Avoid TLS load in AstNode constructor.

src/ast.h

 // 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
@@ skipping 116 matching lines @@
 #define DECLARE_TYPE_ENUM(type) k##type,
   enum Type {
     AST_NODE_LIST(DECLARE_TYPE_ENUM)
     kInvalid = -1
   };
 #undef DECLARE_TYPE_ENUM
 
   static const int kNoNumber = -1;
   static const int kFunctionEntryId = 2;  // Using 0 could disguise errors.
 
-  AstNode() {
-    Isolate* isolate = Isolate::Current();
+  // Override ZoneObjects's new to count allocated AST nodes.
+  void* operator new(size_t size, Zone* zone) {
+    Isolate* isolate = zone->isolate();
     isolate->set_ast_node_count(isolate->ast_node_count() + 1);
+    return zone->New(size);
   }
 
+  AstNode() {}
+
   virtual ~AstNode() { }
 
   virtual void Accept(AstVisitor* v) = 0;
   virtual Type node_type() const { return kInvalid; }
 
   // Type testing & conversion functions overridden by concrete subclasses.
 #define DECLARE_NODE_FUNCTIONS(type)                  \
   virtual type* As##type() { return NULL; }
   AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
 #undef DECLARE_NODE_FUNCTIONS
@@ skipping 14 matching lines @@
 
  protected:
   static unsigned GetNextId() { return ReserveIdRange(1); }
   static unsigned ReserveIdRange(int n) {
     Isolate* isolate = Isolate::Current();
     unsigned tmp = isolate->ast_node_id();
     isolate->set_ast_node_id(tmp + n);
     return tmp;
   }
 
+ private:
+  // Hidden to prevent accidental usage. It would have to load the
+  // current zone from the TLS.
+  void* operator new(size_t size);
+
   friend class CaseClause;  // Generates AST IDs.
 };
 
 
 class Statement: public AstNode {
  public:
   Statement() : statement_pos_(RelocInfo::kNoPosition) {}
 
   virtual Statement* AsStatement()  { return this; }
 
@@ skipping 1964 matching lines @@
 
  private:
   Isolate* isolate_;
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_