope, ZoneList<Statement*>* body, int materialized_literal_count,
       int expected_property_count, int handler_count, int parameter_count,
       FunctionLiteral::ParameterFlag has_duplicate_parameters,
       FunctionLiteral::FunctionType function_type,
       FunctionLiteral::IsFunctionFlag is_function,
       FunctionLiteral::IsParenthesizedFlag is_parenthesized, FunctionKind kind,
       int position) {
     FunctionLiteral* lit = new (zone_) FunctionLiteral(
         zone_, name, ast_value_factory, scope, body, materialized_literal_count,
         expected_property_count, handler_count, parameter_count, function_type,
-        has_duplicate_parameters, is_function, is_parenthesized, kind, position,
-        id_gen_);
+        has_duplicate_parameters, is_function, is_parenthesized, kind,
+        position);
     // Top-level literal doesn't count for the AST's properties.
     if (is_function == FunctionLiteral::kIsFunction) {
       visitor_.VisitFunctionLiteral(lit);
     }
     return lit;
   }
 
   ClassLiteral* NewClassLiteral(const AstRawString* name, Expression* extends,
                                 Expression* constructor,
                                 ZoneList<ObjectLiteral::Property*>* properties,
                                 int start_position, int end_position) {
     ClassLiteral* lit =
         new (zone_) ClassLiteral(zone_, name, extends, constructor, properties,
-                                 start_position, end_position, id_gen_);
+                                 start_position, end_position);
     VISIT_AND_RETURN(ClassLiteral, lit)
   }
 
   NativeFunctionLiteral* NewNativeFunctionLiteral(const AstRawString* name,
                                                   v8::Extension* extension,
                                                   int pos) {
     NativeFunctionLiteral* lit =
-        new (zone_) NativeFunctionLiteral(zone_, name, extension, pos, id_gen_);
+        new (zone_) NativeFunctionLiteral(zone_, name, extension, pos);
     VISIT_AND_RETURN(NativeFunctionLiteral, lit)
   }
 
   ThisFunction* NewThisFunction(int pos) {
-    ThisFunction* fun = new (zone_) ThisFunction(zone_, pos, id_gen_);
+    ThisFunction* fun = new (zone_) ThisFunction(zone_, pos);
     VISIT_AND_RETURN(ThisFunction, fun)
   }
 
   SuperReference* NewSuperReference(VariableProxy* this_var, int pos) {
-    SuperReference* super =
-        new (zone_) SuperReference(zone_, this_var, pos, id_gen_);
+    SuperReference* super = new (zone_) SuperReference(zone_, this_var, pos);
     VISIT_AND_RETURN(SuperReference, super);
   }
 
 #undef VISIT_AND_RETURN
 
  private:
   Zone* zone_;
   Visitor visitor_;
   AstValueFactory* ast_value_factory_;
-  AstNode::IdGen* id_gen_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_